Modern Health - Short on time and energy? Why high-intensity interval training works and the science behind it

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Intense intervals as short as six minutes a day can improve cardiovascular fitness, build strength and is linked to sticking with fitness.

High Intensity Interval Training (HIIT) is the opposite of a monotonous workout on an elliptical trainer for one hour. This is considered steady state training where the heart is elevated between 135-160 for 30-60 minutes. HIIT involves exercising at a high intensity at about 80-95 per cent of your maximum heart rate at level that can’t be maintained for longer periods and includes resting in between intervals. 

Extensive Research and Science Behind HIIT 

Research from Canada, the US, England and Japan show that alternating between high intensity and low intensity exercise has many benefits from increased aerobic and anerobic capacity to abdominal fat loss.

The Journal of Applied Physiology did a two-week study to examine high-intensity aerobic interval training sessions completed by moderately active women 22 and 65 years-old. One test included a four-minute cycling interval working at 90 per cent intensity followed by rest intervals and another consisted of 60 minutes of cycling at a steady state. They found that HIIT increased the body and muscle capacity for fat oxidation during exercise.

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Some of the most profound research of aerobic and anerobic benefits of HIIT training was done by Dr. Izumi Tabata from the National Institute of Fitness and Sports in Japan. They studied elite athletes on stationary bicycles and found dramatic physiological benefits of HIIT. After six weeks, Dr. Tabata noted a 28 per cent increase in anaerobic capacity and a 14 per cent increase in their ability to consume oxygen V02 Max (how much oxygen your body can absorb during exercise). He concluded that four minutes of HIIT training could do more to boost aerobic and anerobic capacity than one hour of steady state exercise.

Building on this study, Mindy Mylrea’s American team conducted studies and found that one six-minute workout produced five times the calorie burn after the workout was over. That means that 50 calories are burned in the six-minute workout but an additional 250 calories are burned during the next 24 hours. This is equivalent to what is typically burned off in 30 minutes of steady state exercise. This occurs because of Excess Post-Exercise Oxygen Consumption (EPOC), the amount of oxygen consumed after exercise is complete.

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HIIT training is also more effective at reducing abdominal fat than regular aerobic exercise. The Journal of Obesity found that HIIT training can reduce fat in overweight individuals. 

There are even benefits to people with heart disease. The Mayo Clinic studied folks with heart disease who completed 20-40 second intervals on bikes. They found that their ability to slow down their heart rate to normal after exercise improved. Other studies have shown that HIIT training can improve chronic conditions such as diabetes.

People performing HIIT training are more likely to stick with exercise, according to The Mayo Clinic. They studied people doing walking intervals and found that every participant kept up with their goal of four interval walking workouts a week for four months.

In summary, HIIT workouts can have benefits in weight loss, cardiovascular health and sticking to exercise. Next week learn more about who can do HIIT training. 

About Kimberly Hicks-Ruttan
I’m the founder of Fit2Move - virtual fitness in your home, on your own time. I am a certified fitness instructor and personal trainer.
Connect with me on Facebook where I run a FREE group called Fit Tips with Kimberly or try a class on my onpodio website.