HIIT [High‐intensity Intermittent Training] from a Common Sense Viewpoint

HIIT [High‐intensity Intermittent Training] from a Common Sense Viewpoint. Throughout humankind’s development, short‐duration, high‐intensity exercise has been a prerequisite for both survival and human progression. In primal times, humans, for the most part, would not have moved long distances by running slowly or “jogging” as our modern world likes to call it; rather, they would have walked because, from an energy perspective, it is the most efficient form of gait. In comparison, humans running at high speeds are energetically inefficient. Having said that, throughout a day, short, vigorous bouts of activity would be required for hunting, gathering, carrying, digging and escaping danger. One can easily imagine that jogging through fields and forests would not be a particularly effective hunting strategy.

However, research examining the few primitive tribes left on the planet demonstrated that a very healthy aerobic capacity, along with a lean physique, was always found without the daily 30 to 60 minutes of continuous “cardio” training that so many feel they need to endure to be lean and possess a healthy heart. Further, the biochemical make‐up of human muscle fibers is not comparable to truly superb endurance creatures. In the animal kingdom, humans, while no cheetah, are a long way from, for example, ducks that can fly vast distances without breaking a sweat.

Athletes have long been held in high regard for their physiques and fitness levels. In the early days of sports, and prior to the professionalism of current day conditioning programs, athletes simply attained their fitness from engaging in their respective sport. Well, the vast majority of sports are interval based – meaning that the activity comprises short bursts of high‐intensity exercise followed by rest or a recovery period of low‐intensity.

On many occasions, none of the sports that are offered fit the mold of a continuous endurance activity (which is not that surprising since so few sports do fit that description). When they are offered, such as distance running, cycling or swimming, they are vastly outnumbered by the deluge of sports the audience races to name. Go ahead, start naming a few of your favorites.

Perhaps you are a fan of football, baseball, tennis, golf, basketball, hockey (ice or field ‐ still the same), soccer, rugby, skiing, snow‐boarding, volleyball, or . . . I think you get the point! The vast majority of sports are interval‐based and you can get cardiovascularly fit and lose the fat by simply playing the sport, none of which, ever require engaging in moderate‐intensity continuous activity. In a very recent study published in the Journal of Strength and Conditioning Research, it was shown that the ability to perform in high‐intensity intermittent ice skating was poorly correlated to VO2 max and that VO2 max accounted for only 17.8% of the variance in performance.

However, it was further noted that the subjects did have high aerobic capacities attributable to the frequent HIIT commonly seen in hockey training. One can also simply observe athletes engaging in high‐intensity activities of short duration and appreciate the stress and subsequent training effect upon the cardiovascular system. Last years’ IAAF World Championships in Athletics (Track and Field) provided ample evidence of how cardiovascularly challenging high‐intensity, short‐duration events can be. The interviews with the winners of the 100, 200, and 400 meter sprints, events all lasting well under a minute, clearly demonstrated how out of breath the athletes were. If these events were not challenging to the cardiorespiratory system, common sense would tell you that the athletes would be able to converse without labored breathing.

Another common sense perspective is to think about the activity profiles of young children. An observational study of children playing under free‐ranging natural conditions showed a pattern of very short bursts of intense physical activity interspersed with varying intervals of low and moderate intensity.