Reduced Activity Has Negative Metabolic Consequences
Adverse changes in plasma insulin, increased intra-abdominal fat occur within two to three weeks
TUESDAY, March 18 (HealthDay News) -- In healthy, young non-exercising men, a significant reduction in the number of steps taken per day quickly results in adverse metabolic changes that could set the stage for diabetes and heart disease, according to a research letter published in the March 19 issue of the Journal of the American Medical Association.
Rasmus H. Olsen, M.D., of the University of Copenhagen in Denmark, and colleagues conducted two sub-studies, the first of which involved eight men who reduced their pedometer-recorded daily steps from a mean value of 6,203 to 1,394, and were assessed at baseline and after seven, 14 and 22 days. The second study involved 10 men who reduced their daily steps from a mean value of 10,501 to 1,344 and were assessed at baseline and after 14 days. In both groups, the men were told to reduce daily steps by taking elevators instead of stairs and riding in cars instead of walking or bicycling.
In the first group, the researchers found that plasma insulin areas under the curve (AUC) increased from 757 pmol/L/3h to 1,352 pmol/L/3h after three weeks. In the second group, they found that plasma insulin AUC increased from 599 pmol/L/3h to 942 pmol/L/3h and that plasma C-peptide AUC increased from 4,310 pmol/L/3h to 5,795 pmol/L/3h after two weeks. The investigators also found that subjects in group two had a 7 percent increase in intra-abdominal fat mass.
"They developed metabolic changes suggestive of decreased insulin sensitivity and attenuation of postprandial lipid metabolism, and physical changes that suggest that calories used to maintain muscle mass with greater stepping may have been partitioned to visceral fat," the authors conclude. "If confirmed, these abnormalities could represent a link between reduced exercise and the risks that have been associated with the progression of chronic disorders and premature mortality."