Monday, October 25, 2010

text neck

orlandosentinel.com/business/fl-hk-textneck-vasquez-1018-20101015,0,548346.column

OrlandoSentinel.com

The next tech-driven malady: 'Text Neck'

Plantation chiropractor spreads the word about posture and pain problems, creates app to help mobile device users

Daniel Vasquez on consumer issues

Sun Sentinel Columnist

6:58 AM EDT, October 18, 2010

Jennifer Chambers of Fort Lauderdale knew something was wrong when she noticed chronic pain shooting down her neck, through her arms to her fingertips, whenever she used her cell phone or laptop for prolonged periods.

Jenny Ottoson of Plantation sought medical help after suffering several years' of neck, back and shoulder pain that often flared up shortly after using her cell phone and laptop.

Chambers and Ottoson both have one thing in common, bouts of what Plantation chiropractor Dean L. Fishman calls "text neck."

It's the modern equivalent of tennis elbow, Fishman says, but instead of being brought on by sports activities it is exacerbated by improper posture while using smart phones, netbooks, iPads or any other mobile device.

"I had been talking about the problem with patients for years, using correct medical terms, but it was hard for people to understand what was going on until I gave it a name like 'Text Neck,'" says Fishman, who runs a sports rehabilitation practice.

Although the name has not caught on widely with the medical community, other experts say the relationship between bad posture and the use of mobile devices is a legitimate concern.

"I have not heard of text neck, but theoretically anytime you hold your neck in an awkward position for a prolonged time it will cause inflammation and irritation," said Jeffrey Cantor, a spine surgeon and founder of the South Florida Spine Clinic in Fort Lauderdale. "That could ultimately damage joints and cause arthritis."

Fortunately, fixing the ailment can be relatively simple, particularly when the condition is caught early. Experts recommend taking regular breaks when using mobile devices and resisting the temptation to flex the neck too much while using them. Fishman teaches his patients how to hold cell phones and mobile devices properly. He also advocates exercises that develop neck and shoulder muscles and chiropractic adjustments.

Fishman also developed a mobile phone app that helps alert users of a posture problem while texting or playing games on Android phones.

He came up with the name a year ago while trying to explain to a patient's mother why the girl was in pain. He noticed her teen-aged daughter in the corner texting friends, bending her neck forward as she typed. "I told the mom, 'See, that's what I am talking about, text neck.'"

Since then Fishman has been spreading the word to his patients that the condition can be painful and cause a lifetime of hurt if not corrected and treated. Today he says he treats patients daily with the problem.

Having spent years using mobile devices and experiencing similar pains, I have to say I had my "ah ha" moment after speaking with Fishman. Chambers, a patient care coordinator at a urgent care facility in Broward County who often uses her cell phone to text patients and doctors, had her "ah ha" moment after seeking help for chronic pain.

"I had pain for quite a long time after using cell phones and laptops," she said. "Now I know what a big thing posture is when using them."

Chambers said her condition has improved significantly since she began treatments with Fishman, which include chiropractic adjustments and a recommended exercise regimen at home. The chiropractic part takes about 10 minutes per session, she said. Initially, she went for adjustments about three times a week, but now goes in once a month.

Fishman charges his text-neck clients $45 per office visit, the same he charges other patients for similar treatments. Anyone considering such chiropractic treatments should check with their insurance carriers to find out whether they are covered.

Chambers said her exercises involve lying on her stomach and holding her head up for 10 seconds, releasing, and starting again, about 10 repetitions each time. Another exercise involves standing with the back of her feet against a wall and raising her hands "in angel motions."

"I have absolutely noticed a significant reduction in pain since I started these treatments," Chambers said.

Ottoson agrees. "I still have pain now and then, but not the flare-ups I used to get all the time," she said. Ottoson also uses the Text Neck app on her Android 2 phone.

The app works in the background, presenting a green or red light in the top left corner of the screen while users text. A green light means proper posture, red means the opposite. Users can adjust the app to beep or vibrate for posture alerts as well. The Text Neck App is available for $2.99 at the Android Market at android.com/market/. It is not available on iPhone, BlackBerries or other devices because of technical issues involving native operating systems, but Fishman hopes to overcome those in the future.

"Text Neck is basically a new name for a well-recognized disorder," said Jerome M. True, who also runs a chiropractic practice in Martin County, north of Palm Beach County.

In the past, True said, the disorder was brought on by poor posture while someone bent their neck to read a book in their lap or by a sports activity. "The problem with texting is," True said, "it is second nature for kids to lean forward to see the screen of the device in their lap, which causes fatigue and repetitive injury to the muscles in the neck and upper back."

"When the 12- to 20-year-olds of today get to be 40 years old, it will be most problematic and difficult to correct," he added.

Daniel Vasquez can be reached at CondoColumn@sunsentinel.com or 954-356-4219 begin_of_the_skype_highlighting              954-356-4219      end_of_the_skype_highlighting or 561-243-6686 begin_of_the_skype_highlighting              561-243-6686      end_of_the_skype_highlighting. His condo column runs Wednesdays in Your Money and at SunSentinel.com/condos. Check out Daniel's Condos & HOAs blog for news, information and tips related to life in community associations at SunSentinel.com/condoblog. You can also read his consumer column Mondays in Your Money and at sunsentinel.com/vasquez.

 

Monday, October 18, 2010

"Text Neck" causes pain problems and poor Posture

fox40.com/news/headlines/fl-hk-textneck-vasquez-1018-20101015,0,187341.column

KTXL

The next tech-driven malady: 'Text Neck'

Plantation chiropractor spreads the word about posture and pain problems, creates app to help mobile device users

Daniel Vasquez on consumer issues

Sun Sentinel Columnist

3:58 AM PDT, October 18, 2010

Jennifer Chambers of Fort Lauderdale knew something was wrong when she noticed chronic pain shooting down her neck, through her arms to her fingertips, whenever she used her cell phone or laptop for prolonged periods.

Jenny Ottoson of Plantation sought medical help after suffering several years' of neck, back and shoulder pain that often flared up shortly after using her cell phone and laptop.

Chambers and Ottoson both have one thing in common, bouts of what Plantation chiropractor Dean L. Fishman calls "text neck."

It's the modern equivalent of tennis elbow, Fishman says, but instead of being brought on by sports activities it is exacerbated by improper posture while using smart phones, netbooks, iPads or any other mobile device.

"I had been talking about the problem with patients for years, using correct medical terms, but it was hard for people to understand what was going on until I gave it a name like 'Text Neck,'" says Fishman, who runs a sports rehabilitation practice.

Although the name has not caught on widely with the medical community, other experts say the relationship between bad posture and the use of mobile devices is a legitimate concern.

"I have not heard of text neck, but theoretically anytime you hold your neck in an awkward position for a prolonged time it will cause inflammation and irritation," said Jeffrey Cantor, a spine surgeon and founder of the South Florida Spine Clinic in Fort Lauderdale. "That could ultimately damage joints and cause arthritis."

Fortunately, fixing the ailment can be relatively simple, particularly when the condition is caught early. Experts recommend taking regular breaks when using mobile devices and resisting the temptation to flex the neck too much while using them. Fishman teaches his patients how to hold cell phones and mobile devices properly. He also advocates exercises that develop neck and shoulder muscles and chiropractic adjustments.

Fishman also developed a mobile phone app that helps alert users of a posture problem while texting or playing games on Android phones.

He came up with the name a year ago while trying to explain to a patient's mother why the girl was in pain. He noticed her teen-aged daughter in the corner texting friends, bending her neck forward as she typed. "I told the mom, 'See, that's what I am talking about, text neck.'"

