1 Minute of All-Out Exercise May Have Benefits of 45 Minutes of Moderate Exertion, by Gretchen Reynolds.

For many of us, the most pressing question about exercise is: How little can I get away with? The answer, according to a sophisticated new study of interval training, may be very, very little.

In this new experiment, in fact, 60 seconds of strenuous exertion proved to be as successful at improving health and fitness as three-quarters of an hour of moderate exercise.