Want to lose weight? HIIT it hard, say researchers
New study finds that shorter, more intense, training is better for weight loss – but there is no silver bullet
It’s official: you don’t have to exercise for hours or run marathons to lose weight.
Instead, a major study shows “sprint interval training” seems to be more effective for dropping kilos than doing longer workouts at a moderate intensity.
The results, published in the British Journal of Sports Medicine this week, are good news for people who struggle to find time for the recommended one hour a day of exercise to drop kilos.
The weight-loss benefit of high-intensity interval training (HIIT) is well-known, but this is the first review of 41 studies from than 1,000 participants on this.
The analysis proves what sports scientists and personal trainers know in practice on the field or in the gym.
Lead author Dr Ricardo Borges Viana, of Federal University of Goias in Brazil, said: “Interval training describes the intermittent intense effort, interspersed with recovery periods.”
The two most common types of HIIT are sprints – running, jogging, speedwalking and cycling – and various other exercises.
Justin Durandt, manager of the Discovery High-Performance Centre at the Sports Science Institute of South Africa, noted that 10 minutes of explosive exercise could reap the same rewards as 40 to 60 minutes of more moderate training.
He said recently: “HIIT is a great way of training in that you get your most bang for your buck timewise – but it is not for everybody.”
Sports scientist Marc Booysen, from the Centre for Exercise Science and Sports Medicine at the University of the Witwatersrand, said HIIT seemed to burn more fat for 24 hours afterwards.
“Most people exercise around 70-75% of their maximal heart rate, whereas in HIIT the intensity of your work periods should be a lot higher,” he noted.
A Canadian study among men found one minute of very intense exercise produced gains similar to less vigorous training, lasting five times longer.
In the new review both interval training and a continuous workout reduced overall weight and percentage body fat (the percentage of fat that makes up body weight), irrespective of starting weight or gender, the researchers found.
Interval training proved nearly a third more effective (28.5%) in the amount of weight loss, though there wasn’t much difference in the percentage of body fat shed.
“Factors such as supervision; age under 30; walking, running and jogging; study quality; and studies lasting more than 12 weeks all influenced weight loss in the interval training programmes,” they stated.
They also warned that higher-intensity training could “increase the risk of injury and impose higher cardiovascular stress … and result in higher discomfort”.
They also examined such a wide range of different training programmes that they could not recommend one specific type of training over another as the magic bullet.