What’s the most beneficial type of exercise? The answer is interval training, and you don’t need much of it at all to maintain good health and fitness. Interval training is a type of workout that consists of an extremely draining but brief burst of exercise—a sprint—followed by light exercise such as jogging or resting, then another sprint, more rest, and so on. A new study of interval training shows that you need very little of it for good results. In fact, the study shows that 60 seconds of strenuous exertion proved to be as successful at improving health and fitness as three-quarters of an hour of moderate exercise.