For many of us, the typical gym workout consists of logging an hour jumping from machine to machine, and barely breaking a sweat. It's no wonder that with this kind of boredom and results, so many people find excuses to avoid working out. Carving out time to exercise after work is hard enough but to spend it running in place on a monotonous treadmill while watching reruns or the local new? No thanks!

But what if you could cut your gym time down to 20 minutes and that time was spent in a challenging way that actually increases your fitness level? It's possible with an approach known as High Intensity Interval Training (HIIT).

Recent research findings suggest short, vigorous workouts can provide surprisingly strong health benefits. The journal, Applied Physiology, Nutrition, and Metabolism, describes HIIT as "a compromise between time-consuming, moderate-intensity training and sprint-interval training requiring all-out effort." Partaking in this form of concentrated training alternates between periods of short, intense, exercise and less-intense periods intended for recovery.

Gilaad Cohen, NSCA-CPT, head coach and owner of CrossFit Newton in Waltham, Massachusetts, says HIIT provides both physiological and mental benefits. "Training at such high intensities increases aerobic and anaerobic capacity. You will experience increases in muscle stamina and cardiovascular endurance." HIIT also packs an emotional appeal. "HIIT enthusiasts get an overall sense of accomplishment because they're pushing themselves to their limits, albeit over a short period of time," Cohen explains. "You're out of breath. Your muscles are fatigued and you feel great knowing you've done a lot of hard work."

So what does HIIT look like? Just about any exercise can be performed in high intensity intervals. They key is working in cool-down periods, which allow your body to recover before taking on the next HIIT challenge. HIIT "can be done with hand weights or dumbbells, using your own body weight or through a series of sprints. The exercises can be combined or done alone. The possibilities are endless," explains Cohen.

The HIIT Method Basics

The concept of high intensity training is really nothing new—the basics have been around for a while—but it's particularly well suited to today's frenzied pace. Two exercise researchers primarily developed HIIT fitness.

The Tabata Protocol. Based on the findings of Professor Izumi Tabata, and originally used by the Japanese Olympic Speed Skating Team, Tabata training boosts your metabolism and gets the heart rate up in a matter of second. It requires the athlete to perform 20 seconds of full output followed by 10 seconds of rest. This cycle is repeated eight times for a total of four minutes. Who can't find 4-minutes for fitness?

The Gibala Technique. Named for another research guru, Canadian Martin Gibala, this HIIT method utilizes a slightly different time scheme than Tabata. After a three-minute warm-up, athletes partake in 10 cycles of minute-long bursts of approximately 60 percent effort.

The Limitations of HIIT

HIIT helps increase cardiovascular output and, as another study cited in the journal Applied Physiology, Nutrition, and Metabolism states, it will help speed your metabolism. But there is a downside. Because it seeks to build muscle endurance, muscle strength is gained in limited amounts. And for those with heart issues, cardiovascular disease, or who are pregnant consulting a doctor before taking on a high intensity exercise regime is important, Cohen says.

Ben Greenfield, MA, reviewed this article.




Applied Physiology, Nutrition, and Metabolism. Volume 33, Number 6, Dec. 2008 , pp. 1112-1123(12)

Hood, MS; Little, JP; Tarnopolsky, MA; Myslik, F; Gibala, MJ (Oct 2011). "Low-volume interval training improves muscle oxidative capacity in sedentary adults." Med Sci Sports Exerc. 43(10): 1849-56.

US National Library of Medicine. National Institutes of Health
Appl Physiol Nutr Metab. 2008 Dec;33(6):1112-23.  doi: 10.1139/H08-097.

"Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2 max."

Med Sci Sports Exerc. 1996 Oct; 28(10):1327-30.