This type of training is designed to improve overall performance in short sessions anywhere between 3 minutes and 30 minutes. It is extremely effective and has been found in many studies to produce much much better results than steady or endurance training (e.g 45 minutes on a treadmill at a constant speed).

Some studies have even found that the amount of energy burned in HIIT is up to twenty times more than that burned in steady exercise for the same amount of time, it's also been shown to produce up to five times more muscular improvement than endurance training.

This isn't saying that it's the solution to all, but i cannot stress enough how effective it is as a form of CV.


What is it?

If we use running on a treadmill as an example. It would begin with a warm up say 5 minutes at a slow jog. Followed by timed bursts of high intensity exercise (say 30 seconds sprint) these bursts might be repeated 6-8 times. Inbetween the bursts medium intensity exercise continues (around half maximum running pace). After the last sprint burst, a warm down period of 3-5 minutes at a slow jog. Then the session is over.


Here are some example HIIT workouts depending on your ability:


Warm Up: 5 Minutes Jog

Sprint Duration: 30 Seconds (high intensity)

Rest Duration: 90 seconds (medium intensity)

Repetitions: 6

Warm Down: 3 Minutes Jog


Warm Up: 5 Minutes Jog

Sprint Duration: 30 Seconds (high intensity)

Rest Duration: 60 seconds (medium intensity)

Repetitions: 8

Warm Down: 3 Minutes Jog


Warm Up: 5 Minutes Jog

Sprint Duration: 30 Seconds (high intensity)

Rest Duration: 30 seconds (medium intensity)

Repetitions: 10

Warm Down: 3 Minutes Jog

You can vary the repetitions, sprint duration and rest duration depending on your ability and how you feel HIIT works for you after your first session. These small sessions 3-4 times a week will make a huge difference to your body as the weeks pass.

Remember, this doesn't just have to be running. You can apply it to any sort of exercise, rowing, swimming, biking (this is what spinning classes do), weight lifting, body weight exercises etc! It's the intervals that are effective not just the type of exercise.

How does it work?

When you train in a steady state (running at the same pace for a long time etc) your body becomes used to the stress it's being put under and learns to conserve energy as you run. This means that you burn few calories and recover quickly.

Due to the constant changes in speed and heart rate during HIIT, your body cannot adapt and thus causes you to use a lot of energy in order to achieve the speeds and keep enough oxygen going to your muscles. It also means that after exercise you continue to burn calories, this is due to EPOC (excess post-exercise oxygen consumption).

EPOC basically means that in recovery after intense exercise your body needs to use fuel in order to go back to its rest state (e.g replenshing fuel stores, balancing out hormones, repairing damaged cells). It causes your body to continue using energy even when you've stopped exercising. Some studies have found that it takes over 24 hours for your body to recover fully from a HIIT session. Hence it being so effective at fat loss as well as cardiovascular and respiratory improvements.