December 29, 2015
Diabetes Care

TAKE-HOME MESSAGE

Postmenopausal women were evaluated while participating in either prolonged, unbroken sitting or prolonged sitting disrupted by 5 minutes of standing or light-intensity walking every 30 minutes to determine the effect on postprandial cardiometabolic markers. Both standing and walking significantly reduced the incremental AUC for glucose and insulin, and the effect continued into the next day. Compared with prolonged sitting, suppression of non-esterified fatty acids was diminished by standing and walking. There was no effect seen on the incremental AUC for triglycerides.

In postmenopausal women, standing or walking for 5 minutes intermittently during periods of prolonged sitting had beneficial effects on postprandial glucose, insulin, and non-esterified fatty acid responses, and public health interventions could encourage simple behavioral changes.

Primary Care
Written by Peter Lin MD, CCFP
Many studies have shown that sitting too much is a problem. This study evaluated 22 post-menopausal women who were at risk of developing diabetes. The first group sat for 7.5 hours. The second group had 5 minutes of walking every 30 minutes, and the final group stood up for 5 minutes every 30 minutes. Glucose, insulin, and free fatty acid levels were measured.

With walking or standing, the postprandial glucose and insulin were reduced. This hints at the idea that we may be able to prevent diabetes by having people walk or stand for 5 minutes every 30 minutes of sitting.

Also, since standing was almost as good as walking for 5 minutes, perhaps standing is all that we need to get these benefits. This could easily be adopted by corporate America because employees can still be productive while standing at their desks and still have benefits of reduced glucose and insulin levels. This is a practical way to improve health while maintaining productivity.

As for how this works, that is all speculation. I believe that it’s like the screen-saving on your computer. When your legs do not move (ie, when you are sitting), your body conserves energy by sending less blood to your legs. Less blood means you are burning less glucose, hence glucose levels increase and your insulin levels need to go up. If you move your legs just by standing, then that is like shaking the mouse to wake up your computer. Your body increases blood flow to the legs, hence you burn more glucose and your insulin levels come down.

So, perhaps moving the legs is all we need to do and we don’t even have to stand up. Bottom line is shake the mouse (leg) and keep that screen saver from kicking in.

Abstract

OBJECTIVE

To determine whether breaking up prolonged sitting with short bouts of standing or walking improves postprandial markers of cardiometabolic health in women at high risk of type 2 diabetes.

RESEARCH DESIGN AND METHODS

Twenty-two overweight/obese, dysglycemic, postmenopausal women (mean ± SD age 66.6 ± 4.7 years) each participated in two of the following treatments: prolonged, unbroken sitting (7.5 h) or prolonged sitting broken up with either standing or walking at a self-perceived light intensity (for 5 min every 30 min). Both allocation and treatment order were randomized. The incremental area under the curves (iAUCs) for glucose, insulin, nonesterified fatty acids (NEFA), and triglycerides were calculated for each treatment condition (mean ± SEM). The following day, all participants underwent the 7.5-h sitting protocol.

RESULTS

Compared with a prolonged bout of sitting (iAUC 5.3 ± 0.8 mmol/L ⋅ h), both standing (3.5 ± 0.8 mmol/L ⋅ h) and walking (3.8 ± 0.7 mmol/L ⋅ h) significantly reduced the glucose iAUC (both P < 0.05). When compared with prolonged sitting (548.2 ± 71.8 mU/L ⋅ h), insulin was also reduced for both activity conditions (standing, 437.2 ± 73.5 mU/L ⋅ h; walking, 347.9 ± 78.7 mU/L ⋅ h; both P < 0.05). Both standing (-1.0 ± 0.2 mmol/L ⋅ h) and walking (-0.8 ± 0.2 mmol/L ⋅ h) attenuated the suppression of NEFA compared with prolonged sitting (-1.5 ± 0.2 mmol/L ⋅ h) (both P < 0.05). There was no significant effect on triglyceride iAUC. The effects on glucose (standing and walking) and insulin (walking only) persisted into the following day. CONCLUSIONS Breaking up prolonged sitting with 5-min bouts of standing or walking at a self-perceived light intensity reduced postprandial glucose, insulin, and NEFA responses in women at high risk of type 2 diabetes. This simple, behavioral approach could inform future public health interventions aimed at improving the metabolic profile of postmenopausal, dysglycemic women. Story Source
Journal Abstract