High intensity interval training, or HIIT as it is best known, has conquered the fitness world over the last few years.
Involving short bursts of usually between 20 seconds and 90 seconds of intense cardio exercise, it is beloved for its fat torching powers, and the fact that it essentially allows you to cut your workouts down by almost half.
Now, scientists from the Liverpool John Moores University say they have found the optimum length of time for your HIIT intervals. Their research, presented at the The Physiological Society early career conference, suggests HIIT training will only have a positive impact on fitness levels if it’s performed at 60-second intervals.
The researchers compared two HIIT protocols – 60HIIT and 30HIIT. In the study a small sample of 26 previously sedentary men and women performed one of these regularly over a six-week period. The 60HIIT workout involved six to 10 rounds of 60-second intervals with 60 seconds of rest in between, while the latter involved four to eight 30-second intervals with 120 seconds of rest.
They then compared aerobic capacity, stiffness of arteries, and body composition to asses the participants’ fitness levels after six weeks. The results showed that those who performed 60HIIT saw an improvement in their aerobic capacity increase (but nothing else), while those doing 30 HIIT saw no improvement across any of the three fitness parametres.
Researcher Hannah Church says it’s down to the rest periods, and that two minutes is too long.
“In order for people to get the most out of HIIT, which may be the answer to the difficulties of paying for and getting to the gym, we need to get the timing right. Our research showed just how important this is, because we found that 30 second intervals with 120 seconds of rest meant that participants’ heart rates didn’t stay up. 120 seconds is just too long to be resting for.”
So while this is a tiny sample, bear this in mind the next time you want to maximise the benefits of your HIIT session.