“The number-one cited reason for why people don’t exercise is lack of time,” says Martin Gibala, professor and chair of the department of kinesiology at McMaster University in Canada.
Gibala’s group is hunting for training regimens with the most bang (cardiovascular fitness) for the buck (your time).
Their latest: the one-minute workout.
“That’s a bit of a teaser headline,” admits Gibala. The workout consists of three 20-second all-out sprints on a stationary bike (that’s the minute) interspersed with bouts of easy cycling.
“The sprint interval workout is 10 minutes, start to finish,” says Gibala. “That includes warm-up, bouts of sprinting, recovery in between, and cool-down.” And that’s important because other high-intensity interval workouts that claim to be time savers still tend to take 25-30 minutes when you include warm-up and cool-down. That means they take no less time than the standard recommendation to walk briskly for 30 minutes.
“We were cognizant of those criticisms and we wanted to push it further,” says Gibala. “We want to know how low you can go.”
So far, the one-minute workout appears to be, well, working.
In a study of 19 sedentary young men, for example, those who did three one-minute workouts a week were just as aerobically fit after 12 weeks as those who did three 45-minute bouts of moderate cycling a week. And their insulin was just as effective in lowering blood sugar after they were given a high dose of sugar.1
So why would anyone exercise for 45 minutes, when they could get the same aerobic benefit in just 10?
Because one of those 10 minutes has to be the most intense, save-your-child-from-an-onrushing-bus kind of exertion.
“The trade-off for time is intensity,” explains Gibala. “We’re talking a ‘sprint for your life’ kind of effort.”
Many people can’t—or won’t—push themselves that hard, he notes. But, he adds, they might still be able to benefit from interval training.
For example, in one study, Thai researchers assigned 43 older adults with type 2 diabetes to a sedentary control group or to one of two exercise groups.2 Both exercise groups walked three times a week for 30 to 40 minutes. But the steady exercise group walked at a constant moderate pace, while the interval exercise group built up—over 6 weeks—to alternating walking fast for 1 minute and moderately for 4 minutes.
After 12 weeks, both walking groups were in better shape than the sedentary controls. They were more aerobically fit, their insulin worked more effectively, they had lost more body fat, and their blood vessels dilated more easily.
But hemoglobin A1c—a long-term measure of blood sugar—improved only in the interval walkers. And they had better aerobic fitness and blood vessel function than the moderate-paced walkers.
“Interval training is also beneficial in people without diabetes,” says Gibala. “If people take an interval approach, it’s probably going to be better than moderate-intensity exercise for the same time commitment.”
(Tip: If your goal is simply to burn calories, it doesn’t matter if you walk or run. Walking a mile takes more time than running a mile, but it eventually burns about the same number of calories. Looking to save time? Pick up the pace.)
“We really want to find the sweet spot between duration and intensity for different groups,” says Gibala. “The more exercise menu options we can give people, the better.”
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