Since then Fishman has been spreading the word to his patients that the condition can be painful and cause a lifetime of hurt if not corrected and treated. Today he says he treats patients daily with the problem.

Having spent years using mobile devices and experiencing similar pains, I have to say I had my "ah ha" moment after speaking with Fishman. Chambers, a patient care coordinator at a urgent care facility in Broward County who often uses her cell phone to text patients and doctors, had her "ah ha" moment after seeking help for chronic pain.

"I had pain for quite a long time after using cell phones and laptops," she said. "Now I know what a big thing posture is when using them."

Chambers said her condition has improved significantly since she began treatments with Fishman, which include chiropractic adjustments and a recommended exercise regimen at home. The chiropractic part takes about 10 minutes per session, she said. Initially, she went for adjustments about three times a week, but now goes in once a month.

Fishman charges his text-neck clients $45 per office visit, the same he charges other patients for similar treatments. Anyone considering such chiropractic treatments should check with their insurance carriers to find out whether they are covered.

Chambers said her exercises involve lying on her stomach and holding her head up for 10 seconds, releasing, and starting again, about 10 repetitions each time. Another exercise involves standing with the back of her feet against a wall and raising her hands "in angel motions."

"I have absolutely noticed a significant reduction in pain since I started these treatments," Chambers said.

Ottoson agrees. "I still have pain now and then, but not the flare-ups I used to get all the time," she said. Ottoson also uses the Text Neck app on her Android 2 phone.

The app works in the background, presenting a green or red light in the top left corner of the screen while users text. A green light means proper posture, red means the opposite. Users can adjust the app to beep or vibrate for posture alerts as well. The Text Neck App is available for $2.99 at the Android Market at android.com/market/. It is not available on iPhone, BlackBerries or other devices because of technical issues involving native operating systems, but Fishman hopes to overcome those in the future.

"Text Neck is basically a new name for a well-recognized disorder," said Jerome M. True, who also runs a chiropractic practice in Martin County, north of Palm Beach County.

In the past, True said, the disorder was brought on by poor posture while someone bent their neck to read a book in their lap or by a sports activity. "The problem with texting is," True said, "it is second nature for kids to lean forward to see the screen of the device in their lap, which causes fatigue and repetitive injury to the muscles in the neck and upper back."

"When the 12- to 20-year-olds of today get to be 40 years old, it will be most problematic and difficult to correct," he added.

Daniel Vasquez can be reached at CondoColumn@sunsentinel.com or 954-356-4219 begin_of_the_skype_highlighting              954-356-4219      end_of_the_skype_highlighting or 561-243-6686 begin_of_the_skype_highlighting              561-243-6686      end_of_the_skype_highlighting. His condo column runs Wednesdays in Your Money and at SunSentinel.com/condos. Check out Daniel's Condos & HOAs blog for news, information and tips related to life in community associations at SunSentinel.com/condoblog. You can also read his consumer column Mondays in Your Money and at sunsentinel.com/vasquez.

 

Friday, October 15, 2010

Headaches and Neck Pain Linked to TEXTING

herald news


Neck pain and headaches linked to texting

 

From Submitted Reports

Last Modified: Sep 19, 2010 09:15PM

JOLIET -- More teens and young adults these days are suffering from headaches, tingling in the arm and neck pain resulting from too much leaning over hand-held devices and texting, according to Chiro One Wellness Centers.

"รข€Š 'Text neck' is a forward-head posture resulting from excessive strain on the spine from looking in a forward and downward position at any hand-held mobile device, mobile phone, video game unit, computer, mp3 player, or e-reader," said Dr. Andrea Blake, clinic director of Chiro One Wellness Center of Joliet. "This forward head posture can cause headaches, neck pain, shoulder and arm pain."

According to a recent study of 800 students ages of 12 to 17 conducted by the Pew Internet and American Life Project and the University of Michigan Department of Communication Studies, teenage girls send or receive an average of 80 text messages a day, and one third of teens who have cell phones text more than 100 messages daily. Teens use cell phone texts to communicate more than any other form of interaction, even face-to-face talking and instant messaging, according to the study.

Possible problems associated with "text neck" include: headaches, neck pain, shoulder pain, gastrointestinal issues, loss of lung capacity, pinched nerve and spine degeneration.

Chiro One Wellness Centers predicts that "text neck" is going to reach epidemic proportions because everyone is using some kind of hand-held device.

To avoid "text neck," Chiro One Wellness Centers suggests:

* Lift phone up and text at eye level rather than leaning over the phone, and look down with your eyes and gently tuck your chin in, not forward.

* Remember your posture. Sit upright, keeping your ears over your shoulders and hold the device below your heart.

* Keep the device 90 degrees perpendicular to your fingers as you press the buttons and use two hands to type.

* Support your forearms on a pillow during extended texting to reduce the strain on your neck and shoulder muscles.

* Remember to take a break to stretch and shake out the hands and stop when it hurts.

* Return only urgent e-mails. Respond to other e-mails from your computer.

* Do some stretches. Warm up hands by stretching the wrist backward for 2 to 3 seconds, then forward for 2 to 3 seconds. Spread your fingers as wide apart as you can and hold them for 2 to 3 seconds. Tuck your chin in and make a double chin, hold for 2 to 3 seconds. Fold your hands together and turn your palms away as you extend your arms forward.

* Monitor the time you spend on the phone or personal digital assistant (PDA) and be conscious of the risks involved with excessive use of PDAs or cell phones.

* Download new "Text Neck for Android" application at NeuroTilt.com to find out if you are at risk.

Chiro One Wellness Centers is offering free "text neck" posture checks in September. For more information, log on to ChiroOne.net/Events.

For location information, visit www.ChiroOne.net/locations or call 877-724-4761 begin_of_the_skype_highlighting              877-724-4761      end_of_the_skype_highlighting.


Copyright © 2010 — Sun-Times Media, LLC

 

Monday, October 4, 2010

Posture Perfect Torso .. Proven Exercises.

Back to basics: these six proven exercises will give you long, lean lines and a balanced, toned, posture-perfect torso - Shape's Best-Tested Moves

Shape, Oct, 2002 by Alexa Joy Sherman

We know that when it comes to seeking better body parts, few women say, "If only I could get a more attractive back!" But to achieve your ideal physique -- including flatter abs and shapelier shoulders -- working your back is crucial. That's because looking great and doing all of the things you love -- inside and outside the gym -- begin with a healthy back and a supple spine.http://dw.com.com/redir?tag=rbxira.2.a.10&destUrl=http://www.cnet.com/b.gif

But looking good isn't the only payoff; a strong back also will keep you healthier and free of pain, help you maintain proper alignment and good posture and build a terrifically toned torso, confirms Los Angeles-based rehabilitation specialist Craig Liebenson, D.C., editor of Rehabilitation of the Spine: A Practitioner's Manual (Lippincott, Williams & Wilkins, 1996). So which exercises will best strengthen your back while achieving your most beautiful lines to boot? To find out, we headed to the gym with Stuart Rugg, Ph.D., chair of the kinesiology department at Occidental College in Los Angeles. There, using an electromyograph (EMG), a machine that records muscle activity (the higher the EMO reading, the more active the muscles), we tested more than 40 upper-torso exercises for their effectiveness on the upper- and midback and spinal muscles. Six of the highest-ranking moves make up this exclusive workout, which also builds muscle in your shoulders to help make your waist and hips look smaller. The surprising g bonus: Your abdominal muscles work to stabilize you, so the result is a completely whittled middle.

