High intensity interval training (HIIT) is only effective for improving fitness when performed at 60-second intervals, according to new research from Liverpool John Moores University.
Specifically, home-based HIIT, which involves doing HIIT training at home using simple body weight exercises, has become popular because it gets rid of the barriers such as the time and money required to go to the gym.
Researchers compared two popular HIIT protocols (60HIIT and 30HIIT) performed for six weeks, three times per week, in a sample of 26 previously sedentary men and women. 60HIIT means 6-10 60-second intervals with 60 seconds of rest, whereas 30HIIT means 4-8 30 seconds intervals with 120 seconds of rest.
The researchers looked at three parameters of fitness: aerobic capacity, stiffness of arteries, and body composition (meaning how much muscle and fat they had) during the six weeks of HIIT.
Aerobic capacity increased after six weeks of 60HIIT but there was no difference for 30HIIT on any of the three parameters.