What are the benefits of HIIT

HIIT is one of the most effective workouts to burn fat.
 During high-intensity workouts, your body produces more epinephrine and human growth hormone (HGH), which both have fat-burning capabilities.
One study found that a 30-second sprint on the stationary bike resulted in a nearly 450 percent increase in HGH production. Other reported benefits of HIIT are improved insulin sensitivity and blood pressure, along with simply being an efficient way to work out with limited time in this hectic work life.

Interval training is also better at preserving lean body mass.The more muscle you have, the more calories you'll burn while at rest.
 As you get more fit, you'll increase your VO2 max, which is a number that indicates how efficiently your body uses oxygen during exercise.