Gym-style exercise may improve not only general health in middle age, but also brain function, according to new research presented at the Canadian Cardiovascular Congress that is taking place in Toronto from 27 to 31 October.

The study, conducted by the Montreal Heart Institute (MHI), with the University of Montreal, and the Montreal Geriatric University Institute, found that cognitive ability improved significantly in a group of six middle-aged people with increased cardiovascular risk who followed a four-month program of high intensity interval training combined with resistance training.

High Intensity Interval Training (HIIT) or High Intensity Training (HIT), is a form of exercise where you do a number of shorts bursts of intense and effortful activity alternating with short, less effortful work, such as a series of 30-second sprints with 30 seconds of walking or jogging in between.

It is not a new idea, but has come to prominence in recent years as more researchers have looked into and measured its health benefits. It came under the media spotlight in the UK in February 2012, when medical journalist Michael Mosley appeared in a TV program, where he tried a form of high intensity interval training and was pleasantly surprised by the results.

There are various forms of HIIT, depending on the intensity and duration of the effortful bursts, and fitness goals.

In this study the HIIT training the participants underwent alternated between short periods of low and high intensity aerobic exercise on stationary bicycles.

For four months, they had twice-weekly sessions of high intensity interval training combined with twice-weekly resistance training.

One of the researchers, Anil Nigam, chief of clinical care at MHI and also of the University of Montreal, says in a statement they worked with six middle-aged people who followed this program.

All six participants were overweight (their BMI was between 28 and 31) and had one or more cardiovascular risk factors. BMI is short for Body Mass Index, a measure of obesity that equals a person’s weight in kilos divided by the square of their height in meters (BMI over 30 is considered obese, 25 to 30 is overweight).

Nigam explains the range of physical and mental measurements the participants underwent:

“Our participants underwent a battery of cognitive, biological and physiological tests before the program began in order to determine their cognitive functions, body composition, cardiovascular risk, brain oxygenation during exercise and maximal aerobic capacity.”

The cognitive tests covered a range of memory and thinking exercises, such as remembering pairs of numbers and symbols.

Using very sensitive instruments, the researchers also looked at how the participants’ brains used oxygen while they exercised or did the mental tests. The instruments, which rely on near-infra red spectroscopy (NIRS), can detect minute changes in the volume and oxygenation of blood in the brain.

Cognitive function, VO2max and brain oxygenation during exercise testing revealed that the participants’ cognitive functions had greatly improved thanks to the exercise,” says Nigam.

VO2max is a measure of the body’s ability to take in, transport, and use oxygen during physical exertion. It also affects the body’s ability to provide the brain with oxygen, which in turn impacts cognitive function.

At the end of the program, the participants also had smaller waists and less fat mass around the trunk of the body.

“We also found that their VO2max, insulin sensitivity had increased significantly, in tandem with their score on the cognitive tests and the oxygenation signals in the brain during exercise,” says Nigam.

The study, which was funded by the ÉPIC Centre and Montreal Heart Institute Foundations, appears to support other recent research on the effect of exercise on the brain. Earlier this month, scientists at the University of Edinburgh reported that exercise may protect aging brains better than mental or leisure pursuits.

Written by Catharine Paddock PhD