It sounds like a dubious exercise regimen promoted on a late-night infomercial, but there is actual science behind it. A recent study suggests that one minute of vigorous exercise can be just as effective for improving health as 45 minutes of moderate-intensity exercise.
Researchers asked nine previously sedentary young men to do one total minute of high-intensity cycling on a stationary bike three times a week for 12 weeks. The minute was broken down into three 20-second bursts of maximum effort, with two-minute recovery periods of moderate-intensity cycling in between.
Another group of 10 men undertook a more traditional workout consisting of 45 minutes of continuous, moderate-intensity cycling three times a week, and six men did not exercise at all.
At the end of 12 weeks, the researchers found similar gains between the high-intensity and moderate-intensity groups, compared with the no-exercise group, in terms of better blood sugar control and improved endurance and muscle function.
"This study is a relatively extreme example that shows the effectiveness of brief, very intense bursts of exercise," said Martin J. Gibala, professor of kinesiology at McMaster University in Ontario.
The one-minute approach is "the most intense flavor of interval training," an approach that alternates between all-out exercise and less-intense activities, said Gibala, who led the study
(PDF), which was published in April in the journal PLOS ONE.
The new study found that high- and moderate-intensity workouts also were associated with similar amounts of modest weight loss and boosts in calorie burning, Gibala said. However, the most important way to lose weight is "on the energy-in side of the equation, what we put in our mouth," he added.
During the three 20-second bursts of activity, the researchers asked the men to ride the bike as if they were sprinting from danger. "It is about as hard an effort as you can imagine," Gibala said. The researchers measured the participants' power output to assess whether they were pushing themselves as hard as they could.
But the sprinting was only part of a workout that lasted 10 minutes from start to finish. It went like this: Two-minute warmup on the bike; 20-second high-intensity pedaling; two-minute moderate-intensity recovery; 20-second high-intensity pedaling; two-minute moderate-intensity recovery; 20-second high-intensity pedaling; three-minute cool-down on the bike. The moderate-intensity workout also involved a two-minute warmup and three-minute cool-down.
It could be hard to design an effective workout that is any faster, Gibala said. You need the recovery periods because it would be difficult to push your body to its limit for 60 seconds straight. And the warmup and cool-down periods are important for preparing your body and preventing injury.
"I think we are getting down to the bottom in terms of the number of minutes of exercise in order to get some benefits," Gibala said.
There has been a "flurry of interest" over the past 10 years in comparing high-intensity interval training with moderate-intensity exercise, he said. Although previous research
, some by Gibala and his colleagues, suggested that the high-intensity approach was similarly effective, the current study is the first to go as low as 10 minutes total.
No pain, no gain
There is probably a price to pay for a 10-minute workout. What people may gain in time, they could make up for in terms of pain.
"At the end of the day, there is a tradeoff between intensity and duration. There is no such thing as a free lunch. If people want to derive the benefits of [a short amount of] exercise, they need to go hard," Gibala said.