Many high-performance athletes use interval training as a way to maximize their fitness, from runners to swimmers and cyclists. The strategy is to alternate between periods of high intensity and lower intensity training. NPR's Alison Aubrey reports on new research that finds this strategy can be useful for lots of us, even those who just want to get the most out of their time on a treadmill.

ALISON AUBREY, BYLINE: I often start my day on a bike right here - a stationary bike that's set up right here in my bedroom. My kids are getting ready for camp. It's kind of easy on this setting. The resistance is only at two. So the question is, should I dial it up?

TIM CHURCH: Yeah, absolutely. There is absolutely a benefit to interval training whether you're a weekend warrior, a high-performance athlete or just someone trying to get physically fit.

AUBREY: That's Tim Church. He directs exercise research at the Pennington Biomedical Research Center in Baton Rouge.

CHURCH: There are a number of studies which have shown that when you increase the intensity in the form of doing intervals, there is additional benefit beyond just the calories burned for that amount of exercise.

AUBREY: So this is what it looks like. I'm just going to dial it up from a resistance setting of two all the way up to about seven.

Compared to evenly paced exercise, the interval approach has been shown to be more effective in helping people lower cholesterol and lose weight. And now a new study published just this week finds that even when you're walking, alternating between a brisk pace and a leisurely pace - that can help control blood sugar. Thomas Solomon at the University of Copenhagen is the lead author. He conducted a four-month-long experiment. Middle-aged volunteers in their late 50s and early 60s, all of whom had type two diabetes, agreed to walk for an hour each day. Some were instructed to do interval walking - three minutes fast, three minutes slow. And another group was told to walk at a steady pace for the same amount of time. Their blood sugar control was assessed at the beginning and then at the end of the study.

THOMAS SOLOMON: What we expected to see originally, actually, was that both exercising groups would have an improvement.

AUBREY: But that's not what happened. Only the interval walkers lowered their blood sugar. The continuous walkers saw no benefit.

SOLOMON: This was, I suppose, somewhat surprising considering that they were doing one hour of exercise a day for four months.

AUBREY: But researcher Tim Church says he can understand why this may have happened. He explains that when we alternate the intensity of aerobic exercise to include these intense periods, we're working our muscles harder, and as a result, our muscles need more fuel in the form of glucose.

CHURCH: It's interesting. When you talk about diabetes, we often think about the pancreas, but the largest consumer of blood sugar in the human body is skeletal muscle. So when you do things that increase the skeletal muscle's ability to utilize more blood sugar, you're pulling excess sugar out of the blood which results in healthier blood sugar levels.

AUBREY: So I'm cycling a lot harder now. The bike is telling me my heart rate's at about 132.

And I'm feeling it. So even if you're not worried about blood sugar, this interval approach, to me, sure feels like a good workout. Alison Aubrey, NPR News.

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