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Why Does HIIT Work? It’s Backed By Science.

Fitness • April 29, 2019

High-intensity interval training, or HIIT, is the most effective and efficient way to exercise. With short bursts of intense exercise, alternated with low intensity recovery periods, HIIT workouts provide maximum health benefits in minimal time.

HIIT can burn a lot of calories in a short amount of time. Simply put, you can burn calories quickly using HIIT. In one study, HIIT was compared to weight training, running and biking. Researchers have found that HIIT burned 25-30% more calories than the other forms of exercise. A HIIT repetition consisted of 20 seconds of maximal effort, followed by 40 seconds of rest. This means the participants were only exercising for 1/3 of the time that the running and biking groups were. Although each workout session was 30 minutes long in this study, it is common for HIIT workouts to be much shorter than other (more traditional) exercise sessions. HIIT allows you to burn about the same amount of calories, but spend less time exercising.  

Your metabolic rate is higher for hours after exercise. In a recent study, HIIT was found to shift the body’s metabolism toward using fat for energy rather than carbs. Another study showed that just two minutes of HIIT in the form of sprints increased metabolism over 24 hours as much as 30 minutes of running.

It helps you lose fat. High-intensity intervals can produce similar fat loss to traditional endurance exercise, with a much smaller time commitment. That means you can burn fat while spending less time at the gym!

HIIT will keep you young. Let’s take things one level deeper (literally). HIIT has even been proven to halt aging at the cellular level. According to a 2017 study, HIIT has been shown to increase production of proteins in the mitochondria, the part of your cells that release energy. Typically, these proteins deteriorate over time, but strength training and HIIT has been proven to reverse this process.  

Ready to get into HIIT? There are plenty of ways to add interval training to the exercises you’re already doing. For example, if you’re a runner, try adding short 30 second sprints into your jogs. If you prefer group exercise, classes like our Signature FHIT class are a great way to test drive HIIT since they allow you to practice proper form and technique under the guidance of a certified instructor. Once you practice more high-intensity intervals over time, just see if you don’t notice a difference in your body and its power!