What is HIIT?
High intensity interval training came into vogue in the late 90’s, and has persisted in one guise or another ever since. It seems to have spawned from training protocols used by Japanese short track speed skaters – under the tutelage of a guy named Tabata. As such, his name has been associated with one of the more popular HIIT protocols – the Tabata Method.
The basic theory behind this is that an individual will complete high intensity bursts of activity followed by short periods of total rest. In the Tabata method this means going all out for 20 seconds, then stopping completely for 10 seconds. This is repeated a total of 8 times – meaning the whole HIIT protocol takes only 4 minutes. Now you’re beginning to see why it might be popular.
Other methods extend this protocol for longer periods – things like hill sprints (where you sprint up a hill but jog back down) or The Bear complex (look it up on Google). There’s almost no limit to the number and type of different HIIT protocols available, using pretty much every single type of training conceivable.
Well, the original research by Tabata and his team showed that the 20s on, 10s off approach to exercise was as effective in building cardiovascular improvements as a more moderate, steady state of cardio performed over an hour. His subjects would either do 5 hours of steady state cycling per week, or one hour of steady state cycling and 4 “Tabata” sessions. Whilst the team doing the 5 hours of cycling had greater V02 max (read: fitness) at the end of the programme, the ones doing the Tabata Protocol made the biggest improvement in fitness. They also had significant increases in anaerobic capabilities that were not seen in the steady state training group.
It gets better.
Not only do you have to work out for shorter periods of time to get the same (if not better) results, but you also increase the rate of Excess Post-exercise Oxygen Consumption (EPOC). Wow! In English: any type of exercise causes you to burn calories during the workout. There is also a follow up calorie burn – as your body takes the exercise stimulus and interprets that into improvements in strength, speed, power and fitness. This additional calorie burn is known as the EPOC. Normal cardio has about 7% of calories being burned through this process – that is, if you burned 100 calories during the exercise you’d burn another 7 afterwards through EPOC. HIIT training doubles this – to 14%!
So let’s all go and do some HIIT for fat loss, right?
Wrong! As with everything, there are negatives as well as positives. And numbers need to be examined to make the conclusions. “Double your EPOC” sounds great (to an exercise physiology nerd at least), but what does it mean in the real world? And is HIIT actually a feasible training protocol for us?
EPOC in context
How many calories do you burn in an hour on a seated cycle? Let’s assume you weigh 200lbs, and train at a moderate intensity (note my comments on calorie counting with steady state cardio here). The answer is…..
::Drumroll:: ….. Around 750 (actually it varies with intensity, which varies with fitness, which is why I don’t like calorie counting on exercise).
You get a wonderful EPOC effect from steady state exercise too – 7%. That means you burn another 52.5 calories post workout.
So, steady state for an hour burns around 800 calories in total. HIIT for 4 minutes burns about 80.
But you’re cheating! You can’t compare an hour’s exercise to 4 minutes!
Of course I can. Go and try to do a proper Tabata protocol. See how easy it is to complete (don’t do this if you’re unfit – I don’t want a lawsuit when you keel over and die). HIIT done properly (at a high enough intensity) is awful. It will make your lungs burn and the back of your throat taste like blood. You’ll be coughing for days. Your muscles will burn like there’s no tomorrow. From 4 minutes of exercise.
The simple fact is most people can’t handle tabatas. Even those that can don’t recover properly from them. You can easily complete 5 hours of static cycling per week. You probably won’t even notice you’ve done it (I should know, I used to ride 60 miles to and from work every week). But you absolutely can not do 5 HIIT sessions per week. You just can’t recover in time.
Put it into context
With all the advice given on this site we are seeking to create an environment where training and diet are fixed with as little effort as possible. Why? Because it’s the changes you make for the long term which have the lasting impact. People that go and try HIIT with the mistaken believe it will turn their body into “a fat burning furnace” burn out and quit.
Pick a dietary regime that’s easy to stick to, healthy and enjoyable. Supplement that with adequate barbell training (for the secret of why this works, click here). Then get enough rest. We’re looking for a long term, big picture solution here. Not a “lose fat quick” scheme that will blow up in your face.