HIIT- fitness fad or is it as awesome as they say?
Updated: Jul 6, 2021
It's quickly become a fast and popular way to get fit. Not only do gym's now offer dedicated HIIT classes but there are even dedicated HIIT fitness studio's. It's High Intensity Interval Training and it all started of as a result of the 1996 study by Dr Izumi Tabata. Dr Tabata had been researching the aerobic (steady, longer lasting) and anaerobic (shorter bursts of activity whereby oxygen isn't used) exercise energy systems for some time. He was interested in a repeat sprint method being used by a Japanese speed (ice) skating coach, so he tried that protocol with a range of 20-30 year old amateur male athletes and compared that with another group of the same demographic who did steady, moderate intensity (aerobic) 1 hour aerobic training sessions. The results over 6 weeks were astounding- greater increases in anaerobic fitness amongst those who did 7-9 x 20 second stationary bike sprints in a 4 minute period than the group who exercised for an hour, what was more remarkable though was the sprint group also had equally good gains in aerobic fitness i.e. cardiovascular endurance, despite exercising for a much shorter period of time. This has lead to development and study of similar protocols, although that might be using the word similar pretty loosely, as both the sprint and recovery components vary widely from 6 seconds to 4 minutes. The boundaries and definition of HIIT have become increasingly broad and vague. Anyway, here are some Pro's & Con's of HIIT I've come to realise: Pro's 1. THE RESULTS FROM MANY HIIT STUDIES HAVE INDEED BEEN AMAZING In addition to the staggering results to both aerobic and anaerobic fitness from the Tabata study, further studies (here is one featuring females and another on males) have shown HIIT to be effective for weight loss. The benefits extend beyond fitness and fat loss too- it's been shown to produce plenty of cellular level changes with wide ranging implications. There is no doubt HIIT works and is here to stay. Studies will continue in the search for a raft of potential areas of benefit. 2. THE TIME EFFECTIVENESS IS HUGELY APPEALING
Of course just about everyone seems to be time poor these days and cite lack of time as a barrier to regular exercise. Naturally the prospect of getting a really effective workout done in a few minutes is going to appeal. People simply love the idea of quick and that's in large part why it's taking off. I'm one of the many who find that a really appealing part of the method. 3. THE EFFECTS ON BLOOD SUGAR LEVELS MAKES IT REALLY USEFUL FOR MANAGING DIABETES Studies (1 & 2) show HIIT positively impacts insulin and blood sugar levels. This is another area where the results have been impressive given the small investment of time. This could of course could be of interest and something to investigate for those looking to manage or prevent diabetes. In fact the 8/12 method study explained further into this article was funded by Diabetes Australia. Naturally medical or professional advice should be sought by diabetics before diving into exercise this intense. 4. THERE IS STRONG EVIDENCE TO SUGGEST HIIT HAS ANTI-AGEING EFFECTS AND PROTECTS FROM AGE RELATED DISEASE. A study out of Minnesota has shown enormous increases in the ability of mitochondria within cells to produce energy as a result of 3 months of HIIT. Mitochondria function diminishes with age and causes fatigue, increased risk of diabetes, excessive ageing of the skin and other possible physical deterioration. Interestingly this study also featured a resistance training group, and a group who did conventional moderate aerobic activity yet neither of those methods resulted in anywhere near the same changes in mitochondria function as HIIT. High-intensity interval training improved age-related decline in muscle mitochondria. It's not the only proof of improvement in age-related decline in mitochondria through HIIT. [As an aside, I noted the senior author of the study Dr Nair said in spite of the lack of mitochondria changes with resistance training: "If people have to pick one exercise, I would recommend high-intensity interval training, but I think it would be more beneficial if they could do 3-4 days of interval training and then a couple days of strength training," Along with what is being learnt about HIIT we are finding out that muscle and strength training also really do matter, particularly around diabetes, bone density, falls prevention, depression, and cognitive function] Con's 1. IT'S HARD TO GO THAT HARD THAT OFTEN The obvious and often spoken about downside is the required intensity and having the capacity to muster up the drive and motivation to go that hard, that often (Tabata study was 5 x week for 6 weeks). If you look at the research there is a correlation between the effectiveness of it and how intense it is. To get the big results you have to go very, very hard. Outside of a clinical setting that is going to be difficult to do regularly, hence why this study was done and named 'High Intensity Interval Training in a Real World' This unsurprisingly showed HIIT was lower in adherence compared to lower