HIIT for health

26 April 2021

A team of researchers from Western Sydney University, The University of Sydney and University of British Columbia have found shorter variations of high-intensity internal training (HIIT) really does improve health. The review paper, Low-volume high-intensity interval training for cardiometabolic health,(opens in a new window) published in the Journal of Physiology, evaluated a decade’s worth of research on low-volume high HIIT for health.

The researchers found that low-volume HIIT can produce similar, and at times superior improvements in cardiorespiratory fitness, glucose control, blood pressure, and cardiac function compared to traditional aerobic exercise such as high-volume HIIT and moderate intensity continuous training. This is despite low-volume exercise taking less time commitment and requiring less energy output.

Whilst HIIT - characterised by alternating high intensity exercise and recovery periods - has gained in popularity, researchers have been studying the value of low-volume HIIT as a comparison.  Low-volume HIIT is defined as interventions in which the total time spent exercising at high intensities is less than 15-minutes (i.e. not including rest periods).

The study also showed that low-volume HIIT can be an effective form of activity for those with severe metabolic abnormalities, such as people with type 2 diabetes, and appears to be safe and well-tolerated with low adverse effects. However, further studies are needed to determine if low-volume HIIT could be undertaken as a long-term activity.

Dr Angelo Sabag, first and corresponding author on the study and a postdoctoral research fellow at NICM Health Research Institute, Western Sydney University says despite the current World Health Organization’s (WHO) physical activity guidelines and the well-known beneficial effect of exercise on cardio metabolic health, exercise continues to be a challenge for many people.

"We know from the research that over 35 per cent of adults from high-income countries are considered physically inactive; meaning they are not meeting the recommended physical activity guidelines of 150-300-minutes of moderate activity each week or 75-100-minutes of vigorous activity each week.

“While the WHO guidelines may serve their purpose at a populational level, individualised and tailored low-volume HIIT interventions delivered by appropriately trained exercise professionals may be more effective at an individual level, especially for time-poor individuals.

“This research is especially important now as people are looking for new and exciting ways to engage in regular exercise, after a year of lower physical activity due to the pandemic."

This review builds on the research team’s past study published in Diabetes Care(opens in a new window) which showed as little as 4-minutes of HIIT three times per week over 12-weeks significantly improved fat in the liver, blood glucose control and cardiorespiratory fitness in inactive adults with obesity and type 2 diabetes. They also showed that these improvements were comparable to an intervention involving 45-minutes of moderate intensity aerobic exercise.