YOUR BEST BACK PLAN OF ATTACK

How it works These are 6 of the best moves you can do for a stronger back and a healthy spine. The first 4 recruit the most muscles and force you to stabilize your position progressively with your abs; the final 2 are basic back exercises that require your abs to stabilize and increase muscle endurance.

Warm-up Begin with 5-10 minutes of low-intensity cardio. Try walking on a treadmill while swinging your arms or using any dual-action machine that requires the arms and legs to move at the same time.

Workout schedule Do these 6 moves in the order shown 2-3 times a week as part of a regular, total-body strength program, with 1 day off between strength sessions. (If you don't have time to do all 6 along with your regular strength program, do 3 moves, in any combination, selecting from the following: Do move 1 or 4; plus move 2 or 3; plus move 5 or 6.)

Sets/reps/weight guidelines If you've been exercising for less than 6 months, perform 2 sets of 8-12 reps for each exercise listed, resting 45-60 seconds between sets. Use as much weight as you can to complete all reps and sets with good form.

To progress For weighted moves, when 12 reps are no longer challenging, increase your weight by 2 1/2-5 pounds - or add a third set of 12 reps. For nonweighted exercises, increase reps by 2 at a time until you can do 15-20 per set. Note: You should not increase resistance or reps if doing so impedes proper form.

Cool-down Flexibility is vital to maintaining a healthy back and keeping a natural curve in the spine. (See "Finding Your 'Neutral Spine'" on page 160.) End each workout with 5-10 minutes of low-intensity cardio, followed by a total-back stretch: Stand with legs hip-width apart and grasp a support at arm's length with both hands. Bend knees into a quarter squat and round your spine, tucking pelvis under as you exhale. Straighten back to a neutral position and repeat 3-4 times.

the moves

1. Seated row Adjust the seat of a stack-row machine so you can sit with arms extended at shoulder height, knees bent and feet against foot plates and directly under knees. Holding the vertical handles, place chest gently against support pad without leaning and contract abdominals so spine is in a neutral position IA]. Squeeze shoulder blades together, then bend elbows, driving them back toward waist without changing torso position [B], Slowly straighten arms, being careful not to lock your elbows, and repeat. Weight: 30-80 pounds. Strengthens middle and upper back, rear deltoids and biceps

2. High seated row Sit at a low-cable-pulley machine with a long bar attached. Place feet against foot plates, knees slightly bent. Reach forward and grasp bar with an overhand grip, wider than shoulder-width apart, arms straight at chest height. Squeeze shoulder blades together and contract abdominals to maintain upright position without tucking tailbone under [A]. Without moving torso, bend elbows to bring bar toward chest, so forearms are parallel to floor, wrists straight and elbows out, even with shoulders [B] Slowly straighten arms, being careful not to lock elbows, without leaning forward, and repeat. Weight: 20-50 pounds. Strengthens upper back, front, middle and rear shoulders, and biceps

3. Smith reverse incline row Adjust the bar of a Smith machine so it's at the same height as the bottom of your rib cage. Extend arms to grasp bar with an underhand grip, hands slightly wider than shoulder-width apart. Contract abdominals so spine is in a neutral position, then walk feet forward under bar until the bar is over your chest and you are balancing on heels, arms extended, body in one straight line from head to heels [A]. Maintaining body position, bend elbows to pull yourself up toward bar; lead with chest, being careful not to strain your neck [B]. Slowly lower to starting. position and repeat. Weight: none. Strengthens upper and middle back, middle and rear shoulders, and biceps

FINDING YOUR NEUTRAL SPINE'

How to achieve it Stand with your feet hip-width apart, body weight balanced over the middle of your arches, legs straight. Without tightening your butt, contract your abs, drawing them inward to drop the tailbone down toward the floor. Gently squeeze your shoulder blades together to lift and open your chest; lengthen your neck so ears, shoulders, hips, knees and ankles are in one line, abs still tight.

What it is The neutral spine position occurs when your back and abdominal muscles contract synergistically, creating a balanced tension between the muscles in the front and back of your body, allowing you to maintain the natural curves of your spine - especially in the lower-back area. Thus, your body is completely aligned.

Additional tips Use your abdominals to bring ribs toward hips and hips toward ribs - gently, without collapsing your torso. Think of stacking your vertebrae, one on top of another, as if someone were pulling a string out of the top of your head. Imagine drawing the sides of your torso in toward the center, like a corset. Hold this position and continue to breathe normally.

Errors to avoid Don't squeeze your buttocks because this tends to pull your pelvis under, and don't shift your body weight too far forward, which can cause the back to arch excessively and the hips to roll forward.

4. Bent-over barbell row Standing with legs hip-width apart, hold a barbell with an overhand grip, hands separated slightly wider than shoulder-width. Contract abdominals to bring spine to a neutral position, squeeze shoulder blades together, then bend knees, bending forward at the hips until your back is parallel to the floor and bar hangs with arms straight in line with shoulders [A]. Maintaining this position, keep wrists straight and bend elbows up and in toward waist to bring bar toward lower rib cage [B]. Slowly straighten arms and repeat. Weight: 20- to 45-pound barbell. Strengthens upper and middle back, middle and rear shoulders, and biceps

5. Kneeling alternate arm and leg Kneel on all fours with knees hip-width apart, wrists under shoulders and arms straight but not locked. Contract abdominals to bring spine to a neutral position, so your body forms one straight line from head to hips [A]. Using abs to stabilize you, lift right arm up to shoulder height, fingers pointing straight ahead, and lift left leg up behind you to hip-height without losing balance [B]. Pause for 2 seconds, then lower and repeat with opposite arm and leg. Continue to alternate for all reps (1 lift on each side equals 1 rep). For the last rep on each side, hold position at least 30 seconds without moving. Weight: none. Strengthens and builds endurance of upper, middle and lower back, and front, middle and rear shoulders

6. Superwoman Lie face down on floor, arms extended flat above head, palms down, legs together. Contract abdominals to lift navel off floor, shifting tailbone down so spine is in a neutral position. Look down at the floor so neck and shoulders are relaxed [A]. Maintaining this position, inhale and lift both arms (from the shoulders) and both legs (from the hips) off the floor about 2-6 inches without creating tension in your lower back or neck (think of extending arms and legs rather than lifting) [B]. Pause for 2 seconds, then lower and repeat. Hold the final rep for about 20 seconds before lowering. Beginners can lift arms only, then legs only before attempting both together. Weight: none. Strengthens entire back, primarily front and middle shoulders

Bibliography for: "Back to basics: these six proven exercises will give you long, lean lines and a balanced, toned, posture-perfect torso - Shape's Best-Tested Moves"

Alexa Joy Sherman "Back to basics: these six proven exercises will give you long, lean lines and a balanced, toned, posture-perfect torso - Shape's Best-Tested Moves". Shape. FindArticles.com. 04 Oct, 2010. http://findarticles.com/p/articles/mi_m0846/is_2_22/ai_91233475/

COPYRIGHT 2002 Weider Publications

COPYRIGHT 2002 Gale Group

 

LA Garment Study: Better posture for Less Shoulder and neck Pain

http://www.medscape.com/viewarticle/558600

 

 

From Spine

A Randomized Controlled Trial Evaluating the Effects of New Task Chairs on Shoulder and Neck Pain Among Sewing Machine Operators: The Los Angeles Garment Study

David M. Rempel, MD, MPH; Pin-Chieh Wang, MS, PhD; Ira Janowitz, PT; Robert J. Harrison, MD, MPH; Fei Yu, PhD; Beate R. Ritz, MD, PhD

Posted: 06/25/2007; Spine. 2007;32(9):931-938. © 2007 Lippincott Williams & Wilkins

·         Print ThisPrint This

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·         Abstract and Introduction

