A study suggests that performing bursts of HIIT (High-Intensity Interval Training) may be more effective when it comes to losing weight compared to longer low-intensity training.
The study, published in the British Journal of Sports Medicine, was analyzing the results from 36 earlier studies. Even though all the subjects lost weight, the ones performing HIIT experienced 28.5% greater weight loss. Some scientists however said that doing HIIT might not be the best weight loss solution for everyone. For some people, it may increase the risk of injury and cause relatively higher cardiovascular stress.
What do the studies say?
Scientists from the Federal University of Goias, Brazil, were analyzing data gathered from 576 male and 522 female participants who had varying fitness levels. Interval training in the context of the study was defined as cardiovascular exercise consisting of repeated short bursts of intense activity, with rest periods interspersed between each burst. Swimming, cycling, boxing, and running were included as activities comprising the study.
This type of training was compared with one consisting of longer continuous moderate-intensity workout sessions, most of which laster between 30-45 minutes. The duration of the study was at least 4 weeks for all participants.
The ones performing interval training lost on average 1.58kg (3.48lb) compared with the 1.13kg (2.49lb) lost by those participants performing lower-to-moderate intensity workouts.
It seems that sprint interval training was especially effective for weight loss, even though scientists remarked that the large variety of training regimes made it hard to recommend any regime in particular. The NHS recommends at least two and a half hours of moderate aerobic activity, like jogging, brisk walking, or cycling, every week.
The results were really impressive
For some researchers, the results seemed counterintuitive since most participants burned more calories while performing longer moderate-intensity training. There might be two explanations for this. Firstly, HIIT might lead to increased energy expenditure after working out, this means that the metabolic rate might be increased for up to 24 hours after a HIIT workout session.
Also, after performing a HIIT session, you may feel less hungry. In the study, it has been shown that hormones in charge of appetite have been affected, which may be the cause for the reduced appetite. However, it’s not easy to conclude if energy intake is decreased as a result of this in the long-term whilst following a HIIT routine, which still makes the underlying reason ambiguous.
One participant said that he was doing 20-second high-intensity workouts on his exercise bike, 3 times a week. He reported an improved insulin sensitivity of 24%. The results were especially impressive with younger people who had low fitness levels.
One of the biggest problems people have with exercising is that they would go on a treadmill for half an hour, burn around 120 calories, and then they would lie on their couch and eat all kinds of junk food, also known as compensatory eating.
It would seem that HIIT tends to suppress the appetite and target the visceral fat in the gut. It’s not the calories you burn during exercise that matter, it’s what you’ll do for the rest of the day.