intensity exercise. Another study from New Zealand also pointed toward difficulty in in long term adherence to HIIT outside of direct supervision. I know from experience the feeling of dread and doubt about whether I can push through the pain when faced with the prospect of repeated massive efforts on the bike when doing my programmed Tabata HIIT session, I can only imagine how daunting that would be for a newcomer to exercise. Sydney University have tried to get this issue that by putting together a method which involves going hard for 8 seconds hard, and following that by going easy for 12 seconds. It certainly is easier, primarily due to lower levels of muscle fatiguing lactic acid, and has yielded some good results. This method isn't a super quick workout though as it's still 20 minutes long. 2. THE TIME EFFECTIVENESS IS OFTEN EXAGGERATED AND MISLEADING. One of the more studied and effective methods is the Wingate test (a long standing means of measuring anaerobic fitness which has been also adopted as an HIIT training method) which involves 4-6 maximum 30 second efforts with 4 minutes rest between each effort. Even in the studies they mention it amounting to only 3-4 minutes of exercise and that is a common way HIIT is explained from a time perspective- only the high exertion time is counted. However, once you factor in the warm up, recovery between each effort and the cool down you are looking at 25-30 minutes. This clip from ABC TV (Aust) also calls it 'getting fit in 6 minutes' but further into the program it's revealed the workouts used actually take 20 minutes. Similarly the original Tabata protocol involves a 5 minute warm up and 2 min cool down creating a total workout time of 11 minutes, plus in practice if you go as hard as the protocol demands you'll find it'll take you many minutes before you can simply resume daily activity! 3. IT'S BEEN EXPANDED TO INCLUDE EXERCISES WHICH DON'T MEET THE CRITERIA People are doing resistance training and body weight exercises as part of, or indeed all of, a so called HIIT program, however none of the studies feature resistance training, it is all cardiovascular activities such as cycling or running. There are plenty of popular You Tube fitness gurus who demonstrate HIIT routines that aren't actually high intensity, doing a plank or push ups or some ab crunches won't get you to the required level of cardiovascular intensity to get the benefits. While it may well be an effective way to exercise and indeed feel difficult, those who use such exercises are really doing time-structured circuit training not HIIT and thus not getting the specific, significant benefits. Don't be fooled! 4. IT'S NOT AS PRACTICAL AND VERSATILE AS MANY WOULD HAVE YOU BELIEVE To do it well you are probably restricted to a handful of options such as a stationary bike, a rowing machine and outside on an oval with an accurate timer. You need to be able to monitor the time and control the resistance/intensity or speed closely. That is very hard to do on a treadmill. As mentioned, for most people most calisthenics and body weight movements aren't going to be demanding enough from a cardiovascular perspective. It's not as adaptable as you may have thought. Professional advice While there's no doubting the remarkable effectiveness of HIIT when done properly, I'd suggest it isn't the best option for someone trying to establish an exercise routine. Extreme pain and discomfort aren't particularly inviting to somebody who's trying to develop a good relationship to exercise. In my 25 years as a personal trainer I've learnt that building habit and consistency will always trump intensity, let your mind and body get in the groove with exercise over months of regular moderate effort. Keep both overwhelm and soreness to a minimum. 3-6 months of consistent exercising would be a good platform from which to launch into HIIT. Even having preparing your body for it over time I'd still suggest a couple of HIIT sessions a week would be plenty, combine it in your exercise week with some conventional longer, steady cardio workouts and some resistance training and I think you'll find all 3 types of exercise compliment one another nicely, both physically and psychologically. Besides which, although as outlined earlier HIIT has been shown to be effective for weight loss, a more recent study suggests that the old style endurance training is still better for shedding the pounds. As for which of the growing number of HIIT methodologies to choose Tabata is quick and easy to understand if you are willing to go very, very hard. Plus you can get timed tracks with motivational music to play on your phone. Alternatively the 8 sec sprint, 12 second recovery method is an easier entry to this type of training with the trade off being you'll be investing more time i.e. 20 minutes. Be real about it- HIIT is bloody hard work, while everyone wants results enjoyment and sustainability matter, and they inevitably lead to lasting results. Look upon HIIT as a tool but not the whole tool kit. Want to cut through the confusion and get fit in an intelligent and effective way? Drop me a line or have a look at what I offer with exercise programs.