Effect of Higher-Intensity Exercise on Weight Loss and Waist Circumference

From Annals of Internal Medicine, American College of Physicians

What is the problem?
Obesity is an important and prominent risk factor for diabetes, which is a disease that increases the risk for cardiovascular disease. While researchers know that exercise is important to help reduce waist circumference and improve cardiovascular health, the effects of high-intensity exercise are still not solidified. The researchers conducted this particular study in order to determine whether it makes a significant difference if an exercise regimen involving the same total amount of exercise is completed at a lower or higher intensity.

How was the study completed?
The researchers gather 300 adults with abdominal obesity, who did not currently have diabetes. They were then randomly assigned to complete five exercise sessions each week that involved either a lower or higher total amount of low- or high-intensity exercise. A trainer supervised each session in order to monitor the amount and intensity of exercise. Throughout the study, researchers measured: waist size, weight, cardiovascular fitness and the body’s response to blood sugar.

What did the researchers find?
Compared to the control group, which was asked not to engage in any structured exercise, each exercise group reduced wait circumference and greater reduction in body weight. According to the study, performing the same amount of exercise at a higher intensity did not result in a significantly greater reduction in waist size or more weight loss. However, the participants in the high-intensity exercise group did have a greater increase in cardiovascular fitness and there was an improvement in how well the body controls blood sugar.
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The research conducted suggests that waist size may be reduced by both low and high intensity exercise as long as the same amount of exercise is performed (i.e. walking the same distance in either 60 or 40 minutes). While this research is enlightening, it is still unknown what the long-term health benefits are of the improved blood sugar control seen in people without diabetes.