Dangers and Risk of HIIT – High Intensity Interval Training
Below are some of the dangers of HIIT – High Intensity Interval Training that I can think of. There may be others too. HIIT is vigorous exercise and all of us – even fit well-trained athletes – can over do it! Please read the points below before you think about taking a HIIT exercise class. I personally think vigorous or HIIT training needs to be done very carefully. Be smart! Don’t rush in and if you are in any doubt, have a medical check or come in for a Chiropractic or spinal check up before you start. Done wrongly HIIT training can do a lot more harm than good.
Obesity, Type 2 Diabetes, Cardiovascular Disease or High Blood Pressure
There are clear risks, which include heart attack, strokes and sudden death. Andrew Marr believes his stroke was due to HIIT training. If you do have any of these conditions you must be very careful. If you’re unsure I would strongly suggest a medical check up first, even if it’s just to rule out any of the above conditions and I personally believe you should not do HIIT at maximum intensity if you are in one of these categories – please keep it safe!
Risk of joint strains.
Many fit sports people add HIIT training into part of their overall training routine; they warm-up, cool-down, prepare carefully and maintain good technique. We don’t always see this, so we may assume we’re safe to go mad too.
Risk of stopping exercise completely through injury
Lack of motivation or confidence, especially if we strain ourselves and make the terrible assumption that ‘all exercise is bad for us’. I must say this is something that really annoys me! It’s not at all! It’s just that you may have strained yourself or that you need to adjust and vary how you exercise.
I’ve done my HIIT training so I can sit all day!
This is a huge mistake. You will probably be fitter if you just get up from your desk regularly, use a sit-stand desk, or use the stairs not the lift, than doing your HIIT training. Please don’t make this misguided conclusion.
Development of long-term tension with repetitive bad habits.
Just watching Michael Moseley horribly hunch his shoulders on the BBC video is a great example (sorry Michael!) He’s probably not aware he’s doing it… until he starts to feel pain! Once again I prefer exercise to be done with good technique and awareness.
Development of over-use injuries if you continue to do too much repetitive high-impact exercise.
I’m a huge fan of variety in exercise (diet, and life in general!). Otherwise, this could lead to stress in the joints and boredom for the body – change what you do and keep your body guessing!
Increased risk of Osteoarthritis
There is an increased risk of Osteoarthritis or joint wear and tear if you continually and excessively strain the joints vigorously – training for a marathon for example. Personally I much prefer the idea of a triathlon with mixed activity – far kinder to your knees over the years! If you have some osteoarthritis then vary your activity so it is comfortable and avoids straining the worn joints – swimming or cycling may be easier for example.
Increased risk of injury among untrained people
Increased risk of injury among untrained people especially if you follow a routine that leaves you feeling “as if you literally can’t do any more” as some trainers like to do. When the body gets tired it loses strength and in turn you will perform exercises with either bad or no technique.
Headaches, Muscle weakness, Nausea or feeling Faint
Risk of headaches, muscle weakness, nausea or feeling faint if you don’t eat well. Be especially careful if your blood sugars are low, or you are on a low calorie diet or fasting, in which case you need to take extra care with your diet and increase your fluid intake.
Risks of over-training
Risks of over-training – colds, viruses, fatigue and injury. It’s essential to take rest days. I do not believe you need to train every day but if you really insist then alternate harder days with easier days. Be extra careful to plan routines so as to avoid repetitive strains that leave you fatigued.
Because HIIT can be punishing to the extreme, it is safer if you’re reasonably fit to begin with (I always used to think I needed to be fit to play squash). Pushing yourself to the limit is not advised if you’re unfit or have underlying health issues. It’s a mistake to think that because they only last a few minutes they are an easy option.
HIIT can be safe and also essential for some sports, but for most people, especially if you’re fit enough, a gentler form of HIIT is better, as indicated by a study from Canada* that showed remarkable health improvements over several weeks. I agree with the idea that it’s ok to feel as if you’ve worked hard, but never to the point you are in extreme pain or discomfort. You need to push yourself a little harder to progress, but only in range of your own ability, and if you’re not sure what this is, seek clear guidance. Always listen to your body and get professional advice before embarking on a new fitness programme.
I was very interested to watch the BBC Horizon program ‘The Truth about Exercise’ with Michael Moseley. It is clear that exercise is very important. It is also clear that we are all different so what works for one doesn’t necessarily work for another, so we need to find an individual exercise programme that works for each of us. There is always a fine line between exercise and strain so please be careful and make sure your exercise is healthy and with long-lasting benefits.