So you’ve heard about this new thing at work or in the gym called HIIT, did a google search to learn a little more and found out it’s amazing, everyone is doing it and so should you. You know how to do it, and your ready to hit (hiit?) the track. But hold on a second, what will it actually do to you?

There are 4 main physiological effects that you may be interested to know before starting HIIT.

Increase RMR:

The whole idea of HIIT is not to burn fat while you are working out, but rather in the 24 hours afterwards. The body does this through a metabolic spike - an increase in your RMR (Resting Metabolic Rate). After a successful HIIT session your body will metabolize fat faster for a longer period of time than steady state training (LISS).

Increase Lean Muscle Mass:

The right type of HIIT will increase your lean muscle mass. This is particularly interesting for body builders transitioning from a bulk to a cut. HIIT provides a way for the body to burn fat whilst retaining muscle. LISS will activate a hormone called Cortisol which breaks down muscle tissue - effectively making your body eat its muscles.

Improved VO2 Max:

VO2 max is the maximum capacity to transport and use oxygen during incremental exercise. Also commonly known as maximal oxygen consumption or maximal oxygen uptake. HIIT increases your VO2 max, making it easier for you to get utilize the oxygen you breathe in. Basically, HIIT makes you fitter!

Higher Lactic Acid Threshold:

Whatever your view of lactic acid, friend or foe (see NYT article) the truth is it hurts, so being able to go longer and harder without lactic acid in the muscles has got to be a great thing right? Right. HIIT will increase your lactic acid threshold which enables improved athletic performance.