Scientists from Maastricht University, Netherlands, published new research in the open access peer reviewed journal PLOS ONE on Feb. 13, 2013, that presents new evidence that an hour or more of daily vigorous exercise will not improve the insulin sensitivity and blood lipid levels of mostly sedentary people.
The scientists recruited eighteen normal-weight 19 to 24-year-old participants for their study. The participants followed three exercise regimes. In the first, participants were instructed to sit for 14 hours each day and not indulge in any form of exercise; the second regime required participants to sit for 13 hours each day and exercise vigorously for 1 hour; and in the third, participants substituted six hours of sitting with four of walking and two hours standing. After each regime, the researchers tracked each participant's insulin sensitivity and blood lipid levels, both of which can help identify metabolic conditions like diabetes and obesity.
Cholesterol and lipid levels improved slightly when participants exercised vigorously for an hour each day, but improved significantly when participants were active for longer periods at low intensity.
One hour of daily physical exercise cannot compensate the negative effects of inactivity on insulin level and plasma lipids if the rest of the day is spent sitting. Reducing inactivity by increasing the time spent walking or standing is more effective than one hour of physical exercise, when energy expenditure is kept constant.
Minimal Intensity Physical Activity (Standing and Walking) of Longer Duration Improves Insulin Action and Plasma Lipids More than Shorter Periods of Moderate to Vigorous Exercise (Cycling) in Sedentary Subjects When Energy Expenditure Is Comparable
Bernard M. F. M. Duvivier 1,2, Nicolaas C. Schaper 1, Michelle A. Bremers 1, Glenn van Crombrugge 1,
Paul P. C. A. Menheere 3, Marleen Kars 1, Hans H. C. M. Savelberg 2 *
1 Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands, 2 Department of Human Movement Sciences, Maastricht University Medical Centre, Maastricht, The Netherlands, 3 Central Diagnostic Laboratory, Maastricht University Medical Centre, Maastricht, The Netherlands