People who are already in shape may need only a few minutes of intense exercise a week-not a couple of hours-to stay in shape, according to a Canadian study published in the June issue of Journal of Applied Physiology. The researchers noted that the type of high-intensity exercise performed in the study may be safe only for those who are already fit, says an article in HealthDay News.

In the study of 23 fit and active people, researchers at McMaster University in Hamilton, Ontario, concluded that 6 minutes of intense exercise per week can provide the same benefits as six hours of moderate exercise, and the short sessions improved muscle capacity and endurance, BBC News reported.

The study volunteers were divided into three groups performing different training programs three rimes a week. Group one cycled for 2 hours a day at a moderate pace; Group 2 cycled for 10 minutes a day in 60-second spurts at a slightly harder pace; and Group 3 cycled at top speed for 2 minutes in 30-second spurts, resting for 4 minutes between each sprint.