“I don’t have the time to exercise” can no longer be an excuse. A single minute of very intense exercise per week can produce similar health benefits as 45 minutes of continuous, moderate-intensity cycling a week, a study found. Even the one minute exercise was split into three short bouts of 20 seconds separated by two minutes of low-intensity cycling. The results were published on April 26 in PLOS ONE.
Jenna B. Gillen, the first author of the paper from McMaster University, examined key health indicators including cardiorespiratory fitness and insulin sensitivity, a measure of how the body regulates blood sugar, to see the difference in exercise duration and intensity and health benefits.
For the 12-week study, 27 sedentary men were recruited and assigned to perform three weekly sessions of either intense or moderate training; a control group did not exercise.
The intense cycling — sprint interval training (SIT) — protocol involved three 20-second “all-out” cycle sprints. The volunteers warmed up for two minutes and then pedalled hard for 20 seconds and then pedalled slowly for two minutes and then repeated the cycle of hard pedalling and slow pedalling two more times. At the end the three 20-second bouts, the volunteers cooled down for three minutes. The entire workout duration lasted only for 10 minutes.
Volunteers in the moderate-intensity continuous training (MICT) group warmed up for two minutes and then pedalled continuously for 45 minutes and then cooled down for three minutes. The entire duration of exercise lasted 50 minutes.
Cardiorespiratory fitness
At the end of the study, brief but intense exercise improved cardiometabolic health to the same extent as traditional endurance training in sedentary men, despite the duration of exercise and time spent being five times lesser, the study found. Though it was known that brief hard workout increased cardiorespiratory fitness, there has been no study to conclusively prove it by comparing it with long-duration moderate exercise.
While an earlier study found that low-intensity exercise for 150 minutes per week for over 24 weeks may not be sufficient to improve cardiorespiratory fitness of many adults, the present study found that in sedentary adults, a meagre three minutes of exercise per week of short, intense burst of exercise within 30 minutes duration over 12 weeks can bring significant improvement.
The researchers are not sure of the precise mechanism that is responsible for the improvement in both the arms that did exercise.
Insulin sensitivity
Similarly, the insulin sensitivity index increased 53 per cent in those doing intense exercise compared with 34 per cent for those exercising for 45 minutes per session.
Earlier studies have shown that for a given energy expenditure, higher-intensity exercise confers greater benefits than moderate-intensity exercise, especially in people with obesity, metabolic disorders, and Type 2 diabetes. The present study strengthens this observation.
Compared with the control group, both the groups that exercised improved their peak oxygen uptake by 12 per cent after six weeks of exercising. The peak oxygen uptake increased to 19 per cent after 12 weeks of training versus pre-training. Though body mass remained for people in all the three groups (two exercise groups and control), there was a reduction in the percent body fat in people who exercised.
“If you are an elite athlete, then obviously incorporating both endurance and interval training into an overall program maximizes performance. But if you are someone, like me, who just wants to boost health and fitness and you don’t have 45 minutes or an hour to work out, our data show that you can get big benefits from even a single minute of intense exercise,” Martin J. Gibala, the senior author told The New York Times.
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