How HIIT Works
High Intensity Interval Training can deliver a host of health benefits. A significant body of research confirms HIIT's effectiveness to:
Burn More Calories: Two published studies found that HIIT burns more calories in the same amount of time than other types of exercise. The research was performed at California State University, San Marcos, and University of Colorado, Denver, respectively.
And then Burn Some More: After finishing a HIIT workout, the body continues to burn more calories than other exercise formats … even when you're resting! This metabolic boost from HIIT has been documented in multiple published studies from sports scientists in Singapore, Ontario, and Chapel Hill.
Burn Fat: After 12 weeks, adults had "significant reductions in abdominal fat" from HIIT workouts with no change in diet. The workouts took 20 minutes each, three times a week. The study documented a 17% decrease in visceral fat, the kind that surrounds internal organs and has been linked to many diseases. Other studies confirm that HIIT promotes fat loss with a surprisingly low time commitment.
Lower Blood Pressure: Overweight and obese people can lower their blood pressure with HIIT workouts – that's according to a review of 65 published studies.
Release More Endorphins: They're the hormones that kill pain and give us a natural high. When you engage in HIIT workouts, your body naturally releases more of them than when you do moderate exercise, according to a 2017 article in the journal Neuropsychopharmacology (say that three times fast!)
Making It Your Own
Of course, a HITT workout should be intense … within your personal limits. The goal is to build fitness as well as confidence. You should feel invigorated after a HIIT workout, not defeated.
If you're new to HIIT, start slowly. Just add a few 15 or 30-second higher-intensity intervals to your existing cardio workout. Maybe your "higher" is someone else's "moderate"; that's fine. As you build your confidence and fitness level, you can add more intervals, raise the intensity, or reduce the length of the low-intensity/walking interval.
And keep it short; experts consistently recommend that HIIT workouts last 30-minutes or less, just two or three times a week at most; the intensity of these workouts can put you at risk of overuse injuries. With HIIT, a little goes a long way.
