HEALTH TOPICS 
Wondering whether interval training is the best way to enhance your workout? Interval training simply means alternating between short bursts of intense exercise and brief periods of rest (or less-intense activity). The payoff is improved cardiovascular fitness.
"Aerobic or cardiovascular training is designed to develop a healthier heart and circulatory system," explains Howard Knuttgen, research associate in physical medicine and rehabilitation at Harvard-affiliated Spaulding Rehabilitation Hospital, in the September 2015 issue of the Harvard Men's Health Watch. "Some regimen of aerobic training is really essential to good health."
Interval training requires the person to exercise for very brief periods at a higher intensity or velocity than he or she could otherwise sustain for five to 10 minutes before becoming exhausted, Knuttgen says. Here are a few ways to turn a typical moderate-intensity workout into a session of interval training:
Swimming. Swim one lap as fast as possible. Rest for about the same time as it took to swim the lap. Repeat.
Walking. Walk as fast as possible for a minute or two. Then walk at a leisurely pace for the same period. Repeat.
Gym machines. Treadmills, elliptical trainers, and stationary bicycles often have a built-in interval training function to put gym-goers through their paces.
Read the full-length article: "Interval training for a stronger heart"