An introduction to HIIT

In spite of the strong medical evidence for the positive role of exercise in preventing and reversing obesity, diabetes, hypertension, dyslipidemia, heart diseases and stroke, not many are able to incorporate regular exercise into their busy lifestyles.

Due to time constraints and workplace issues, interval training might be the answer for the younger generation. Interval training is a type of exercise training, which involves periods of intense exercise and recovery. High Intensity Interval Training (HIIT) is a type of interval training that has been investigated a lot in the recent past and has shown promise both in heart disease prevention as well as in cardiac rehabilitation programs.

HIIT involves short bouts of high intensity exercises, with recovery periods that involve mild intensity exercises. There are different types of HIIT regimes, but the basic algorithm is to have a good warm up, short bouts of the combination of high and low intensity exercises for a time period and cool down.

Sample HIIT regime

5-minute warm up + [(4-minute high intensity exercise& 1-minute low intensity exercise) x 4 times = 20 minutes HIIT] + 5-minute cool down

This is different from Moderate Intensity Continuous Training (MICT) which has been followed for a very long time with well established evidence, in the following ways:

  • HIIT duration is relatively shorter than MICT (20 minutes vs 30 minutes)
  • Calorie expenditure is higher in HIIT than MICT
  • HIIT aids in weight loss and increasing muscle mass at a faster rate than MICT
  • HIIT is applicable for both aerobic training as well as resistance training

However, prior to enrolling in a HIIT program, there are some things to be considered:

  • An individual should be following at-least a mild to moderate intensity exercise regime for 2 months before starting HIIT, so it’s not for those of you who are beginners to exercise
  • It is advisable to have a fitness instructor or a physiotherapist initiate the HIIT and monitor you in the early stages
  • If you are a healthcare professional, remember to assess the physical activity level and exercise capacity of your client prior to initiating HIIT

Every exercise regime has some limitations, some of the disadvantages in HIIT are:

  • It is not advisable for high risk individuals (uncontrolled hypertension, angina, arrhythmias, valve stenosis, pulmonary complications, recent heart attack, exercise intolerance) and senior citizens
  • Chances for injury are higher in HIIT if adequate warm up and cool down aren’t done
  • The recovery period for a HIIT program is comparatively longer than other training, which might affect one’s adherence

With this introduction to HIIT, my aim as a cardiac physiotherapist is to help each and every one of you out there find the exercise regimen that best suits your health, work and lifestyle requirements. The secret to success is being regular with your exercise over continuing periods of time and enjoying every bit of it!