High Intensity Intervals Have The Power To Get You Fit And Fast But Are You Doing It Right?

London fitness studio New Motion has launched HIIT vs House, using the beat to drive fitness and strength gains – instructor Ali Fitz-Desorgher tells RSNG why you need to get into HIIT, and debunks the top myths about it that you’ll see on social media…

RSNG What are the new rules of HIIT in terms of intensity and getting the volume right? ALI FITZ-DESORGHER ‘The great thing about HIIT is that workouts can be as short as five minutes and still be effective, if performed at maximum, or near maximum, effort during the working intervals – you have to feel like you've really earned those rest intervals! Because HIIT is so effective, even if you're performing many different exercises and targeting different muscle groups, as we do in my HIIT vs HOUSE classes, you can still get a full-body workout in well under an hour.’

RSNG Why does working out with music and in a group help to deliver the right intensity? AFD ‘Just like when you're dancing, if the music is on point, you don’t want to stop! The music makes you want to move and jump, even when the sweat is dripping off your nose. And workouts are always better when you're doing it as team. The perfect combination of camaraderie and competition helps you push harder than you thought you could; knowing you're all in it together, but still kinda wanting to finish top of the class.’

Although HIIT is perfect for improving fitness, using power moves promotes strength and muscle’

RSNG What are the top three myths of how to do HIIT that you see people circulating on social media? AFD 1. “HIIT IS ALL YOU NEED” ‘Nope! Your body is highly adaptive and although HIIT is great, if it’s the only training you do, your body will adapt, your fitness gains will plateau, and most importantly, you'll get bored.’

2. “HIIT IS ALL ABOUT CARDIO” ‘Piffle! Although HIIT is perfect for improving your cardiovascular performance, applying resistance and using big, power moves will promote strength gains and improve your muscle tone too.’

3. “SHORTER RECOVERY INTERVALS ARE BETTER”… ‘Codswallop! If you're working at 90% of your max heart rate, for 8 x 30 second rounds, you're gonna need more than a five nanosecond break each time to restock your muscle cells with fuel for the next round. If you start cutting down your recovery time, your effort will tail off after the first round, so you might as well be doing regular, steady-state cardio. A 2:1 or even 1:1 work-to-recovery ratio is fine.’

HIIT uses all three energy systems so you work at max effort for a comprehensive training effect

RSNG What are the benefits of HIIT when you do it right? AFD ‘To move your muscles, your body has to produce a chemical called ATP. You can do this in three distinct ways; the aerobic system (using glycogen and oxygen), the anaerobic glycolysis system (using glycogen but no oxygen), and the phosphagen system (which is like an emergency ration – but only for short bursts).’

‘Each energy system is activated at different work-intensities, so by working at max-effort, you use all three; achieving the most comprehensive training effect on your body.’

RSNG Got any tips to pace HIIT properly so that you can work as hard on the last interval as the first? AFD ‘You can't! You may be able to try as hard at the beginning as the end, but if you're working hard enough, you will fatigue. But to pace yourself correctly, give yourself a mental scale of 0-10 (we call this the Rate of Perceived Exertion, or RPE scale). A 10 should feel like you're running for your life, and a 0 should feel like you're chilling on the sofa watching Love Island. During your work intervals, you should be at a 9 or 10, and during your recovery intervals, a 2 or 3. Combine that scale with the minimum of 2:1 work-time-to-recovery-time ratio, and BINGO!’

RSNG What about heart rate? Do you monitor that? AFD ‘If you have a heart rate monitor it's a perfect way to check that you're hitting 90-100% of your max heart rate. But if you haven’t got one, use the RPE scale instead. If you don't like clock-watching, you can check your heart rate for the first couple of rounds so you know what 90% max heart rate feels like, and then use that to check where you really are on your personal RPE scale.’

RSNG What has HIIT done for you in terms of your own fitness/ body goals? AFD ‘As someone who quickly gets bored on a treadmill or indoor bike, HIIT has helped me squeeze more cardio training into my otherwise overly strength-centric workout habits. I'm also a terrible dancer, so HIIT gives me an opportunity to move to music, without embarrassing myself on a dancefloor.’

RSNG Will it push up my lactate threshold and why should I care about that? AFD ‘Sure will! Your lactate threshold is all about that second energy system I mentioned before (the Anaerobic Glycogen system). When you can't get enough oxygen into your system, your body produces ATP without oxygen, but this has a side effect of creating lactate.’

‘Your body will constantly work to remove the lactate but when you're working super hard, you'll reach the point where you're producing lactate quicker than your body can remove it. That's your lactate threshold. Lactic acid will then accumulate in your muscles, leading to a burning sensation, and eventually you'll be unable to continue. The fitter you are, the higher your lactate threshold will become, and that will allow you to go harder, better, faster, stronger in everything you do.’

BDNF protects our brain and acts as a reset switch giving a strong sense of clarity post-workout

RSNG Can HIIT ever be fun or is it just torture? AFD ‘HIIT is always fun when you have the right moves, the right music, and an awesome team to share the experience with. If you don't enjoy it, you're going to the wrong class!’

RSNG How does the science explain how you feel good afterwards? AFD ‘When you work hard, your brain recognises it as stress, and thinks you are either fighting an enemy or fleeing from it. To protect your brain from stress, you release a protein called Brain-Derived Neurotrophic Factor. This BDNF protects our brain and acts as a reset switch. That’s why we have such a strong sense of clarity after a workout, and our worries seem easily overcome.’

‘Another chemical is released too: endorphins. These minimise the discomfort of exercise, block the feeling of pain and are even associated with a feeling of euphoria. Add to that the adrenaline you’ll have pulsing through your veins, and you’ve got a pretty potent cocktail of naturally occurring feel-good drugs keeping you on cloud nine for hours.’

RSNG Got any other tips? AFD ‘HIIT sessions, like HIIT vs HOUSE, should be fun, sociable, but also challenging. If you’ve never done a HIIT class before, or you haven’t exercised for a while, you can still take part, but always listen to your body and don’t feel peer-pressured into pushing beyond your limits. A good instructor will always offer a range of regressions to make sure there’s an option to suit the less experienced – never feel embarrassed to simplify a move – you’re still working harder than the person on the sofa watching Love Island!’

WHAT NEXT? Try this simple Tabata HIIT protocol that doesn’t require a gym, just a bit of clear space away from roads:

Step 1: Do a 10-minute warm up including bodyweight squats and walking lunges, as well as a 5-minute jog.

Step 2: Sprint for 20 seconds and rest for 10-20 seconds. Repeat this eight times and aim to try as hard in the first interval as the second.

Step 3: Warm down and stretch.

Follow Ali on Instagram @ali.fitz.fitness and visit New Motion for more on HIIT vs HOUSE

*Comments are for information only and should not replace medical care or recommendations. Please check with your Doctor before embarking on exercise or nutrition regimes for the first time and make sure you have a good basic level of fitness before attempting a HIIT session.

Follow the writer @the_adventure_fella