Why To Exercise Today: Short And Hard Lowers Blood Sugar

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So much for "I don't have time to exercise."

A new study out of McMaster University finds notable blood-sugar benefits for Type 2 diabetics from doing a mere 25 minutes of interval training three times a week, for two weeks. It was only a very small study of eight diabetics, but it fits into a growing research literature on the power of intervals — the practice of ramping up your exertion level for just a minute or two repeatedly over the course of a work-out.

And here's the most beautiful part: The major benefits came from a total of just 30 minutes a week of high-exertion training, 10 minutes per workout. Thirty minutes a week sounds like a mere moment in time compared to the interminable 150 minutes a week of moderate exercise that guidelines recommend.

Plus, in my humble opinion, intervals are fun — brief little stints of frenzy that you can ramp down as soon as the huffing and puffing starts to bother you. From the press release:

"These findings are intriguing because they suggest that exercising very strenuously for short periods of time, may provide many of the same health benefits as traditional exercise training," says Martin Gibala, professor in the Department of Kinesiology at McMaster and supervising author of the study. "This is the first study to show that intense interval training may be a potent, time-efficient strategy to improve glycemic regulation in people with type 2 diabetes."

Current guidelines from the Canadian Diabetes Association call for 150 minutes of moderate to vigorous exercise per week—twice the training time commitment of study participants—which can be tough to manage for many people including those with diabetes, adds Gibala.

He is quick to point out that larger studies are needed to comprehensively examine the potential benefits of this type of training, especially compared to traditional exercise guidelines.

For the study, researchers gave each volunteer a baseline exam to test blood sugar over a 24-hour period, assess fitness levels and take biopsies of thigh muscle to measure proteins linked to health status.

Each workout involved riding a stationary bike for 10 bouts of 60 seconds at roughly 90 percent of maximal heart rate, with one minute between each burst of exercise. The routine also included a warm up and cool down such that each training session lasted 25 minutes in total.

Participants showed improved blood sugar levels even though they did not lose weight during the short two-week study.

"The improved glycemic control may be linked to changes in the subjects' muscles, such as an improved ability to clear glucose from the blood after meals", says Gibala. "We need to conduct further research to identify the mechanisms behind these results."

This program aired on December 13, 2011. The audio for this program is not available.

Carey Goldberg Twitter Editor, CommonHealth
Carey Goldberg is the editor of WBUR's CommonHealth section.