High Intensity Interval Training (HIIT) could prevent cognitive decline in older men

By Lois Zoppi, B.A.Reviewed by Kate Anderton, B.Sc. (Editor)Jul 16 2019

Age-related cognitive conditions such as dementia could be kept at bay with high-intensity interval training (HIIT). A study by the University of Queensland concluded that high-intensity interval exercise may be more effective at encouraging blood flow in the brains of older adults than continuous exercise.

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HIIT is a type of cardiovascular exercise during which people reach between 80 to 100 percent of their maximum heart rate. In between each spurt of high-intensity exercise is a short rest period.

It has previously been claimed that HIIT leads to elevated excess post-exercise oxygen consumption when compared to continuous exercise, meaning that after a person has stopped exercising, their body will continue to burn calories at an increased rate. However, the evidence for this limited.

This new research, called Cerebral Blood Flow During Interval and Continuous Exercise in Young and Old Men and published in Medicine & Science in Sports & Exercise, focused on the short-term increases in brain blood flow during HIIT workouts.

It was carried out in collaboration with Associate Professor Christopher Askew at the University of the Sunshine Coast and neuroscientists at the German Sport University Cologne and was the first of its kind.

The study compared middle cerebral artery blood velocity (MCAv), end-tidal CO₂ (P_ETCO_2, measuring the amount of carbon dioxide in an exhaled breath) and blood pressure between continuous and interval cycling in 11 men around the age of 25, and 10 men of around 69 years of age.

As we age, the flow of blood to the brain and arterial function decreases. These factors have been linked to a risk of cognitive decline and cardiovascular events, such as stroke. Finding ways to increase brain blood flow and function in older adults is vital.”

Dr. Tom Bailey, University of Queensland

HITT improves blood flow, but resting is also important

The results of the study showed that middle cerebral artery velocity was higher in young men during continuous exercise when compared with older men and interval exercise. Mean arterial pressure was similar between both groups of men but increased during continuous exercise over interval exercise.

The study concluded that interval training “may be an effective alternative for promoting acute increases in [cerebral blood flow] velocity, particularly in those older adults who may have difficulty sustaining continuous exercise.”

“One of the key takeaways from the study was that both the exercise and the rest period were important for increasing brain blood flow in older adults,” Dr. Bailey said.

This study shows that interval-based exercise was as effective as continuous exercise for increasing brain blood flow in older adults during the periods of activity, and more effective than continuous exercise when we measured the overall blood flow increases during both the exercise and the rest periods."

Dr. Tom Bailey, University of Queensland

Baily continued, “The benefits of exercise on brain function are thought to be caused by the increase in blood flow and shear stress, the frictional force of blood along the lining of the arteries, which occurs during exercise."

The researchers will now investigate the benefits of interval training on long-term brain health.