Time-efficient training: comparative reviews of interval and continuous training

This was a review of earlier studies, not a new experiment. It compared interval training, short bursts of harder exercise followed by rests, with continuous training, steady exercise at one pace, in adults with different fitness levels and health backgrounds. Both approaches generally improved aerobic fitness, the body’s ability to use oxygen during exercise, and some health measures. Interval workouts often produced similar improvements in less time, but the studies used different plans and rarely tested whether either approach helped people live longer.

What this means for you: Intervals may be a time-saving option if you enjoy them and can do them safely. They were not clearly better for long-term health, so choose the type of exercise you can maintain consistently.