It’s not just that physical activity is good for you. It’s that a sedentary lifestyle, as a totally separate variable, is seriously bad. [i] [ii] [iii] [iv] [v] [vi]
Sitting too much – all by itself – can raise the risk of disease and premature mortality, even if you dutifully exercise.[vii]In fact, many well-educated people do exercise; but they’re also more likely to have desk jobs.[viii]
A large 2012 study of 240,819 healthy American adults, for instance, showed that more time spent sitting was linked to premature death from heart disease and cancer.[ix] Even among people who exercised more than seven hours a week, watching TV for more than seven hours a day was linked to a 50 percent greater risk of all-cause mortality and a 2-fold greater risk of cardiovascular mortality.
You may be able to offset this somewhat with activity.[x] [xi] But to wipe it out completely, you have to work out hard for an hour or more every day, as a 2016 study in The Lancet showed.[xii]
That study, a meta-analysis of 13 studies involving more than 1 million people, showed, as expected, that people who sat for 8 hours a day and got almost no exercise had higher mortality rates than people who sat less and were very active. The good news was that sitting for 8 hours a day was not associated with higher death rates if people were very active – meaning 60 to 75 minutes of hard exercise a day.
Put bluntly, sitting kills. If you want a short, sickly life, just sit there, for 13 hours a day, like the average American.[xiii](In Western countries overall, adults spend 55 to 70 percent of the day – 9 to 11 hours – just sitting.[xiv])
Before you give up in despair, though, contemplate this. Replacing just two minutes of sitting every hour with a bit of moving around helps mitigate the risks of sitting. Better yet, don’t sit for more than 30 minutes at a stretch.[xv] [xvi][xvii] [xviii]
The main idea here is that sedentary behavior is not just the absence of physical activity but a distinct behavior with its own health risks.[xix] [xx] [xxi] [xxii] [xxiii]
In fact, “sedentary physiology” is now considered a separate field of research from the long-established field of “exercise physiology.”[xxiv]
Technically, sedentary behavior is defined as any waking behavior characterized by an energy expenditure less than or equal to 1.5 times the resting metabolic rate while in a sitting or reclining position. (Scientists measure activity in “METS,” or metabolic equivalents. One MET is the amount of energy it takes to sit still; moderate activity burns three to six METS; vigorous activity burns more than six.[xxv])
That’s different from physical inactivity, which is defined as not reaching the recommended 150 minutes per week of moderate intensity exercise.[xxvi]
Physical inactivity, in fact, is believed to be “the biggest public health problem of the 21st century,” says Steven N. Blair, a professor of exercise science and epidemiology/biostatistics at the University of South Carolina.[xxvii]
Indeed, physical inactivity causes as many deaths a year globally as smoking.[xxviii]
Bottom line: Don’t just giving up smoking as we head into 2020. Giving up sitting around, too. Your life depends on it.
[i] Bouchard, C., Blair, S. N., & Katzmarzyk, P. T. (2015). Less Sitting, More Physical Activity, or Higher Fitness?. Mayo Clinic Proceedings, 90(11), 1533–1540.
[ii] Proper, K. I., Singh, A. S., van Mechelen, W., & Chinapaw, M. J. M. (2011). Sedentary behaviors and health outcomes among adults: a systematic review of prospective studies. American Journal of Preventive Medicine, 40(2), 174–182.
[iii] Thorp, A. A., Owen, N., Neuhaus, M., & Dunstan, D. W. (2011). Sedentary behaviors and subsequent health outcomes in adults a systematic review of longitudinal studies, 1996-2011. American Journal of Preventive Medicine, 41(2), 207–215.
[iv] Das, P., & Horton, R. (2016). Physical activity-time to take it seriously and regularly. Lancet, 388(10051), 1254–1255.
[v] Sallis, J.F., Bull, F., Guthold, R., Heath, G.W., Inoue, S., Kelly, P….Hallal, P.C., (2016). Progress in physical activity over the Olympic quadrennium. The Lancet, 388(10051), 1325–1336.
[vi] Reis, R. S., Salvo, D., Ogilvie, D., Lambert, E. V., Goenka, S., Brownson, R. C., & Lancet Physical Activity Series 2 Executive Committee. (2016). Scaling up physical activity interventions across the globe: stepping up to larger and smarter approaches to get people moving. Lancet, 388(10051), 1337–1348.
[vii] Craft, L. L., Zderic, T. W., Gapstur, S. M., VanIterson, E. H., Thomas, D. M., Siddique, J., & Hamilton, M. T. (2012). Evidence that women meeting physical activity guidelines do not sit less: An observational inclinometry study. The International Journal of Behavioral Nutrition and Physical Activity, 9, 122.
[viii] Levine, J. (2014, November 1). Killer Chairs: How Desk Jobs Ruin Your Health, Scientific American. Retrieved from https://www.scientificamerican.com/article/killer-chairs-how-desk-jobs-ruin-your-health/
[ix] Matthews, C. E., George, S. M., Moore, S. C., Bowles, H. R., Blair, A., Park, Y., … Schatzkin, A. (2012). Amount of time spent in sedentary behaviors and cause-specific mortality in US adults. The American Journal of Clinical Nutrition, 95(2), 437–445.
[x] Katzmarzyk, P. (personal communication, August 9, 2016).
