Exercise has been shown to reduce obesity and related glucose tolerance, but whether increasing exercise intensity improves outcomes has not been determined. Researchers studied 300 abdominally obese adults to determine the separate effects of exercise amount and intensity on abdominal obesity and glucose tolerance. Participants were randomly assigned to perform either short, high intensity workouts or long, lower intensity workouts five times a week. All participants were instructed to eat a healthy diet during the study but did not reduce their caloric intake. After 24 weeks, all participants experienced similar reductions in waist circumference, but only participants in the high intensity exercise group experienced reduction in two-hour glucose levels.
According to lead study author, Robert Ross, PhD, of the School of Kinesiology and Health Studies at Queen's University in Kingston, Ontario, the results show a clear benefit to higher intensity workouts for those who wish to reduce glucose levels. For those who may think that high intensity workouts are too difficult, Dr. Ross has good news. "Higher intensity can be achieved simply by increasing the incline while walking on a treadmill or walking at a brisker pace," he said. "Participants were surprised by how easy it was for them to attain a high intensity exercise level."
Article: Effects of Exercise Amount and Intensity on Abdominal Obesity and Glucose Tolerance in Obese Adults: A Randomized Trial, R. Ross, R.H. MD, P.J. Stotz, and M. Lam, Annals of Internal Medicine, doi: 10.7326/M14-1189, published 2 March 2015.