If you are spending more than 30 minutes exercising at the gym you are probably wasting time. Recent research has shown that high intensity interval training (HIIT) is a safe and effective alternative to longer low to moderate level aerobic training and has greater physiological benefits than long, steady state endurance training. In one 30 minute HIIT session incorporates exercises that help build muscle, increase speed and assist weight loss. If you are looking for a way to get more from your workouts or spend less time at the gym and increase fitness maybe HIIT is for you.


What it is:


An HIIT workout involves short bouts of cardio exercises alternating with short, lower intensity bouts of exercise. The difference between HIIT and interval training is in the recovery periods and intensity. Interval training recoveries take the heart rate down close to pre-exercise levels. For example, between intervals exercisers may stop to walk around and get a drink or catch their breath. HIIT incorporates active recovery to keep the heart rate higher than it would be in interval training while allowing enough rest to reach maximal effort in the next cardio block. HIIT also increases the intensity of the cardio exercises and reduces the time of the intervals (30 seconds vs. 60 seconds).


What it looks like:


The basic structure of HIIT is simple: high intensity exercises alternated with lower intensity exercises, a framework that can adapt to individuals' needs. Any type of movement, like running, swimming, cycling, plyometrics, body resistance movements, if done at the right level of intensity. There are various recommendations as to the ratio of exercise blocks, but the recovery should never be shorter than the cardio bout. Some programs suggest 60 seconds on and 60 seconds recovery, others suggest 2 minutes made up of 2-4 different cardio exercises and 1 minute active recovery. HIIT workouts take 25-30 minutes.


How it works:


In relations to interval training HIIT keeps higher heart rate through the workout making a workout of the same length more challenging yet still achievable. More recent research has found that HIIT training provides the same physiological benefits as traditional endurance training including increased oxygen update, boosting oxygen consumption, increasing aerobic capacity and muscle function. Additionally, HIIT results in greater post-exercise metabolism or excess post-exercise oxygen consumption (EPOC) - the body continues burning calories 1.5 – 24 hours after exercise. 


Who can do it:


HIIT is safe for most people including healthy adults and those with coronary heart disease. Exercises vary based on the group because each population is capable of different types of movement and reach high intensity at different paces. While safe for many the high intensity and impact necessary for the benefits of HIIT increase the risk of injury and make it unsuitable for some. If you are training for an endurance event than HIIT is not a suitable replacement for endurance activities, but for most people looking for physiological benefits of exercise HIIT is a time efficient and effective workout.



Where to find it:


HIIT is a versatile workout. You can do it on your own, with a personal trainer or in a group class. If you have never tried this type of workout before or if you don’t think you can reach peak intensity on your own keep an eye out for group classes at your local gym. Several national gym chains have adopted HIIT formats in the last year. Wherever you do HIIT make sure that you always warm up before and stretch after the workout and that you are medically cleared and injury free before starting.