The best way to get really fit is to work really hard – fact. And that’s where high-intensity interval training, or HIIT, can help.
‘With HIIT, you alternate periods of high-intensity training with low-intensity recovery,’ says former Olympic sprinter Craig Pickering, who is now a sports scientist at DNAFit. ‘But the key is that the exercise HAS to be high intensity.’
It’s been around awhile. Sebastian Coe’s father and coach Peter used it as part of the future Olympic champion’s training in the 1970s, while a form of interval training called Tabata (after its founder, Izumi Tabata), was initially used in 1996 by Olympic speedskaters. They did bursts of high-intensity effort on a bike for 20 seconds, followed by 10 seconds rest, for four minutes.
What you use it for depends on your goals, but it’s flexible. ‘It started off on the bike – 20 seconds on followed by 20 seconds off for four minutes,’ says Pickering.
The biggest practical benefit of HIIT is that it’s efficient. If you don’t have 90 minutes to spare you can get greater benefits from working hard for 30 minutes.
‘You can adapt it to any sort of cardio – my track-based work used to be six 60m sprints followed by 30 seconds recovery. Then I’d rest for five minutes and go again. But you can also use it in the gym for weights exercises.’
‘It gives you a whole host of training adaptations,’ says Pickering, which is a fancy way of saying it makes you fitter, faster. ‘The intensity raises your metabolic rate higher for longer – if you’re doing steady-state training your heart rate will return to its baseline quite quickly. HIIT burns far more energy and works your heart much harder, which brings greater cardio benefits.’
‘There’s also greater adaptation at a cellular level,’ adds personal trainer and cycling coach Paul Butler. ‘HIIT helps produce growth hormones, increases fat metabolism and improves blood sugar regulation. It also causes more minor tears in the cells in your muscles.’
Don’t panic. This is supposed to happen and is why recovery is vital – you actually get fitter while you rest, because this is when muscles repair themselves stronger, ready for the next session. That means it’s essential not to overdo it.
‘You shouldn’t do more than two sessions a week, and HITT shouldn’t comprise more than half of your workouts,’ says Pickering. ‘It takes longer to recover from high-intensity sessions and if they’re too close together you’ll be too tired to train properly. Less is more in this case, because you have to attack each session really hard. Then your other training should be low-intensity, steady-state recovery sessions.’
And here’s the proof. Research in Norway on cross-country skiers found that one day of HIIT training followed by two days of low-intensity training improved the athletes’ VO2 max – or maximal oxygen uptake, a key indicator of aerobic fitness.
How Can I Add Weights?
And to show precisely how flexible HIIT training is, you can even combine weights and cardio work to create a fast and furious fat-burning workout. ‘Select three weight exercises and perform three cycles with as little rest as possible,’ says personal trainer Jason Anderson. ‘Then jump onto a piece of cardio and perform three to five minutes of 30 seconds hard followed by 30 seconds recovery.’
You can mix up the exercises so you won’t get bored – but with HIIT, you should be working so hard that you will never have time to get bored.
Advice is for information only and should not replace medical care or recommendations. Please check with your GP before embarking on exercise or nutrition regimes for the first time.