The myth of HIIT training - Fitlife

The myth of HIIT training

You have probably heard a lot about HIIT training over recent years. It has become the thing to post on social media and to be seen doing in the gym thanks to the likes of the body coach and other social media fitness bloggers. But, what really is HIIT and why are we doing it?!

HIIT is an acronym for High Intensity Interval Training, which refers to short periods of intense exercise followed by a period of rest/recovery repeated multiple times. The reason we do this is to spike out heart rate during the high intensity period to force our body to work hard to recover during the rest period. When we repeat this multiple times we create an oxygen deficit in the body, which means that when our HIIT workout has finished, our body has to continue to use energy to replace the oxygen in the body, resulting in calories burning long after your workout has finished….WOOP WOOP!

Now, here is the tricky part.. Getting it right. Since being a PT I have seen a lot of confusion between HIIT training and circuit training. Here is an example of what I mean…


20 seconds burpee box jumps / 40 second recovery

20 seconds assualt bike / 40 seconds recovery

20 seconds thrusters / 40 seconds recovery

5 rounds



50 seconds squats / 10 second recovery

50 seconds press ups / 10 second recovery

50 seconds sit ups / 10 seconds recovery

5 rounds


You may look at this and see the circuit session as being the most demanding because of the time per exercise, which for some may be true, but the quest for an oxygen deficit created by high intensity work is unrealistic when being asked to work for 50 seconds at a time. Imagine trying to sprint completely flat out for 50 seconds with 10 seconds rest 15 times… By the 3rd one you will be jogging, or crawling! This means the intensity has been lost and the stimulus of ‘high intensity’ has been lost. For a HIIT session to be effective every single high intensity period needs to be a sprint at maximum effort and to do that you simply have to take enough rest between each period. Also, notice the exercises that the HIIT session has as apposed to the circuit session.. Each HIIT exercise is a full body movement where as the circuit movements are focused on one body part.. Which of these will burn the most calories? The full body move 10 times over.


So, next time you want to get the maximum out of your HIIT session and to be sure to trigger fat loss by creating an oxygen deficit, make sure the high intensity period is exactly that – HIGH INTENSITY, and then make sure the recovery period is adequate for you to go hard in every single one.


Enjoy getting lean for summer.


Char x