·         Materials and Methods

·         Results

·         Discussion

·         Conclusion

·         References

·         Sidebar: Key Points

Abstract and Introduction

Abstract

Study Design: This is a 4-month randomized controlled trial to evaluate the effect of chair design on neck/shoulder pain among sewing machine operators.
Objective: Determine whether a chair with a curved seat pan leads to improved changes in monthly neck/shoulder pain scores compared with a control intervention.
Summary of Background Data: Sewing machine operators experience a high prevalence and severity of neck and shoulder pain in comparison to other working populations probably due to the sustained shoulder abduction and neck and upper back flexion required of the task. An adjustable height task chair that supports a forward sitting posture may reduce these posture-related risk factors and reduce neck/shoulder pain.
Materials and Methods: A total of 277 sewing machine operators with neck/shoulder pain were assigned to receive 1) miscellaneous items (control group), 2) a chair with a flat seat pan plus miscellaneous items, or 3) a chair with a curved seat pan plus miscellaneous items. Participants completed a monthly questionnaire assessing neck/shoulder pain severity.
Results: Based on estimates of pain score changes from a repeat-measures linear regression, participants who received the flat seat chair experienced a decline in pain of 0.14 (95% confidence interval, 0.07-0.22) points per month compared with those in the control group, while those who received the curved seat experienced a decline of 0.34 (95% confidence interval, 0.28-0.41) points per month compared with those in the control group. These estimates did not change after adjustment for potential covariates.
Conclusions: These findings demonstrate that an adjustable height task chair with a curved seat pan can reduce neck and shoulder pain severity among sewing machine operators.

Introduction

It has been reported that sewing machine operators experience more chronic neck or shoulder pain than other working populations.[1-5] In a cross-sectional study of 224 sewing machine operators, 67% reported neck or shoulder pain; based on physical examinations, 24% were diagnosed with tension neck syndrome and 20% with cervical syndrome.[6] In another study, physical examinations were performed on sewing operators and hospital workers randomly sampled from age-matched strata. Sewing machine operators received diagnoses of cervical syndrome, cervicobrachial fibromyalgia, and rotator cuff syndrome more often than hospital workers.[7]

In 2000, the garment industry employed 11 million workers worldwide with approximately 350,000 workers in the United States.[8] The Los Angeles basin is home to the largest garment production center in the United States. Most of the work is done by minimum wage, nonunion, immigrant women in shops that employ fewer than 20 people.[9] Sewing machine operators perform precision tasks at a relatively fast pace with work cycles of 30 to 60 seconds. This repetitive, stereotyped work is typically performed on nonadjustable workstations and chairs. The task demands and the lack of adjustability of the workstations may lead to sustained awkward postures, such as cervical and thoracic spine flexion and shoulder elevation and abduction (Figure 1), which may result in elevated rates of neck and shoulder pain.[6,7,10-13]

Click to zoom

(Enlarge Image)

Figure 1.

Typical posture of sewing operator with a conventional chair. Note flexed postures of thoracic and cervical spine and abduction of shoulder. Note also that the operator increased the height of the chair with paper cones.

[ CLOSE WINDOW ]

http://img.medscape.com/fullsize/migrated/558/600/sp558600.fig1.jpg

Figure 1.

Typical posture of sewing operator with a conventional chair. Note flexed postures of thoracic and cervical spine and abduction of shoulder. Note also that the operator increased the height of the chair with paper cones.

A pilot study by our group, carried out at sewing shops in Oakland, CA, evaluated a variety of workstation interventions with the goal of reducing neck, thoracic and lumbar spine flexion, shoulder elevation, and shoulder abduction during garment work. Examples of the workstation changes we studied were: sloping of the work surface toward the operator; adding side tables to support the material and reduce reach; providing reading glasses; adding task lamps; providing a foam wedge for the seat; providing a new chair; and adding a foot rest. Ultimately, the intervention that appeared most likely to reduce risk factors for neck and shoulder pain was a new task chair with a curved, 2-part seat pan (Figure 2) based on principles proposed for industrial work.[14-16] Theoretically, the 2-part seat pan supports the forward leaning posture by allowing a more open thigh-torso angle, thereby retaining the lumbar curvature and a less kyphotic thoracic spine. The pelvis is supported on the more horizontal rear part of the seat to prevent forward sliding associated with a forward sloping seat pan. The seat was also adjustable in height and slope to accommodate different task demands and employees of different stature.

Click to zoom

(Enlarge Image)

Figure 2.

Design concept for a task chair with a 2-part, curved seat pan, which supports forward leaning by allowing a more open thigh-torso angle and preserving lumbar lordosis.

[ CLOSE WINDOW ]

http://img.medscape.com/fullsize/migrated/558/600/sp558600.fig2.gif

Figure 2.

Design concept for a task chair with a 2-part, curved seat pan, which supports forward leaning by allowing a more open thigh-torso angle and preserving lumbar lordosis.

The purpose of the intervention study we are reporting here was to compare the impact of this new task chair, a conventional task chair, and a placebo intervention on neck and shoulder pain in industrial sewing operators. The primary outcomes evaluated were monthly neck and shoulder pain severity. The null hypothesis was that the change in neck and shoulder pain scores would be the same in all 3 intervention groups over a 4-month period.

 

 

Too Much Sitting? Sedentary behavior

http://www.medscape.com/viewarticle/725341_3

 

Authors and Disclosures

Neville Owen1,2, Geneviรจve N. Healy1,2, Charles E. Matthews3, and David W. Dunstan2

1The University of Queensland, School of Population Health, Cancer Prevention Research Centre, Brisbane, Australia; 2Baker IDI Heart and Diabetes Institute, Melbourne, Australia; and 3Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD

Address for correspondence
Neville Owen, Ph.D., The University of Queensland, Cancer Prevention Research Centre, School of Population Health, Level 3, Public Health Bldg., Herston Rd., Herston QLD 4006, Australia (E-mail: n.owen@sph.uq.edu.au).

From Exercise and Sport Sciences Reviews

Too Much Sitting: The Population Health Science of Sedentary Behavior

Neville Owen; Geneviรจve N. Healy; Charles E. Matthews; David W. Dunstan

Abstract and Introduction

Abstract

Even when adults meet physical activity guidelines, sitting for prolonged periods can compromise metabolic health. Television (TV) time and objective measurement studies show deleterious associations, and breaking up sedentary time is beneficial. Sitting time, TV time, and time sitting in automobiles increase premature mortality risk. Further evidence from prospective studies, intervention trials, and population-based behavioral studies is required.

Introduction

The physical, economic, and social environments in which modern humans sit or move within the contexts of their daily lives have been changing rapidly, and particularly so since the middle of the last century. These changes — in transportation, communications, workplace, and domestic entertainment technologies — have been associated with significantly reduced demands for physical activity. However, these reductions in the environmental demands for being physically active are associated with another class of health-related behaviors.

Sedentary behaviors (typically in the contexts of television (TV) viewing, computer and game console use, workplace sitting, and time spent in automobiles) have emerged as a new focus for research on physical activity and health.[18,27,31–33] Put simply, the perspective that we propose is that too much sitting is distinct from too little exercise. Research findings on sedentary behavior and health have proliferated in the 10 yr after publication of our first Exercise and Sport Sciences Reviews article on this topic.[32] As we will demonstrate, initial findings on the metabolic correlates of prolonged TV viewing time have since been confirmed by recent objective measurement studies, which also show that breaking up sedentary time can be beneficial. Furthermore, we describe recent studies from Canada, Australia, and the United States, which show prospective relationships of sedentary behaviors with premature mortality. Importantly, adults can meet public health guidelines on physical activity, but if they sit for prolonged periods, their metabolic health is compromised. This is a new and challenging area for exercise science, behavioral science, and population health research. However, many scientific questions remain to be answered before it can be concluded with a high degree of certainty that these adverse health consequences are uniquely caused by too much sitting, or if what has been observed so far can be accounted for by too little light, moderate, and/or vigorous activity.

