The Upside of All-Out Intervals

Good news for time-crunched exercisers: One minute of intense interval training may provide the same benefits as 45 minutes of moderate exercise.

Researchers at Ontario’s McMaster University divided 25 out-of-shape men between the ages of 19 and 35 into three groups. One continued their sedentary habits. Another rode stationary bicycles for moderate 45-minute sessions three times a week. The final group’s thrice-weekly workouts included three all-out 20-second cycling sprints separated by two minutes of low-intensity cycling; their entire workout lasted 10 minutes, with only one strenuous minute.

After 12 weeks, they tested the subjects’ aerobic fitness, muscle development, and insulin resistance, and found that the endurance and interval groups showed virtually identical gains.