High Intensity Interval Training (HIT) VS Low intensity steady state cardio (LISS)

– Chris Reeves Bsc Dip Pt

What Is High intensity interval training?

High intensity interval training (HITT) involves alternating between intense bouts of exercise and low intensity exercise. Training can involve both working anaerobically and aerobically, training with or without weights. There are many benefits of HIIT that have a positive effect on the body compared to regular cardio that many people perform regularly at the gym. HIIT is quicker and proves to be more effective for fat loss, helps with muscle retention and creates metabolic change

For many years steady state cardio was deemed to be the optimum for fat burning as it was believed that you use more of your fat stores for energy at lower exercise intensity compared to higher intensity’s. An example of this would be walking on a treadmill or riding a bike in the gym whilst talking to a friend, a site that we are all familiar with.

Low Intensity steady state cardio must not be forgotten.

Low intensity steady state cardio (LISS) is not to be forgotten though it has its place, as combining the both can be a very effective way to train. Although HIIT is an excellent fat burner you can’t do it 5-6 days a week as it will eventually have a negative impact. A form of rotation works best so combining both types LISS and HIIT over the week. LISS still has its place for fat loss in moderate amounts form a pure calorie burning point of view, meaning you only burn calories and not changing the way your metabolism works.

With LISS you will only be burning fat for as long as you are exercising and when you stop exercising the fat burning stops. However with HIIT your metabolism speeds up and will continue to burn fat for up to 24 hours after you have finished exercising.

Is HIIT for everyone or just for the super fit?

HIIT has its place not only for a fat loss and fitness but in the rehabilitation world too. A study performed by the American Journal of Cardiology found that interval training provides an effective means to improve the cardiovascular fitness and health status of highly functional patients with coronary artery disease. They also revealed that interval training improves anaerobic tolerance to a greater extent than the traditional exercise training model without increasing the risk to the patient. Supported research by the European Journal of preventive cardiology found that High intensity aerobic interval exercise is superior to moderate exercise for increasing VO2 Peak in stable Coronary Artery Disease patients.


Want to speed up your Metabolism and Burn Fat Faster?

If you want to change your metabolism, you have to increase muscle mass and increase your muscle’s oxidative capacity. Your muscles have energy producing units called ‘mitochondria’ and this is where ATP (the source of energy that keeps everything going) is made and fats are burned.  So in simpler form the more mitochondria you have and the more active they are the greater oxidative capacity you will have for fat loss.

HIIT increases mitochondrial capacity and you in fact increase the amount of mitochondria you produce. Studies show that you get greater fat loss through high intensity training because of the increase in oxidative capacity. Whereas with LISS you’re only burning calories at that precise moment and it has a massive effect to you over time as your body adjusts to it and you end up needing more to lose fat.



Everyone has a personal preference how they enjoy training and what work best for them.  HIIT is quicker, proves to be more effective for fat loss, creates metabolic changes, and helps with muscle retention but not everybody can do HIIT. LISS has its place for fat loss in moderate amounts but as previously mentioned only to burn calories & not make changes to your metabolism and takes twice as long to achieve similar results.