[xi] Duvivier, B.M.F.M., Schaper, N.C., Hesselink, C., van Kan, L., Stienen, N., Winkens, B. (2017). Breaking sitting with light activities vs. structured exercise: a randomized crossover study demonstrating benefits for glycaemic control and insulin sensitivity in type 2 diabetes. Diabetologia, 60 (3), 490-8.
[xii] Ekelund, U., Steene-Johannessen, J., Brown, W. J., Fagerland, M. W., Owen, N., Powell, K. E., … Lancet Sedentary Behaviour Working Group. (2016). Does physical activity attenuate, or even eliminate, the detrimental association of sitting time with mortality? A harmonised meta-analysis of data from more than 1 million men and women. Lancet (London, England), 388(10051), 1302–1310.
[xiii] Levine, J. (2014, November 1). Killer Chairs: How Desk Jobs Ruin Your Health. Scientific American. Retrieved from https://www.scientificamerican.com/article/killer-chairs-how-desk-jobs-ruin-your-health/
[xiv] Matthews, C. E., Chen, K. Y., Freedson, P. S., Buchowski, M. S., Beech, B. M., Pate, R. R., & Troiano, R. P. (2008). Amount of Time Spent in Sedentary Behaviors in the United States, 2003–2004. American Journal of Epidemiology, 167(7), 875–881.
[xv] Diaz, K.M., Howard, V.J., Hutto, B., Colabianchi, N., Vena, J.E., Safford, M.M. (2017). Patterns of sedentary behavior and mortality in U.S. middle-aged and older adults: A national cohort study. Ann Intern Med, 167 (7), 465-75.
[xvi] Beddhu, S., Wei, G., Marcus, R. L., Chonchol, M., & Greene, T. (2015). Light-Intensity Physical Activities and Mortality in the United States General Population and CKD Subpopulation. Clinical Journal of the American Society of Nephrology: CJASN, 10(7), 1145–1153.
[xvii] Reynolds, G. (2015, May 13). A 2-minute walk may counter the harms of sitting. The New York Times. Retrieved from https://well.blogs.nytimes.com/2015/05/13/a-2-minute-walk-may-counter-the-harms-of-sitting/
[xviii] Preidt, R. (2016, August 16). Even if you exercise, too much sitting time is bad. CBS News. Retrieved from http://www.cbsnews.com/news/even-if-you-exercise-prolonged-sitting-time-is-bad-for-heart-health/
[xix] Pulsford, R. M., Stamatakis, E., Britton, A. R., Brunner, E. J., & Hillsdon, M. (2015). Associations of sitting behaviours with all-cause mortality over a 16-year follow-up: the Whitehall II study. International Journal of Epidemiology, 44(6), 1909–1916.
[xx] Pate, R. R., O’Neill, J. R., & Lobelo, F. (2008). The evolving definition of “sedentary.” Exercise and Sport Sciences Reviews, 36(4), 173–178.
[xxi] Young, D. R., Hivert, M.-F., Alhassan, S., Camhi, S. M., Ferguson, J. F., … Yong, C. M. (2016). Sedentary Behavior and Cardiovascular Morbidity and Mortality: A Science Advisory From the American Heart Association, Endorsed by the Obesity Society. Circulation, 134(13), e262–e279.
[xxii] Althoff, T., Sosic, R., Hicks, J.L., King, A.C., Delp, S.L. & Leskovec, J. (2017). Large-scale physical inactivity data reveal worldwide activity inequality. Nature, 547 (7663), 366-39.
[xxiii] Dunlop, D. D., Song, J., Arntson, E. K., Semanik, P. A., Lee, J., Chang, R. W., & Hootman, J. M. (2015). Sedentary time in U.S. older adults associated with disability in activities of daily living independent of physical activity. Journal of Physical Activity & Health, 12(1), 93–101.
[xxiv] Tremblay, M. S., Colley, R. C., Saunders, T. J., Healy, G. N., & Owen, N. (2010). Physiological and health implications of a sedentary lifestyle. Applied Physiology, Nutrition, and Metabolism, 35(6), 725–740.
[xxv] Measuring Physical Activity. (2016). Harvard T.H. Chan School of Public Health. Retrieved from https://www.hsph.harvard.edu/nutritionsource/mets-activity-table/
[xxvi] Bouchard, C., Blair, S. N., & Katzmarzyk, P. T. (2015). Less Sitting, More Physical Activity, or Higher Fitness?. Mayo Clinic Proceedings, 90(11), 1533–1540.
[xxvii] Blair, S. (2009). Physical inactivity: the biggest public health problem of the 21st century. Br J Sports Med, 43, (1).
[xxviii] Lee, I.M., Shiroma, E.J., Lobelo, F., Puska, P., Blair, S.N., & Katzmarzyk, P.T. (2012). Effect of physical inactivity on major non-communicable diseases worldwide: an analysis of burden of disease and life expectancy. The Lancet, 380(9838), 219-229.
[xxix] Lee, I. M. (personal communication, July 21, 2016).
[xxx] Levine, J. (2014, November 1). Killer Chairs: How Desk Jobs Ruin Your Health, Scientific American. Retrieved from https://www.scientificamerican.com/article/killer-chairs-how-desk-jobs-ruin-your-health/
[xxxi] Lee, I.-M., Shiroma, E.J., Evenson, K.R., Kamada, M., LaCroix, A.Z., Buring, J.E. (2017). Circulation, 136 (19).
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