HIIT (High intensity interval training) is where you do short bursts of explosive, challenging exercises with minimal rest in between, aiming to keep your heart rate at a high level. The theory behind HIIT training is that the fluctuation of heart rate enables you to burn more calories per hour than doing steady state exercise alone (running for an hour for example). 

Hiit circuits often contain plyometric or explosive exercises which work the white, fast twitch muscle fibres of the body, enabling growth and muscle fatigue. This combined with an elevated heart rate result in a high calories burn during the hours exercise. 

There are many different ways to construct a HIIT workout regime, tweaking the different parameters as your fitness improves. These parameters include exercise duration, exercise speed, rest time, or the inclusion of a weight or some form of resistance. 

Here is an example of a beginners HIIT circuit, equipment free:

30s x

– Squat jumps

– Burpees

– High knees

– Mountain climbers

– Star jumps

Do this circuit 4 times to begin with, have as little rest in between exercises and you can and rest at the end of the circuit.

HIIT training should always been included in your weekly workout in order to improve fitness as quickly as possible, burn the most calories you can in a given time frame and in order to continue burning a higher level of calories for 24 hours post workout.