HIIT - what is this?

HIIT - I've seen this in posts alot, but I am not sure what that means.

high intensity interval training. for example running at 40% effort for 2 min then 85% for one minute then back to 40% and so on...intervals of very high effort. if you google it you'll find more

Definition:

High-intensity interval training (HIIT) or sprint interval training is an exercise strategy that is intended to improve performance with short training sessions.

A HIIT session involves a warmup period, several short, maximum-intensity efforts separated by moderate recovery intervals, and a cooldown period. The period of alternating effort and recovery intervals typically lasts a total of 15 minutes.

Studies by Tabata[1], Tremblay[2] and others have shown this method to be more effective at burning fat and maintaining, or building, muscle mass than high-volume, lower intensity aerobic work-outs. A study by Gibala et al[3] demonstrated 2.5 hours of sprint interval training produced similar biochemical muscle changes to 10.5 hours of endurance training and similar endurance performance benefits. According to a study by King [4] , HIIT increases the resting metabolic rate (RMR) for the following 24 hours due to excess post-exercise oxygen consumption, and may improve maximal oxygen consumption (VO2 max) more effectively than doing only traditional, long aerobic workouts.[5][6][7][8] Long aerobic workouts have been promoted as the best method to reduce fat, as fatty acid utilization usually occurs after at least 30 minutes of training. HIIT is somewhat counter intuitive in this regard, but has nonetheless been shown to burn fat more effectively. There may be a number of factors that contribute to this, including an increase in RMR, and possibly other physiological effects.

Ok laymans version short bursts (or sprints) during your cardio workout to achieve better results....btw I do HIIT trining all the time its really great.

Very cool - thank you!  I guess I already do that with biking - so that is great!