High-intensity interval training, known as HIIT, has been scoring one scientific victory after another, and I am excited to share two new study findings that I hope will excite you as much as they did me. HIIT involves brief (generally 30 seconds) yet very intense aerobic activity alternating with 3-4 minutes of very light activity – typically performed for about 20-25 minutes. In the first study, researchers had a small group of overweight adults take part in a four-month exercise program involving two days of HIIT training on a stationary bike along with two days of resistance training. Prior to and after the study period, the participants underwent a series of tests including measurements of body fat, brain function, and brain oxygenation. After completing the study, participants experienced several important benefits including a reduction in visceral/trunk fat (the deadly type), improvements in intellectual function, enhanced brain oxygenation, and increased insulin sensitivity (the key to a speedy metabolism). (1)
In the second study, scientists measured the total calories burned over 24 hours in a group of healthy males after a single episode of HIIT exercise and after no exercise. Specifically, they had the study subjects pedal a stationary bike as hard as they could for 30 seconds followed by four minutes of light (no resistance) pedaling for a total of just under 25 minutes. Relative to the day with no exercise, the subjects burned 200 additional calories over the course of the next 24 hours after their HIIT cycling. In other words, for just three minutes of intense exercise, the study subject significantly increased the calories they burned over the rest of the day. (2)
Based on the compelling studies I have reviewed about HIIT, I have now incorporated this super time-efficient and highly effective form of exercise in my life twice a week. Before you take up HIIT – be sure to talk to your healthcare provider to be sure it is safe for you.
1: Canadian Cardiovascular Congress Meeting, Toronto Canada October 2012
2: Integrative Biology of Exercise VI Meeting Westminster, Colorado, October 2012