Unless you’ve been on the fitness equivalent of Mars for a few years, you will be well aware of High Intensity Interval Training (HIIT). The mix of short bursts of very intense exercise with short rests is a great exercise method for the time poor.
HIIT works – but how and why?
Like many things, ‘high intensity’ is personal to each of us. The fitter you are, the more intense your workout needs to be to get the HIIT benefits.
Fortunately there is a simple gauge. Most of us know that moderate workouts are defined as those where you can still hold a conversation while exercising. If you are doing enough for your workout to be classed as intense, you will be struggling to talk while doing it. Less chat, more calories burned!
When we do moderate exercise, our bodies can provide enough oxygen to keep the muscles supplied. This does not use up too much of the body’s reserves, but still builds endurance and improve the performance of the cardiovascular system.
Working at high intensity means that the body simply cannot provide enough oxygen to the muscles. At this point the muscles start to break down their own energy stores, which are mostly a substance called glycogen. Not only are calories used during the workout, but they are also needed afterwards for healing and also to restock the ‘stores’.
This effect is called the ‘afterburn’ and slightly raises your metabolic rate for some hours after exercising. HIIT really does make a difference.
Government exercise guidelines are that adults should do 75 minutes a week of vigorous activity, and HIIT certainly counts as that. As most exercise classes last an hour, one session a week nearly hits the target. Do two, job done!
It may be hard while you are doing it, but HIIT really does hit the spot.
HIIT is the best thing to happen to the exercise world in years and has made stick to exercise when before I might have given up when I couldn't manage 4-5 aerobic sessions a week, which used to be recommended.