Before I get into this, let me just make one thing clear – HIIT is not a bad thing! And there are a lot of places doing it extremely well – Core Collective in London for one. This blog is not written to attack the class as a whole and it is certainly not to persuade you not to do it! It is written with the aim of helping you approach HIIT with the right mentality, using it if it right for you and enabling you to identify the kind of HIIT classes that I do have a problem with.
More Harm Than Good?
High Intensity Interval Training (“HIIT”) involves repetitions of short bursts of intense, maximal effort exercise; usually for anywhere between 20 to 40 seconds. It can be an incredibly effective tool for increasing cardiovascular fitness, sculpting your physique and increasing metabolic rate. It is also incredibly taxing on your nervous system, joints and muscles; especially if you are overweight and unfit.
HIIT is very popular in London at the moment, with new HIIT classes popping up all over the place. People have become accustomed to turning up to a class with loud music and dark lighting – just like a night club – and leaving in the same state: barely able to walk!
My issue with HIIT is that there’s often no focus on form or technique, and it’s now prescribed as the go-to form of exercise for everyone. People have come to expect being “destroyed” after a class or their own personal workouts. There is often no emphasis on flexibility, mobility or activation; all are incredibly important in keeping the body fit and healthy as you age. I regularly see people “smashing” multiple HIIT classes a day, 5-6 days per week. HIIT should not be done more than three times per week (at most), because it is so strenuous. This approach to exercise is completely unsustainable.
HIIT’s rise in popularity is a symptom of what is wrong with the fitness industry as a whole; there’s no focus on the fundamentals and there’s serious “one size fits all” mentality. Having trained 100s of clients in my 5 years as a personal trainer, the biggest issues most people have are a lack of flexibility, mobility and core strength on top of muscle activation issues. All of the above lead can lead to chronic injuries and are further exacerbated by HIIT.
It’s Not For Everyone
Office workers are particularly at risk from HIIT, sitting at a desk for 8 hours a day can cause all sorts of joint and muscle issues. To then go and put so much strain on your muscles and joints is bound to do more harm than good. Furthermore, 40 minutes of intense activity does not cancel out 8-10 hours of sitting down on a daily basis.
What will make a difference to your fitness is incorporating movement throughout the day. You could easily set an hourly reminder to spend 5 minutes moving and stretching if you’ve been sitting for a while, choose (or maybe accept!) to stand on your commute, take the stairs and avoid the lift or escalator. Another way to build movement into your routine is to take your trainers to work and get off 1 or 2 stops early to walk or run the rest of the way home.
Train Like an Athlete
My belief is that everyone should try and train like athletes do. I don’t mean the same training frequency and intensity as athletes, I mean the mentality and the approach. Having trained as a competitive sprinter for 4 years I learned to take every aspect of my life into account: sleep, rest days, nutrition and weaknesses. I learnt to listen to my body. Some days I would wake up feeling tired and fatigued, on those days I wouldn’t train hard, I would do something less intense and focus on recovery.
Most people do HIIT in the belief that it burns more calories, thereby increasing weight loss. It may burn more calories than other forms of exercise, but having calories burnt as the sole purpose of your training is fundamentally flawed and is the contributing factor to injury, imbalance and lack of communication between your mind and body. This approach will eventually lead to overtraining, which is a big problem; it can ruin your immune system, cause insomnia, affect your appetite and release cortisol, which in turn can make you more likely to put on fat.
HIIT Can Be Incredibly Effective
I’m not saying that HIIT isn’t an effective form of exercise, because it really is. BUT it’s important to understand who should/shouldn’t be doing it and note that everyone is different. What benefits one person doesn’t necessarily benefit the next.
If you are looking to get back into exercise for the first time in a while, it would be a lot more beneficial to start with some low impact cardiovascular exercises like walking, cycling or rowing, incorporating daily flexibility and mobility practices (see above videos). After a month or two you could try incorporating HIIT into your routine once or twice per week.