Today it is common to have a job that involves sitting at a desk for eight hours a day. And usually we would feel good if we hit the gym a few times a week, or managed to squeeze in a hike on a weekend. However, one major lesson that has come out of research on sedentary behavior is that exercising before or after work—although great to do – does not undo the harm done by sitting all day. Long periods of sitting are associated with a greater risk of diabetes, cardiovascular disease, cardiovascular and all-cause mortality, colon, endometrial and lung cancers. 1, 2 3
Even if you exercise daily, long periods of sedentary time, whether sitting at a desk at work or on the couch in front of the television, can have negative effects on your health. While this is troubling news for those of us with office jobs, there are some easy ways to counteract the dangers of sitting. Research has found that simply interrupting sitting time with standing or walks may prevent the negative health effects of a sedentary job.
Take Every Opportunity to Move
A short period of sitting—five consecutive hours – increased insulin resistance compared to five hours of sitting interrupted every 20 minutes with a two minute walk. In the study, participants consumed a 760-calorie meal followed by five hours of sitting, and then the next day did the same but broke up the five hours of sitting with two minute walks every 20 minutes. The results showed a more than 20 percent decrease in plasma glucose and insulin levels on the day with walking interruptions. 4
Another study compared a single block of 30 minutes of walking to a total of 30 minutes of walking spread out over a day of sitting. In this study, 70 healthy, normal weight adults did each of these three different patterns in a random order: nine hours of continuous sitting; uphill walk on a treadmill for 30 minutes followed by 8.5 hours of continuous sitting; and nine hours of sitting, interrupted by 100 second walking breaks every 30 minutes (for a total of 30 minutes of walking.) The participants were given three meals each day of the experiment. Researchers found that regular walking breaks reduced plasma glucose by 37 percent and plasma insulin by 18 percent. The most notable result was that regular walking breaks totaling 30 minutes of physical activity produced greater reductions in plasma glucose and insulin than the 30 minute block of physical activity.5
Get On Your Feet
The important message here is that even very light activity can help to counteract the dangers of sitting, as long as you interrupt your periods of repose with frequent bouts of movement. For optimal health, avoid prolonged, uninterrupted sitting time. Try standing for a significant portion of your day using a sit-to-stand desk. An active workstation allows for muscle activity.6 When we stand, we naturally shift weight and move around. Standing while working—and alternating standing and sitting – have been found to reduce plasma glucose levels compared to sitting alone. 7, 8
Even Light Activity Makes a Big Difference
- Even if you use a sit-stand desk, it is still advisable to take occasional walking breaks
- Set a timer to remind you to take one to two minute walks every 30 minutes
- Take phone calls standing up
- Walk up and down the stairs a few times a day
- Walk to a colleague’s office instead of sending an email
- Wilmot EG, Edwardson CL, Achana FA, et al. Sedentary time in adults and the association with diabetes, cardiovascular disease and death: systematic review and meta-analysis. Diabetologia 2012, 55:2895-2905.
- Schmid D, Leitzmann MF. Television viewing and time spent sedentary in relation to cancer risk: a meta-analysis. J Natl Cancer Inst 2014, 106.
- Katzmarzyk PT, Lee IM. Sedentary behaviour and life expectancy in the USA: a cause-deleted life table analysis. BMJ Open 2012, 2.
- Dunstan DW, Kingwell BA, Larsen R, et al. Breaking up prolonged sitting reduces postprandial glucose and insulin responses. Diabetes Care 2012,35:976-983.
- Peddie MC, Bone JL, Rehrer NJ, et al. Breaking prolonged sitting reduces postprandial glycemia in healthy, normal-weight adults: a randomized crossover trial. Am J Clin Nutr 2013, 98:358-366.
- Hamilton MT, Hamilton DG, Zderic TW. Role of low energy expenditure and sitting in obesity, metabolic syndrome, type 2 diabetes, and cardiovascular disease. Diabetes 2007, 56:2655-2667.
- Buckley JP, Mellor DD, Morris M, Joseph F. Standing-based office work shows encouraging signs of attenuating post-prandial glycaemic excursion. Occup Environ Med 2014, 71:109-111.
- Thorp AA, Kingwell BA, Sethi P, et al. Alternating bouts of sitting and standing attenuate postprandial glucose responses. Med Sci Sports Exerc2014, 46:2053-2061.
Written By Joel Fuhrman, M.D.