What is Interval Training?
The concept of this type of training is simple - intersperse short periods of hard exercise with periods of rest.
So a very simple example might be:
Run hard for 30 seconds
Rest for 2 minutes
Repeat 4-8 times
Often this type of training is called HIIT or High Intensity Interval Training, the reason for this title is because the periods of exercise needs to be very challenging.
The body has different energy systems. Long runs and endurance exercise use the aerobic or oxygen system. This also burns carbs and fat and is used for long time periods of lower intensity exercise.
The Glycolytic energy system lasts for up to 2 minutes and is for more intense exercise and is anaerobic.
The Adenosine Triphosphate or ATP energy system is for high intensity, explosive exercise and only lasts for 10-20 seconds and is also anaerobic.
The body uses these energy systems combined, not independently of each other. However, depending on the activity, one will predominate.
So, with high intensity training you should be working hard enough to use the anaerobic energy systems.
What are the benefits of high-intensity training over cardio exercise?Don’t get me wrong, I’m not condoning running. I’m looking at highly effective and beneficial training.
Cardio exercise is typically long and steady - a 20 minute or longer run, or in the gym swapping from running on a treadmill, to sitting on the exercise bike then going on the stepper.
So here are the advantages of keeping things short.
Improved Cardio-Vascular System.
It’s a simple fact that heart and lung capacity increases quickly with interval training, which in turn improves and expands it - the nature of the workouts push your capacity and recovery time. If your heart rate is suddenly raised, you have the capacity to handle it.
More and Continued Fat Burning
Although the aerobic energy system burns carbs and fat, once you stop, the fat burning stops. Also, to burn a beneficial amount of calories, you have to do the exercise for a prolonged amount of time.
Interval training burns more calories over a much shorter time period. Also, the fat burning continues long after the exercise has ended. It can burn up to 9 times more fat!
You can only work at high-intensity for short periods of time. The energy system is then depleted and the body has to create more, and repair itself, which burns fat.
Human Growth Hormone is needed for repairing the body. High intensity interval training causes the release of HGH much more than any other type of exercise.
The stress hormone, Cortisol, is released with exercising for long periods. This in turn raises blood sugar levels and stimulates the production of Insulin, which is responsible for storing glucose. Cortisol also suppresses the immune system and is Catabolic, which is the break down of muscle tissue.
Remember, nothing burns fat like muscle tissue because it’s metabolic. The more muscle you have, the more calories you burn at rest.
An Increase in Mitochondria
The more Mitochondria you have, the greater the fat burning potential. HIIT increases Mitochondria, powerhouses that turn nutrients into energy.
Performing High Intensity Interval Taining
HIIT can be done by people of any level of fitness. As your body adapts and improves, you up the intensity more. The trick is to be working at 8-10 of your RPE scale. The RPE scale is the rate of perceived exertion -
You can can also use 85%-95% of your max heart rate.
You’re looking at 20-60 seconds of exercise depending on your level.
After this wait until your heart rate drops to around 65% or less of your max heart rate. Or, 3-5 of the RPE scale.
Then, go again - hit another set of high intensity exercise.
If you’re a beginner, it’s probably best to develop your base CV conditioning before you do HIIT.
There are lots of variations you can do with HIIT - kettlebells, bodyweight, running/brisk walking, resistance training with weights…
Whether you’re looking to increase muscle mass, improve your CV or loose weight, high intensity training is a great option.