Breaks in prolonged sitting reduce cardiovascular risk and obesity

A valuable study recently published in the journal Diabetes Care offers evidence that breaking up prolonged sitting markedly improves glucose and insulin regulation to reduce cardiovascular risk and obesity. The authors went beyond observational studies to see measure the effects of a calibrated intervention:

"We examined the acute effects on postprandial glucose and insulin levels of uninterrupted sitting compared with sitting interrupted by brief bouts of light- or moderate-intensity walking."

They recruited 19 overweight for a randomized crossover trial during which the subjects cycled through 1) uninterrupted sitting; 2) sitting with 2 minutes of light walking every 20 minutes; and 3) sitting with 2 minutes of moderate intensity walking every 20 minutes. They then gave a standard glucose test drink of 75 grams of glucose and 50 grams of fat after another 2 hours of uninterrupted sitting, after which they measured blood glucose and insulin dynamics (the incremental area under curves (iAUC) for glucose and insulin). The difference was very impressive:

"The glucose iAUC (mmol/L) ⋅ h after both activity-break conditions was reduced (light: 5.2; moderate: 4.9) compared with uninterrupted sitting (6.9). Insulin iAUC (pmol/L) ⋅ h was also reduced with both activity-break conditions (light: 633.6; moderate: 637.6 ) compared with uninterrupted sitting (828.6)."

Outstanding. Just by getting up and moving around for a couple of minutes there was a very significant improvement in the regulation of glucose and insulin. These are, of course, major driving factors for cardiovascular risk and obesity; but they also play an important role in a multitude of conditions that involve chronic inflammation. This is such a simple and risk-free intervention—all clinicians should be recommending brief periods of movement to patients whose work requires extended periods of stationary activity. The authors conclude:

"Interrupting sitting time with short bouts of light- or moderate-intensity walking lowers postprandial glucose and insulin levels in overweight/obese adults. This may improve glucose metabolism and potentially be an important public health and clinical intervention strategy for reducing cardiovascular risk."

In addition to the 2 minute periods of walking described in this study I can offer anecdotal evidence for the benefit of a work day spent standing with intermittent periods of sitting. This is permitted by desks that easily adjust between standing and sitting configurations. Prolonged sitting feels very sluggish compared to the invigorating effects of working while standing.