During a HIIT workout your body shifts between bursts of intense physical activity – comprising a mix of strength exercises and cardio – and short periods of recovery. What benefits does this alternating mode of training bring to health and fitness?
the DIFFERENCE in hiit
Compared to a jog around the park, a HIIT workout is fast and furious; if undertaken with maximum effort, as little as 10 minutes is all that’s required. Yet studies suggest that those minutes of HIIT training are far more effective at burning calories and fat than hours of moderate- to low-intensity steady cardio. The reason for this is that a HIIT workout keeps the body guessing. During extended periods of cardio performed at the same pace with the same effort, the body is able to adapt and reach a metabolic state designed to conserve energy. By contrast, because HIIT causes your heart rate and energy output to fluctuate throughout an exercise session, the body fails to find this steady state and its calorie-burning energy needs remain at a higher rate. What’s more, this raised metabolic state continues for much longer during post-exercise recovery (see The HIIT “Afterburn”).
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Cardiovascular function
HIIT is a very efficient way of training your heart and improving overall cardiovascular health and fitness levels.
Muscle training
The resistance training element of HIIT stimulates growth in muscle cells, helping you to build bodily strength and power, and to develop and maintain more definition to your muscles. Building muscle also helps with weight loss and maintenance as muscle tissue burns more calories than fat tissue. (See How Muscles Work.)
Raised metabolism
The body’s metabolic system provides the energy needed to power muscle contractions during HIIT. The all-out, stop-start nature of HIIT helps keep your metabolism at a raised state for longer than continuous low-intensity exercise. (See Powering your HIIT Workout.)
Bodyweight resistance
The primary focus of physical effort in almost all HIIT exercises lies in bodyweight resistance: that is, engaging your muscles to resist the force of gravity acting on the weight of your body. The upshot of this is that HIIT requires very little equipment and can be performed at any time and almost anywhere – except perhaps on the moon!
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Immune support
Exercise contributes to overall health, which ultimately benefits the immune system. Scientists have various theories making a more direct link, but research is so far inconclusive. One theory is that increased flow of blood and lymph fluid from exercise improves the circulation of immune cells around the body. Another is that by reducing inflammation, exercise supports immune function that is compromised by states of chronic inflammation. Exercise has also been proven to reduce mental stress, which has an adverse effect on the immune system.