The updated recommendation for adults on Physical Activity and Public Health from the American College of Sports Medicine and the American Heart Association (ACSM/AHA) clearly states that "the recommended amount of aerobic activity (whether of moderate or vigorous intensity) is in addition to routine activities of daily living, which are of light intensity, such as self-care, casual walking, or grocery shopping, or less than 10 min of duration such as walking to the parking lot or taking out the trash" (,[20] p. 1426). Logically, doing such daily activities differently could involve reductions in sitting time, but sitting per se is not addressed specifically in the recommendations. In this context, the key question to be asked about the strength of the evidence on sedentary behavior and health that we present in this article is: Would one expect to see a statement on reducing sitting time included in future physical activity recommendations?

Sedentary Behavior

Sedentary behaviors (from the Latin sedere, "to sit") include sitting during commuting, in the workplace, the domestic environment, and during leisure time. Sedentary behaviors such as TV viewing, computer use, or sitting in an automobile typically are in the energy expenditure range of 1.0–1.5 METs (multiples of the basal metabolic rate).[1] Thus, sedentary behaviors are those that involve sitting and low levels of energy expenditure. In contrast, moderate- to vigorous-intensity physical activities such as bicycling, swimming, walking, or running may be done in a variety of body positions, but require an energy expenditure of 3–8 METs.[1] In this perspective, light-intensity activity behaviors are those done while standing that require an expenditure of no more than 2.9 METs.

Addressing research on the health consequences of sedentary behavior requires some initial clarification of terminology. We refer to sedentary behaviors (different activities for different purposes in different contexts; see previous description). We also refer to sitting time, a generic descriptor covering what these sedentary behaviors primarily involve. As we demonstrate later, adults spend most of their waking hours either sitting or in light-intensity activity (predominantly standing with some gentle ambulation).

Time in sedentary behaviors is significant, if only because it displaces time spent in higher-intensity physical activity — contributing to a reduction in overall physical activity energy expenditure. For example, displacement of 2 h·d−1 of light-intensity activity (2.5 METs) by sedentary behaviors (1.5 METs) would be predicted to reduce physical activity energy expenditure by about 2 MET-h·d−1 or approximately the level of expenditure associated with walking for 30 min·d−1 (0.5 h * 3.5 METs = 1.75 MET-h).

Research on physical activity and health has concentrated largely on quantifying the amount of time spent in activities involving levels of energy expenditure of 3 METs or more, characterizing those with no participation at this level as "sedentary".[33] However, this definition neglects the substantial contribution that light-intensity activities make to overall daily energy expenditure[8] and also the potential health benefits of participating in these light-intensity activities, rather than sitting. Furthermore, although individuals can be both sedentary and physically inactive, there is also the potential for high sedentary time and physical activity to coexist (the Active Couch Potato phenomenon, which we will explain later). An example would be an office worker who jogs or bikes to and from work, but who then sits all day at a desk and spends several hours watching TV in the evening.

Common behaviors in which humans now spend so much time — TV viewing, computer use and electronic games, sitting in automobiles — involve prolonged periods of low-level metabolic energy expenditure. It is our contention that sedentary behavior is not simply the absence of moderate- to vigorous-intensity physical activities, but rather, is a unique set of behaviors with unique environmental determinants and a range of potentially unique health consequences.[43] Our population health research perspective is on the distinct role of sedentary behavior, as it may influence obesity and other metabolic precursors of major chronic diseases (type 2 diabetes, cardiovascular disease, and breast and colon cancers).

Sedentary Behavior and Health: A Unique Underlying Biology?

Physiologically, distinct effects are observed between prolonged sedentary time and too little physical activity.[17] There are broad consistencies between the patterns of findings from epidemiological studies on the cardiometabolic correlates of prolonged sitting that we will describe, and recent evidence on biological mechanisms ("inactivity physiology") identified in animal models. It seems likely that there is a unique physiology of sedentary time, within which biological processes that are distinct from traditionally understood exercise physiology are operating. The groundbreaking work of Hamilton and colleagues[3,16] provides a compelling body of evidence that the chronic unbroken periods of muscular unloading associated with prolonged sedentary time may have deleterious biological consequences. Physiologically, it has been suggested that the loss of local contractile stimulation induced through sitting leads to both the suppression of skeletal muscle lipoprotein lipase (LPL) activity (which is necessary for triglyceride uptake and high-density lipoprotein (HDL) cholesterol production) and reduced glucose uptake.[3,16] A detailed account of findings and implications from the studies of Hamilton et al. [17,18] has been provided in recent reviews.

Findings by Hamilton et al. [17,18] suggest that standing, which involves isometric contraction of the antigravity (postural) muscles and only low levels of energy expenditure, elicits electromyographic and skeletal muscle LPL changes. However, in the past, this form of standing would be construed as a "sedentary behavior" because of the limited amount of bodily movement and energy expenditure entailed. This highlights the need for an evolution of the definitions used for sedentary behavior research. Within this perspective, standing would not be a sedentary activity, and our approach (subject to revision as further findings accumulate) is to equate "sedentary" with "sitting."

The Metabolic Health Consequences of Too Much Sitting

TV Viewing Time: The AusDiab Studies

The Australian Diabetes, Obesity and Lifestyle Study (AusDiab) was conducted initially in 1999/2000 on a common leisure time sedentary behavior — TV viewing time (TV time) — with biomarkers of cardiometabolic risk. AusDiab recruited a large population-based sample of some 11,000 adults from all Australian states and the Northern Territory. Some of our first AusDiab findings were that among adults without known diabetes, self-reported TV time was positively associated with undiagnosed abnormal glucose metabolism[12] and the metabolic syndrome.[11] The strongest relationships were observed in the highest TV time category (4 h·d−1 or more). When TV time was considered as a continuous measure,[10] a detrimental dose-response association was observed in women between TV time and 2-h plasma glucose and fasting insulin. Importantly, all of these associations persisted after adjustment for sustained moderate- to vigorous-intensity leisure time physical activity and waist circumference. Some of these cross-sectional relationships have been replicated recently in prospective analyses: increases in TV viewing during 5 yr predicted significant adverse changes in waist circumference for men and women and in diastolic blood pressure and a clustered cardiometabolic risk score for women. These associations were independent of baseline TV time, baseline physical activity and physical activity change, and other potential confounders.[48]

Being Sedentary and Meeting Physical Activity Guidelines: The Active Couch Potato

We further examined relationships of TV time with continuous metabolic risk in men and women who reported at least 150 min·wk−1 of moderate- to vigorous-intensity physical activity — the generally accepted public health guidelines for health-enhancing physical activity.[20] Among these healthy physically active adults, significant detrimental dose-response associations of TV time were observed with waist circumference, systolic blood pressure, and 2-h plasma glucose in both men and women, as well as fasting plasma glucose, triglycerides, and HDL cholesterol in women only.[23] This observation — the Active Couch Potato phenomenon — is important. The particular metabolic consequences of time spent watching TV are adverse, even among those considered to be sufficiently physically active to reduce their chronic disease risk. This finding reinforces the potential importance of the deleterious health consequences of prolonged sitting time, which may be independent of the protective effect of regular moderate-intensity physical activity.

