Intervals and Threshold Training - what, how and why

Interval Training – how to burn fat for free!

Intervals are without doubt the most effective cardiovascular training system to increase your fitness and lose fat. Unlike the fat burning zone it uses very few calories from fat but it does burn a large amount of calories and more importantly it increases your metabolism so after your workout you will continue to burn more calories than normal with a good percentage of those coming from your fat deposits, particularly if you eat healthily.


During interval training you want to get you heart rate above 90% for short periods of time. A typical session involves approx 20minutes of alternating between short intense burst of exercise of around 30seconds up to around 3 minutes with approximately the same amount of recovery. The recovery should be done at a VERY EASY level as the aim is to recover so you can go hard for the next effort.
Ideally each effort should be the same or harder than the last effort and you should see you heart rate reach a little higher after each one. The last one should feel almost impossible, but you manage to finish it. A good way to do these is to use distance and time as a measure so you can compare efforts. For example run a set distance and record the time it took you to run it. Next interval try and run it the same time or faster. As the weeks go by try and either decrease the time or increase the distance or even decrease the rest in between intervals. There are many way to perform interval training but the most important factor is intensity. Make sure your heart rate reaches above 85-90% for each interval and you’ll know you’ve had an effective workout.

Threshold zone
This zone is probably the least effective in terms of fat loss and increasing overall fitness but is extremely important when it comes to training for a particular race. It is around 80-90% of your hr max and is often described as the maximum intensity you can maintain for around one hours exercise. This is typically the zone at which a lot of people in the gym spend most of their time at, exercising for around 20-30 minutes. Unfortunately this has the least effect on fitness levels and fat loss compared with intervals and training in the fat zone. It is however very good training for running races from 10km up to a half marathon so if that is your goal then one session a week spent at threshold for 45-60 minutes is a good session to do.

Which zone is for me?
If you are like most people and want to lose fat and increase fitness then begin with 2-3 session per week in the fat burning zone, starting off with 15-20 minutes and gradually increasing until you can do 45 minutes comfortably. Once you reach this stage you should switch to doing 2 interval sessions per week and one fat burning session. Try and increase the duration of the fat burning session as long as possible – a long walk around the heath or a long bike ride is ideal. For variety try a tempo session once every 2-3 weeks. Perform a set distance that will take you apporx 45-60 minutes to copmplete,measure your time and watch your times come down.