Repeated Cardio Exercise Bouts Boost Fat Use

Exercise is important for weight control because it burns calories during the activity and raises metabolic rate for hours after the exercise is over. Most people trying to control their weight run on a treadmill, ride a stationary bike or work on an elliptical trainer continuously for 30-60 minutes. There may be a better way.

Japanese scientists found that two 30-minute moderate-intensity aerobics programs with a 20-minute break between sessions burned more fat than one 60-minute exercise session. The researchers compared fat use and hormone levels in people riding a stationary bicycle for 60 minutes continuously, or doing two bouts of 30 minutes separated by 20 minutes of rest between sessions. Two 30-minute bouts of exercise increased fat metabolism, stress hormone levels (i.e., catecholamines) and blood ketone levels (a marker of increased fat use) while lowering insulin and blood sugar more than the continuous 60-minute workout. Burn more fat by splitting your cardio routine.

Applied Physiology, in press; Online Published Feb. 22, 2007.