“This is a very time-efficient workout strategy,” said Martin Gibala, a professor of kinesiology at McMaster and lead author on the study, in a statement. “Brief bursts of intense exercise are remarkably effective.”
Gibala and his colleagues recruited 27 men living a sedentary lifestyle. They split participants into three groups and asked them to perform three weekly fitness sessions for 12 weeks, including sprint interval training and moderate-intensity continuous training. A third control group did not exercise at all. Sprint interval training involves three 20-second all-out sprints. It also includes two minutes of warm-up, three minutes of cool down, and two minutes of low-intensity cycling in between sprints for recovery.
Although moderate-intensity continuous training involved five times as much exercise and a fivefold increase in time commitment, the results after 12 weeks of training were similar among men in the all-out exercise group and the moderate exercise group. Sprint interval training improved both insulin sensitivity and endurance by 20 percent. It also boosted energy production and oxygen consumption in the men’s muscles.
“The basic principles apply to many forms of exercise,” Gibala explained. “Climbing a few flights of stairs on your lunch hour can provide a quick and effective workout. The health benefits are significant.”
The research team wanted to make it clear that neither of the fitness techniques were considered superior over the other in terms of fitness and health. The moderate fitness routine, however, took up a total of 27 hours by the end of the 12 weeks while all-out training took up six hours, including only 36 minutes of strenuous exercise.
“Most people cite ‘lack of time’ as the main reason for not being active,” Gibala added. “Our study shows that an interval-based approach can be more efficient — you can get health and fitness benefits comparable to the traditional approach, in less time.”
Now that we know what the benefits are, how is one minute of intense exercise more effective than 45 minutes of moderate physical activity? Interval training combines two of the most effective forms of exercise for burning fat: Maximum effort to achieve muscle fatigue and maximum oxygen use in a quick burst of exercise.
The point of short, high-intensity training is to push our body to the brink of VO2 max — the highest amount of oxygen it can consume during exercise. When the body gets close to this limit, the afterburn effect kicks in, meaning the body will continue to consume oxygen for up to 48 hours after the workout has ended. And for every liter of oxygen the body consumes, it has to burn five calories.
Source: Gillen J, Martin B, MacInnis M, Skelly L, Tarnopolsky M, Gibala M. Twelve Weeks of Sprint Interval Training Improves Indices of Cardiometabolic Health Similar to Traditional Endurance Training Despite a Five-Fold Lower Exercise Volume and Time Commitment. PLOS ONE . 2016.
