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What is High-Intensity Interval Training (HIIT)?

Despite overwhelming evidence that exercise is good for us in so many ways whether is it losing weight or gaining mental strength, most of us are struggling to find the motivation to stay physically active.

Why is that?

Daniel Lieberman, a professor at Harvard University discusses in his book, Exercised: Why Something We Never Evolved to Do Is Healthy and Rewarding, why people have such difficulty exercising when they know it is healthy and even prescribed by their doctors. One reason may be that exercising by choice is a fairly novel concept within our civilization. Unlike societies of hunters and gatherers and for most of the rest of the world and throughout human history, people exercised out of necessity such as through daily chores or work, or because it was rewarding for them (e.g., dancing). He explains how exercise stresses the body, in a good way, by causing increased blood flow and greater antioxidant and anti-inflammatory activity due to the repair of cartilage and muscle after exercising. These mechanisms can lower the risk of diabetes, obesity, cancer, and even COVID-19. He discusses how, even though we have never evolved to exercise, exercise can be a rewarding and enjoyable activity.

All exercises offer benefits, and performing different types of exercises can expand the range of benefits even further. But it is important to remember that some exercise is better than none and that almost everyone can participate in some form of exercise safely.

The question is often asked—is there the best time of day to work out? A small clinical trial of men at risk for or diagnosed with type 2 diabetes participated in a 12-week exercise program. They exercised in the morning between 8:00-10:00 am (2-3 hours after breakfast), or afternoon between 3:00-6:00 pm (2-3 hours after lunch). Compared with the morning exercisers, the men who exercised later in the day showed improved insulin sensitivity, lower fasting blood glucose, decreased fat mass, and better exercise performance. The authors did not speculate on reasons why the afternoon time produced significantly greater benefits, other than a major role our body clocks, or circadian rhythms, may have on metabolism. Circadian rhythms are regulated by light and darkness and affect energy levels, sleep, alertness, and hormone levels.

A specific type of exercise called High-Intensity Interval Training (HIIT) incorporates multiple rounds of exercise that alternate between several minutes of high-intensity movements to significantly increase the heart rate to at least 80% of one’s maximum heart rate, followed by short periods of lower intensity movements.

Body weight can be used as the main form of resistance so additional equipment is not needed. HIIT workouts also generally do not require a large amount of space, making the format ideal for a home workout. HIIT workouts can be integrated into various exercise formats, such as running (outdoors or on a treadmill), dancing, rowing machines, stationary bicycles, or stair climbers. The interval durations can be timed by using one to five-minute music tracks. HIIT can help to decrease body fat, increase strength and endurance, and improve health outcomes. Its main appeal is that it can achieve similar fitness and health benefits in a shorter duration and that it includes periods of rest.

Although initially applied to athletes to improve their performance, HIIT is now included as a potential exercise option for individuals with chronic diseases. It can help to improve their physical functioning, exercise tolerance, and quality of life. Importantly, because of the higher intensity format, it is advised to consult with a physician if you have any medical conditions before starting a HIIT program.

Furthermore, all participants new to HIIT should choose a program that is facilitated by an exercise professional. This is where TGHC can help. All our exercise coaches are expert at all forms of fitness routines and especially on HIIT. We hope that you will take advantage of this and put yourself sustainably on the track of lifelong health and fitness.


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