What is HIIT?
HIIT is a form of anaerobic exercise (short duration, high intensity exercise) that helps you quickly use up your glycogen (carbohydrate) stores so that your body starts to burn fat for fuel. It involves any exercise that allows you to expend a large amount of energy in a short space of time. The aim is to get breathless while pushing yourself to the max for short intervals.
What does a HIIT workout involve?
It involves short bursts of high intensity exercise followed by a short period of rest and recovery. There are so many configurations and ratios of effort to rest times that you can do. An example would be a 30 second burst of effort followed by a 20 second recovery for a period of 20-30 minutes.
The latest research by Stephen Boutcher at Sydney University has shown that doing a series of short, sharp intervals for a period of 20 minutes helps produce chemicals known as catecholmines. These chemicals turn on the body’s fat-burning process. Doing this training 3 times a week is so effective, its benefits equal cycling for 1 hour, 7 days a week. The end result? Greater fat loss from the legs and trunk area.
HIIT and Weight Loss
If you’re keen to kickstart fat burning or maintain a healthy weight, HIIT is a far better choice than lengthier aerobic workout sessions. Interval training burns fat and improves fitness more quickly than constant, moderate intensity physical activity, according to research by the University of Guelph in Canada. Studies show that HIIT workouts trigger substantial beneficial health impacts, including a reduction in waist circumference, particularly around the trunk and abdomen, a change to a healthier hormonal profile and greater insulin sensitivity, reducing risk of weight gain and diabetes. Moreover, HIIT workouts provide these health dividends in shorter time.
If you incorporate resistance training into your HIIT, you will build even more muscle, which is a metabolically active tissue in the body. The more lean tissue you have, the higher your resting metabolic rate, so you burn more calories even when at rest!
Effects HIIT has on your muscles.
As your muscle strength improves through anaerobic fitness, you increase the density of your muscle fibres, becoming more toned, stronger, and more able. As muscle is more metabolically active, this means you burn more calories even when at rest. Meanwhile, movements like sprinting and jumping make your bones stronger too.
Effects HIIT has on oxygen intake and circulation (heart and lungs)
Anaerobic activity trains the heart, lungs and cardiovascular system to process and deliver oxygen more quickly and efficiently to every part of the body. The stronger and more efficient your heart muscle, the more blood can be pumped with each heartbeat. This is good news for overall health. Oxygen helps the body repair cells, convert carbohydrates into energy, break down waste products and toxins and fight free radicals, which cause diseases (such as cancer).
Effects HIIT has on the mind and brain
Exercise that gets you breathless can keep your brain in good shape as well as your body and reduce the risk of dementia as you age. People also report a great sense of achievement after finishing a HIIT workout where they have pushed themselves to maximum capacity. Research at the University of Montreal has found that, after four months of HIIT, middle-aged people enjoyed greatly improved cognition and memory and also better oxygenation to the brain (which is visible on MRI brain scans). Exercise that stimulates the circulation has also been shown to increase the release of brain chemicals like serotonin, the happiness hormone.
Effects HIIT has on your general health
This kind of exercise reduces the risk of heart disease, stroke and diabetes while also lowering blood pressure and unhealthy cholesterol levels. Research from McMaster University shows that it improves the function and structure of blood vessels with particular benefits to arteries that deliver blood to our muscles and heart. Their research also found that just 6 minutes of HIIT involving sprint intervals is as effective as an hour a day of moderate exercise. As HIIT helps increase fat burning, it also reduces inflammation, which has been linked to conditions like allergy, cancer and autoimmune disease.