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High-Intensity Interval Training: Your Guide to Fast, Effective Exercise

Private: Elizabeth G. Matzkin, MD
Contributor Elizabeth G. Matzkin, MD

What is high-intensity interval training?

High-intensity interval training (HIIT) is a form of exercise in which short periods of intense exercise are alternated with less intense recovery periods. It also may be called high-intensity intermittent exercise (HIIE), sprint interval training (SIT), or Tabata (after the professor who studied this type of training in Olympic speed skaters).

Any form of cardiovascular exercise can be used to develop a HIIT program. A session usually lasts from five to 30 minutes, and intervals can range from five seconds to eight minutes. The high-intensity interval should be performed at 80 to 95 percent of your maximal hear rate. Recovery periods should be performed at 40 to 50 percent of your maximal heart rate. The workout then continues with alternating high-intensity and recovery periods until completion.

Why is it popular?

HIIT programs can deliver excellent fitness gains with modest time investments. This helps make HIIT popular with people who have limited time to exercise or limited interest in exercising, as well as athletes who want to efficiently maximize their athletic capacity. Along with helping to increase speed, strength, and endurance, the high-intensity bursts of exercise lead to significant calorie burn – especially during the approximately two hours of rest after exercise.

HIIT is also popular because of its flexibility. It can be done with brisk walking, running, swimming, biking, elliptical, or any other type of exercise that can sufficiently elevate your heart rate.

What are some examples of HIIT?

  • Run at high intensity for 30 seconds and then recover for 30 seconds (1:1 ratio).
  • Run at high intensity for one minute and then recover for three minutes (1:3 ratio).
  • Bike at high intensity for 45 seconds and then recover for 90 seconds (1:2 ratio).

Almost any combination of intense exercise and recovery you can think of can constitute a HIIT program, and every program can be modified to suit the individual. It can be modified according to someone’s fitness level, the amount of time available for training, exercise preference, and desired intensity level.

Interval training is a great way to optimize fitness, so talk to your doctor about whether it would be safe for you to start a HIIT program.

Private: Elizabeth G. Matzkin, MD
Elizabeth G. Matzkin, MD

Elizabeth G. Matzkin, MD, is Surgical Director of the Women’s Sports Medicine Program at Brigham and Women’s Hospital, Team Physician for Stonehill College Athletics, and Assistant Professor of Orthopaedic Surgery at Harvard Medical School.

Before you go,

Staying active through regular exercise and playing sports offers many physical and mental health benefits. Get tips on how to optimize your workouts and keep your body safe from injury. Read more exercise and sports articles.