TV Viewing Time: Associations With Biomarkers for Men and for Women

One of the striking findings in the AusDiab TV time studies was that the associations with cardiometabolic biomarkers were stronger for women than for men.[10–12,23] We subsequently examined the associations of both TV time and self-reported overall sitting time with these biomarkers in the 2004/2005 AusDiab sample.[42] The TV time relationships for women were replicated, but for self-reported overall sitting time (which is inclusive of the TV time component), the associations were similar for men and women. So, the question remains as to whether there is a particular relationship of TV time with metabolic health for women. There are some testable hypotheses that can be put forward in this context: Are there dietary or TV time-related snacking differences between men and women? Are women (who have a lower average skeletal muscle mass and a higher average fat mass than men) metabolically more susceptible to the adverse influences of prolonged sitting after a typically large evening meal?

Although some of our most striking initial findings on the adverse health consequences of sedentary behavior have been for TV time, there should be caution in treating this common leisure time sedentary behavior as a marker for overall sedentary time. We have modest evidence[39] that for women, TV time is positively correlated with other leisure time sedentary behaviors and with being less likely to meet physical activity and health guidelines. However, these findings need to be replicated in other populations and with other measures. Furthermore, TV viewing is associated with other health-related behaviors,[51] and those in the highest TV time categories are more likely to eat in front of the TV set.[26] It is thus plausible that TV time will influence energy balance in two main ways. Most people sit to watch TV, and it has a lower energy cost than the alternative activities that it replaces. In addition, high levels of TV time are likely to increase energy intake because of prompts from frequent commercials about food and beverages, and unlike for many other activities, the hands are free to eat during TV time.[51] It is thus a reasonable hypothesis that this latter factor may partially explain why higher levels of TV time are associated with higher waist circumferences and with adverse blood glucose and lipid profiles.

We must emphasize that TV time is one of a number of sedentary behaviors that characterize how adults go about their daily lives, and there is potential measurement error associated with using the self-report measures that are common to most TV time studies. However, based on our recent systematic review,[6] we have some confidence that the TV time measures that we have used are reasonably reliable and valid.

Objective Assessment of Sedentary Time: New Findings

Advances in the Objective Measurement of Sedentary Behavior

These Australian studies previously summarized have all relied on self-reported TV time or overall sitting time. However, advances in measurement technology now provide significantly enhanced scientific traction, which is helping to deal with the methodological limitation of measurement error related to the use of self-report items. Before summarizing findings from our objective measurement studies with AusDiab study participants, it is helpful to consider the new perspectives that emerge when accelerometer data on sedentary time and physical activity are examined. Accelerometers (as distinct from pedometers that count and display the number of steps taken) are small electronic devices worn on the hip that provide an objective record of the volume, intensity, and frequency of activity between and within days, which may be downloaded to computer databases and used to derive scientifically meaningful activity variables. Accelerometers have been used as part of the National Health and Nutrition Examination Survey (NHANES), gathering data from large population-based samples of adult residents of the United States. Findings reported to date suggest that compared with what has been assumed to be the case from self-report surveys, levels of participation in moderate- to vigorous-intensity physical activities are extremely low,[44] and that some 60% or more of these adults' waking hours are spent sedentary.[29]

Sedentary Behavior during Adults' Waking Hours

To illustrate the overall patterns of activity in adults' daily lives, Figure 1 shows a cluster heat map.[50] This is a graphic representation from Genevieve Healy, showing accelerometer data for one individual during 1 wk, in the manner originally presented by Foulis et al.[15] The values taken by the accelerometer counts within each minute are represented as colors in the two-dimensional map. The dark blue shading shows accelerometer counts that are less than the currently used, but still debated, cutoff of 100 counts per min for sedentary time, and which are taken to be indicative predominantly of sitting (a caveat, however, is that some of the minutes shown as sedentary will include standing quite still). The pale blue through yellow colorings indicate light-intensity to moderate-intensity physical activities. The yellow through red colorings indicate moderate- to vigorous-intensity physical activity. From an energy expenditure perspective, the dark blue translates to very low levels of energy expenditure, with the red reflecting high energy expenditure levels. What is striking in Figure 1 is the extent to which this person spends his or her time either in light-intensity activities (pale blue to white) and being sedentary (dark blue). Although we would not contend that this is a totally precise and unambiguous representation of sitting time and light-, moderate-, and vigorous-intensity activities, it nevertheless is an informative perspective.

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Figure 1.  Being physically active, but also highly sedentary: 1 wk of accelerometer count data showing, on average, 31 min·d−1 moderate- to vigorous-intensity activity time (>1951 counts per minute) and 71% of waking hours sedentary (<100 counts per minute).

Figure 1 illustrates one of our key messages about the role of sedentary time in the physical activity and health equation: it is possible to achieve a level of activity consistent with the public health guidelines for health-related physical activity (30 min of moderate-intensity physical activity on most days of the week) but to spend most of waking hours involved in sedentary behaviors. In this case, we see that the accumulated moderate- to vigorous-intensity physical activity time is 31 min; however, this person spends 71% of his or her waking hours in sedentary time. Thus, it is possible for individuals to be physically active, yet highly sedentary — the Active Couch Potato phenomenon identified in the AusDiab TV time studies.[24]

The main scientific caveat for this perspective is that these data show "activity," which we infer is reflective of "behavior." However, there are scientific devils in the details of these objective movement data. Debate remains about what are the most appropriate activity count cut points to identify sedentary and light-intensity activity time; also, different cut points may be appropriate for adults of different ages, race/ethnicity, and adiposity status.

Objectively Assessed Sedentary Time: Key Studies

As well as demonstrating remarkably low levels of physical activity and high levels of sedentary time within contemporary human environments,[29,44] objective measures also have demonstrated the adverse impact of prolonged sedentary time on cardiometabolic biomarkers of risk. At least three studies in Europe and Australia have examined the associations of objectively measured sedentary time with continuous cardiometabolic biomarkers: the ProActive trial conducted in the United Kingdom (UK), the European RISC study, and the AusDiab study.[2,13,14,23,25] For those in the UK ProActive trial (258 participants aged 30–50 yr with a family history of type 2 diabetes), sedentary time was detrimentally associated with insulin in the cross-sectional analysis[14] but was of borderline statistical significance (P = 0.07) in the 1-yr prospective analysis.[13] Detrimental cross-sectional associations of sedentary time with insulin also were observed in participants of the European RISC study (801 healthy participants aged 30–60 yr), although the associations were attenuated after adjustment for total activity.[2] In the AusDiab accelerometer study sample (169 participants aged 30–87 yr, general population), we observed detrimental associations of sedentary time with waist circumference, triglyceride levels, and 2-h plasma glucose.[22,24] It is important to point out that the participants in all of these studies were primarily white adults of European descent.[2,13,14,22,24] A key next step for this research is to examine whether the associations are consistent across different racial/ethnic groups, which is becoming feasible with the public availability of large multiethnic population-based data sets, particularly NHANES.[29,44]

Objectively Assessed Sedentary Behavior: AusDiab Findings

We used accelerometers to assess sedentary time in a subsample of the AusDiab study participants. Sedentary time was defined as accelerometer counts less than 100 per minute (previously described) and was associated with a larger waist circumference and more adverse 2-h plasma glucose and triglyceride profiles, as well as a clustered metabolic risk score.[22,24] The associations of sedentary time with these biomarkers (with the exception of triglyceride levels) remained significant after adjustment for time spent in moderate- to vigorous-intensity physical activities.[22,24]

As logically would be expected, sedentary time and light-intensity activity time were highly negatively correlated (r = −0.96); more time spent in light-intensity activity is associated with less time spent sedentary. This suggests that it may be a feasible approach to promote light-intensity activities as a way of ameliorating the deleterious health consequences of sedentary time. Our evidence suggests that having a positive light-intensity activity/sedentary time balance (i.e., spending more time in light-intensity activity than sedentary time) is desirable because light-intensity activity has an inverse linear relationship with a number of cardiometabolic biomarkers.[22,24]

Breaks in Sedentary Time: AusDiab Findings

One of the intriguing findings from our accelerometer measurement studies is that breaks in sedentary time (as distinct from the overall volume of time spent being sedentary) were shown to have beneficial associations with metabolic biomarkers.[21] Sedentary time was considered to be interrupted if accelerometer counts rose up to or more than 100 counts per min.[21] This can include behaviors that result in a transition from sitting to a standing position or from standing still to beginning to walk. Figure 2 is based on data from two of our AusDiab accelerometer study participants, showing a simple contrast between adults who have the same total volume of sedentary time, but who break up that time in contrasting patterns. The person whose data are shown in the right-hand panel of Figure 2 (the "Breaker") interrupts his or her sedentary time far more frequently than the person whose data are shown on the left panel (the "Prolonger").

