HIIT generally refers to repeated sessions of relatively brief intermittent exercise, often performed with an ‘‘all-out’’ effort or at an intensity close to that which elicits VO2 max (i.e. 90% ).

Depending on the training intensity, a single effort may last from a few seconds to up to several minutes, with multiple efforts separated by up to a few minutes of rest or low-intensity exercise.

In contrast to strength training, in which brief intense efforts are usually performed against a heavy resistance to increase skeletal muscle mass, HIT is normally associated with activities such as cycling, rowing or running and usually nothing that externally loads the body like kettlebells, dumbbells, barbells and calisthenics, it’s just pure intense cardio.

One of the most remarkable findings from recent studies on HIIT was the dramatic improvement that can be seen in exercise performance during tasks that rely mainly on aerobic energy metabolism, despite the very low training volume.

A study by Martin J. Gibala and Sean L. McGee in 2008 found that people performing just 2 weeks of HIIT (2.5 hours total time) compared to 2 weeks of endurance training (10 hours total time) exhibited identical performance adaptations, better aerobic capacity, increased fat oxidative capacity (fat loss), improve mitochondrial density (increase energy production) and much more.

While the mechanism of these adaptations isn’t categorically known, the general belief is that the higher the intensity of the workout, the greater the oxygen debt created. Simply meaning: the harder you work, the faster you breathe at a shorter and smaller volume taking the less oxygen in to your system. This creates an oxygen debt known as EPOC, or exercise post oxygen consumption. The greater this EPOC is the more you will see positive adaptations such as a fitter body that has a better use of energy and clears lactate faster.

For those of us who are time-poor, it is great news as it proposes that the ‘pounding the pavement’ mantra can be replaced by a more effective shorter method.

The traditional long efforts of exercises are almost unsustainable for the modern person, in training facilities all over the world the eradication of long endurance efforts is slowly becoming the norm.

Even though there is a place for some long aerobic efforts, the fact is that the longer we are on our feet, the greater the chance for the body to sustain overuse and overtraining type illnesses and injuries. So most teams and coaches of individual athletes are minimising that type of training and incorporating high-intensity interval training where they get great training effect as well as reducing the risk of injury and illness in a much faster time.

In conclusion you get FITTER, HEALTHIER, LEANER IN A MUCH FASTER TIME FRAME.