Mark Wood of British Military Fitness explains the benefits of HIIT and details the workouts that work

High intensity interval training or HIIT involves working extremely hard for an astonishingly short period of time, and in the end bringing remarkably similar results to much more prolonged endurance training, such as steady efforts. Although it’s a training routine that’s been around for a while, with the likes of Sebb Coe in the 1970s and long-distance great of the 1920s  Paavo Nurmi both having practised it, over the last few years it’s seen a boom in popularity – perhaps thanks to food bloggers such as The Body Coach advocating it on social media.

The benefits of HIIT

When using HIIT as an exercise protocol there’s a greater use of lipids as a fuel source.

Due to exercise intensity there’s a significant increase in the release of growth hormone. This hormone will have huge impacts on changing body composition such as helping to remove excess body fat and building/maintaining lean muscle.

HIIT has been shown to improve insulin sensitivity and glucose metabolism. This is very beneficial for those who suffer with poor blood glucose profiles, such as diabetics or the overweight (although it must of course be used with care, and be reflexive of fitness levels).

HIIT produces an extended EPOC (“excess post oxygen consumption”) period – more commonly known as the “after burn”. This is very significant in the hour or so following the session but can last for up to 48 hours. During these two EPOC periods the metabolism is working overtime as the body’s numerous systems that were “sparked” return to a more steady-state. Hundreds of calories can be consumed during EPOC.

HIIT can increase maximum oxygen uptake (VO2max), lactate threshold, lactate tolerance, power and performance economy.

HIIT’s mental toughening aspects should not be neglected either – the fortitude required to complete, for example, a Tabata workout

4 recommended HIIT workouts

Medium intensity (cycle/run)
Cycle or run for 20 seconds at 75 percent effort, then walk/pedal for 40 seconds (or until heart rate has come down to about 60-65%% of heart rate max. Repeat 3-6 times.

High intensity dynamic (circuit)
Complete the following exercises as fast as you can and take 30 seconds between each. Repeat 3-5 times depending on your fitness. Remember to maintain good form throughout the circuit. Your heart rate should be over 80 percent very soon after commencing, and remain around that figure thereafter:

  • 20 press-ups
  • 20 squat thrusts
  • 20 squat jumps
  • 20 burpees
  • 20 star jumps
  • 4 x 40m sprints (walk back recovery)

High intensity (running)
30-second hill/treadmill sprints on slight incline; 45-second walk recovery. Repeat 6-10 times Your heart rate should be over 85 percent very soon into the workout and touching 95% at times.

Very high intensity (cycling)
20-second flat out on exercise cycle; 10-second recovery x 8. This is the original Tabata protocol. Your heart rate will be over 90 percent very quickly, will reach maximum, and remain at/very near maximum for much of this 4-minute session.

Always warm-up and cool-down.