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Figure 2.  Breaks in sedentary time: same amount of sedentary time, but different ways of accumulation. CPM, counts per minute. (Reprinted from Dunstan DW, Healy GM, Sugiyama T, Owen N. Too much sitting and metabolic risk — has modern technology caught up with us? US Endocrinol. 2009; 5(1):29–33. Copyright © 2009 Touch Briefings. Used with permission.)

Independent of total sedentary time, moderate- to vigorous-intensity activity time, and mean intensity of activity, we found that having a higher number of breaks in sedentary time was beneficially associated with waist circumference, body mass index, triglycerides, and 2-h plasma glucose.[21] Figure 3 shows objectively measured waist circumference across quartiles of breaks in sedentary time. Those in the bottom quarter of the "breaks" distribution had, on average, a 6-cm larger waist circumference than did those in the top quarter of that distribution.[21]

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Figure 3.  Associations of breaks in sedentary time with waist circumference (based on data from Healy et al.[21]).

These findings on breaks in sedentary time provide intriguing preliminary evidence on the likely metabolic health benefits of regular interruptions to sitting time, which we would argue are additional to the benefits that ought to accrue from reducing overall sedentary time. Interestingly, in a recent study,[5] patterns of sedentary time accumulation (but not total sedentary time) were shown to differ among four groups of adults with various activity patterns (healthy group with active occupation, healthy group with sedentary occupation, group with chronic back pain, group with chronic fatigue syndrome). As we will go on to propose, although we believe that these are strongly indicative findings, there is the need to determine whether these associations can be confirmed in experimental manipulations of sitting time in the laboratory. Intervention studies where sedentary time is reduced or broken up in naturalistic settings such as the domestic environment or the workplace would also be needed.

Sedentary Behavior and Mortality

The significance of the evidence on the adverse cardiometabolic health consequences of prolonged sitting time is underscored by findings from a mortality follow-up of participants in the Canada Fitness Surveys. Canadians who reported spending most of their day sitting had significantly poorer long-term mortality outcomes than did those who reported that they spent less time sitting. These relationships with mortality were consistent across all levels of a self-report measure of overall sitting time. Participants estimated the broad fractions of their waking hours that were spent sitting. Importantly, the sitting time-mortality relationships were apparent even among those who were physically active and the relationships were stronger among those who were overweight or obese.[25] In a follow-up of AusDiab study participants during 6.5 yr, high levels of TV time were significantly associated with increased all-cause and cardiovascular disease mortality rates.[9] Each 1-h increment in TV time was found to be associated with an 11% and an 18% increased risk of all-cause and cardiovascular disease mortality rates, respectively. Furthermore, relative to those watching less TV (<2 h·d−1), there was a 46% increased risk of all-cause mortality and an 80% increased risk of cardiovascular disease mortality in those watching TV 4 h·d−1 or more. These increased risks were independent of traditional risk factors such as smoking, blood pressure, cholesterol level, and diet, as well as leisure time physical activity and waist circumference. A recent study from the United States[47] examined sedentary behaviors in relation to cardiovascular mortality outcomes based on 21 yr of follow-up of 7744 men. Those who reported spending more than 10 h·wk−1 sitting in automobiles (compared with <4 h·wk−1) and more than 23 h of combined television time and automobile time (compared with <11 h·wk−1) had an 82% and 64% greater risk of dying from cardiovascular disease, respectively. TV time alone was not a significant predictor.[47]

Research Directions

Looking Back through a Sedentary Behavior Lens

Emerging findings on sedentary behavior suggest a different perspective through which findings of earlier physical activity and health research studies may be reexamined (we thank William L. Haskell, Ph.D., FACSM for stimulating these observations). For example, physical activity epidemiology studies that have assessed physical activity comprehensively often have included measures of sitting time, which has been used mainly to derive overall daily energy expenditure estimates. We would predict (perhaps boldly) that if such studies were to be revisited, with further analyses being conducted using sitting time as a distinct exposure variable, that strong evidence would be found for deleterious effects on subsequent health outcomes, independent of those related to physical inactivity.

Other potentially fruitful areas in which the relevance of existing evidence could be reexamined are the NASA zero-gravity studies. Comparing findings of those studies (which relate to the metabolic consequences of extreme muscular unloading) with those of the recent findings from inactivity physiology[16,17] may yield further insights relating to the underlying biology of prolonged sedentary time.

Research on physical activity and health had its roots in early occupational epidemiological studies that assessed workers in jobs that primarily involve sitting as the comparison groups against which the protective benefits of physically active work were highlighted.[4,17,18] In the perspective of the new evidence that we have highlighted, conducting further occupational epidemiological studies using new objective measurement capabilities and examining a range of cardiometabolic and inflammatory biomarkers as intermediate outcomes could yield valuable insights.

Sedentary Behavior Research Strategy

Our population health research program on sedentary behavior is guided by the behavioral epidemiology framework.[34,36] Figure 4 shows six research phases. As we previously demonstrated, evidence within the first phase (examining the relationships of sedentary behavior to cardiometabolic biomarkers and health outcomes) has strengthened rapidly during the past 10 yr.

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Figure 4.  Behavioral epidemiology framework: phases of evidence for a population health science of sedentary behavior.

Prolonged periods of sitting in people's lives need to be measured precisely (phase 2). Their contextual determinants — that is, behavior settings [32,35] — need to be identified in domestic, workplace, transportation, and recreation contexts (phase 3). We have argued previously for a research focus on the distinct environmental determinants of sedentary behaviors, in contexts where they can be amenable to intervention.[31,32,37,41] The feasibility and efficacy of such interventions need to be tested rigorously (phase 4). Importantly, public health policy responses need to be informed by evidence from all of these phases. Compared with the challenges for physical activity and public health,[19] sedentary behavior may be less of a "moving target" in this context and may be shown to be a tractable public health objective.[4]

The Population Health Science of Sedentary Behavior: Research Opportunities

Different sedentary behaviors and their interactions with physical activity need to be examined in a range of contexts. For example, we have demonstrated that leisure time Internet and computer use is related to overweight and obesity in Australian adults,[45] and that habitual active transport reduces the impact of TV time on body mass index.[40] Having identified these relationships, our program is now broadening the evidence base through research with other populations. New studies include work with the large population-based data set from the NHANES from the United States, examining potential racial and ethnic differences in the relationships of total sedentary time and breaks in sedentary time with cardiometabolic biomarkers. We have demonstrated significant associations of TV time with excess body weight among high school students in regional mainland China.[52] In the context of the rapid economic development and increasing urbanization among the populations of many developing countries, documenting the health consequences of reductions in physical activity and increases in sedentary time will be crucial for informing preventive health measures.[38]

Studies with high-risk groups also are required. For example, we examined accelerometer-derived physical activity, sedentary time, and obesity in breast cancer survivors, showing physical activity to be protective, but there was no deleterious relationship for sedentary time.[28] Significant prospective relationships of TV time with weight gain during 3 yr were identified in a large population-based cohort of Australian colorectal cancer survivors.[49] More such etiologic research is needed to examine potential relationships between too much sitting and the development of other diseases that have been linked to metabolic risk factors.

