In a world where we seem to have an acronym for everything you may have heard of two in particular in the gym or in classes: HITT and LISS. So just what is HIIT and LISS an how to do these two types of cardio differ?
The easiest way to think of the two is the 100m sprint vs the marathon. HIIT stands for High Intensity Interval Training – it is ‘short burst’ exercises such as regularly spaced sprints. The idea of HIIT to do very high intensity exercise for short periods of time, followed by short rest periods, repeated for a number of sets. An example of a HIIT training routine might be 30 seconds sprint at full speed followed by 30 seconds rest (or slow walking)- and repeating this for a total of 20 minutes.
The aim of HIIT is is to raise the heart rate to consistently high levels for the period of the workout causing your body to enter a high fat burning state; due to an effect called ‘Excess Post Exercise Oxygen’ your metabolism remains raised for hours after a HIIT workout, meaning you burn calories for hours after the cardio has finished. Gym classes such as spin cycle classes or Virgin Actives’s grid are examples of a HIIT training, but it can be done with nearly any exercise that gets your heart rate high.
LISS at the other end of the cardio spectrum, stands for Low Intensity Steady State, which can be thought of as your ‘long distance’ style cardio. While HIIT is your high intensity on-off workout, LISS is about exercising at the same pace for longer periods of time. An example would be slow jogging, cycling or cross trainer at a steady speed for 40 minutes. Another example could be certain types of yoga or Pilates if the heart rate is high enough.
So which is best? To make one thing clear, both forms of cardio are good for you! Both increase your aerobic / anaerobic fitness, both reduce body fat while improving blood pressure and general cardiovascular health.
If efficiency is your end goal, HIIT is definitely the answer. By keeping the heart rate very high, HIIT burns calories and body fat at the highest rate per hour (some burn up to 1000 calories per hour) but HIIT can not be maintained for as long as LISS. As with most types of exercise, what works for one person, may not work well for another- so give both a go and see which you prefer to help you reach your training goals.