High-Intensity Interval Training; efficient and effective Once upon a time, humans expended large amounts of energy in efforts to maintain shelter and find food and water. Fast forward about 700 years through the agricultural and Industrial Age to the digital age, and we find ourselves in a world of mechanical transport, screen-based pastimes and barriers to exercise. Never has there been a more important time for humans to exercise. But what form of exercise is best? The answer depends on your body type, age, preference, access to resources, finances, location, skills and availability of time. But regardless of all of these things, everyone is in agreement that we need to be doing something active. Over the past decade, high-intensity interval training (HIIT) has become popular worldwide. Perhaps it’s a reincarnation of aerobics in the 80s with a few tweaks and changes, but there is a possibility that it is something new altogether. The evidence is in Personally, I think HIIT training is excellent. There is an enormous body of evidence that would agree. HIIT has two key ingredients that make just about any training program effective. Intensity Whether it be the group training environment, the structured work: rest intervals carefully designed to allow you to work hard, recover, then work again or the specific design of the exercises, most HIIT sessions are achieving high levels of intensity. A lot of gyms now have technology so that this can be measured and displayed in real-time with devices like heart rate monitors. Intensity is critical as it appears to stimulate more muscle growth, fat loss and cardiorespiratory adaptation than conventional aerobic exercise. We need to shake off the old mentality of targeting the “fat burning zone” (40-60% of max heart rate) and start to aim for heart rates that rise up above 90% of our max, then dip back down and repeat this cycle many times throughout the session. I have seen too many unsuccessful programs which so often lack the key ingredient of intensity, but still, induce the same (if not more) wear and tear on the body. Variability Variability means the lack of constancy and consistency. It’s critical to keep that variability in our exercises for a couple of reasons. If we are constantly changing the type of exercise, the speed of exercise, the muscles used and the joint angles, we are far less likely to suffer from overuse injuries. Less injury equates to more time training and better results. Secondly, by continually changing the exercises we don’t allow the body to get used to any one type of movement, thereby creating a need for constant adaptation of muscle fibres, blood vessels, oxygen carrying capacity etc (the list goes on, trust me). Applicable to all areas of exercise This principle also applies to runners and other exercises. By changing the distance of reps, the speed, the incline and the recovery periods, you will get the same profound effect and it usually trumps continuous moderate-intensity exercise. On the flip side, by training the same exercises over and over again, our body very quickly adapts to be able to perform this type of training with very little effort. Less effort means less energy expended, less adaptation of muscle fibres and less stimulus for change of the cardiovascular system. In all, less improvement So whether it be group classes, running, resistance training, aerobics the final word is simple. Keep your body guessing with intensity and variability and you’ll get great results! All the best with your training!