For the second phase of the behavioral epidemiology framework (measurement; Fig. 4), there is the need to identify the reliability and validity of self-report instruments.[6] Population-based descriptive epidemiological studies using high-quality measures are needed. For example, we have shown that Australian adults with lower levels of educational attainment and those living in rural areas are more likely to be in the highest TV time categories.[7] We also have demonstrated that for Australian women, being in the higher categories of TV time can be associated with a broader pattern of leisure time sedentary behavior and with being less likely to meet physical activity recommendations.[39] Using American Cancer Society data from a large population-based study, we have identified clusters of adults in the 4 h or more category of TV time who are less educated, obese, and snacking while watching TV.[26]

Studies have begun to identify the environmental correlates of sedentary behavior, and initial findings seem puzzling. Among urban Australians, lower levels of objectively assessed neighborhood walkability (poorly connected streets, low levels of residential density, and limited access to destinations) were found to be associated with higher TV time in women.[41] However, a recent study in the city of Ghent, Belgium, showed higher levels of walkability to be associated with higher amounts of accelerometer-assessed sedentary time.[46] These apparently contradictory outcomes require further research. Such findings have potential implications for the emerging area of research on built environment/obesity relationships, within which sedentary behavior is likely to have a significant role.[30]

Research on sedentary behaviors also needs to be extended beyond the promising initial studies on TV time to understand the potential health consequences of other common sedentary behaviors. Evidence on the metabolic correlates of prolonged sitting in motor vehicles would be particularly informative in the light of recent evidence on relationships with premature mortality.[47] The social and environmental attributes associated with high levels of time spent sitting in automobiles also need to be identified.

The highest priority for the sedentary behavior research agenda is to gather new evidence from prospective studies, human experimental work, and intervention trials. There is the particular need to build on the promising findings on relationships of sedentary time — overall sitting time, TV time, and time sitting in automobiles — with premature mortality.[9,25,47] Controlled experimental studies with humans also should be particularly informative. For example, we are currently conducting a laboratory study experimentally manipulating different "sedentary break" conditions and examining associated changes in cardiometabolic biomarkers (focusing on levels of triglycerides, glucose, and insulin).

Field studies also are needed on the feasibility and acceptability of reducing and breaking up occupational, transit, and domestic sedentary time. For example, in a weight control intervention trial for adults with type 2 diabetes, we are testing the impact of a sedentary behavior reduction intervention module and examining behavioral and biomarker changes associated with reducing and breaking up sedentary time. There are multiple research opportunities that can be explored through integrating sedentary behavior change intervention into physical activity trials. When accelerometer data are gathered from such studies, sedentary time measures can be derived,[21,22,24] and unique hypotheses may readily be tested. It is imperative that the field now moves to obtain such evidence through intervention trials, which will take the science beyond the inherent logical limitations of cross-sectional evidence.

Eleven Research Questions for a Science of Sedentary Behavior

1.     Can further prospective studies examining incident disease outcomes confirm the initial sedentary behavior/mortality findings?

2.     Can sedentary behavior/disease relationships be identified through reanalyses of established prospective epidemiological data sets by treating sitting time as a distinct exposure variable?

3.     What are the most valid and reliable self-report and objective measures of sitting time for epidemiological, genetic, behavioral, and population health studies?

4.     Are the TV time-biomarker relationships for women pointing to important biological and/or behavioral sex differences?

5.     What amounts and intensities of activity might be protective in the context of prolonged sitting time?

6.     What genetic variations might underlie predispositions to sit and greater susceptibility to the adverse metabolic correlates?

7.     What is the feasibility of reducing and/or breaking up prolonged sitting time for different groups (older, younger) in different settings (workplace, domestic, transit)?

8.     If intervention trials show significant changes in sitting time, are there improvements in the relevant biomarkers?

9.     What are the environmental determinants of prolonged sitting time in different contexts (neighborhood, workplace, at home)?

10.  What can be learned from the sitting time and sedentary time indices in built-environment/physical activity studies?

11.  Can evidence on behavioral, adiposity, and other biomarker changes be gathered from "natural experiments" (e.g., the introduction of height-adjustable workstations or new community transportation infrastructure)?

Practical and Policy Implications of a Science of Sedentary Behavior

Practical and policy approaches to addressing too much sitting as a population health issue will involve innovations on multiple levels. For example, public information campaigns may emphasize reducing sitting time as well as increasing physical activity. There may be more widespread use of innovative technologies that can provide more opportunities to reduce sitting time (e.g., height-adjustable desks) or new regulations in workplaces to reduce or break up extended periods of job-related sitting. Active transport modes can be promoted not only as opportunities for walking, but also as alternatives to the prolonged periods that many people spend sitting in automobiles. Providing nonsitting alternatives at community entertainment venues or events also may be considered. If evidence on the deleterious health impact of too much sitting continues to accumulate as we predict, and if such innovations are implemented, there will be the need for systematic evaluations, particularly of approaches that have the potential for broader dissemination.

Anecdotally, the recent experience in Australia has been that initiatives in the final phase of the behavioral epidemiology framework ("using relevant evidence to inform public health guidelines and policy") have already begun. This is happening largely on the basis of the first-phase evidence presented in Figure 4 ("identifying relationships of sedentary behavior with health outcomes"). For example, the Australian National Preventative Health Task Force Report includes explicit recommendations to address prolonged sitting in the workplace in the context of reducing the burden of overweight and obesity, type 2 diabetes, and cardiovascular disease. The Western Australian state division of the Heart Foundation included reducing sitting time in a 2009 statewide mass media campaign for obesity prevention. In the state of Queensland, Health Promotion Queensland (a cross-departmental body) commissioned an evidence-based review in 2009 on health impacts and interventions to reduce workplace sitting, with a view to future practical initiatives. Thus, there are growing expectations in Australia that too much sitting is a real and substantial risk to health. However, it remains to be seen whether the science of sedentary behavior will deliver consistent new findings in all of the research areas that are needed to inform such innovations (Fig. 4).

Given the consistency of research findings reported thus far on sedentary behavior and health, we expect that in the near future there will be a stronger body of confirmatory evidence from prospective studies and intervention trials. Furthermore, we predict that the next iteration of the Physical Activity and Public Health recommendations of ACSM/AHA will include a statement on the health benefits of reducing and breaking up prolonged sitting time.

[ CLOSE WINDOW ]

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Editor's Note
This Perspectives for Progress article is based on the corresponding author's President's Lecture from the American College of Sports Medicine's 56th Annual Meeting held in May 2009.

Acknowledgments
N. Owen is supported by a Queensland Health Core Research Infrastructure grant and by a National Health and Medical Research Council (NHMRC) Program grant funding (no. 301200; no. 569940). G.N. Healy is supported by an NHMRC (no. 569861)/National Heart Foundation of Australia (PH 08B 3905) Postdoctoral Fellowship. D.W. Dunstan is supported by a Victorian Health Promotion Foundation Public Health Research Fellowship.

Exerc Sport Sci Rev. 2010;3(3):105-109. © 2010 

 

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