Can a little bit of exercise make you smarter?
Or, stated more precisely, can regular activity help slow the cognitive declines associated with aging?
A small but intriguing study suggests that the answer to those two questions is Yes. "The message from this research is that exercise is not just good for your heart, it's good for your brain," Dr. Martin Juneau, director of prevention at the Montreal Heart Institute, said in an interview. "If you're looking for a little bit more motivation to exercise, hopefully this is it."
The study, being presented Monday at the Canadian Cardiovascular Congress in Toronto, showed that a group of middle-aged, sedentary, overweight adults could, over a period of just a few months, significantly improve standard measures of cognition including the the ability to think clearly, recall and make quick decisions.
Oh, and they also lost weight, shrunk their waist size, became more flexible and dramatically improved their endurance.
Dr. Juneau, who oversees a huge facility in Montreal where patients recovering from heart surgery and the ill-effects of cardiovascular disease come for rehabilitative exercise, said he was approached by a group of individuals who wanted to participate in a popular Quebec event, Le Grand Défi Pierre Lavoie, in which small teams cycle 1,000 kilometres around Quebec to promote youth physical activity.
The researcher agreed to train them on the condition that they would become research subjects. "This is a hot topic, exercise and the brain, so we saw it as an opportunity to do some tests on regular people," he said.
None of the six team members – four men and two women – did any exercise. They were all overweight, with an average body mass index of 29 and an average waistline of 103 centimetres (well above the recommended 94 cm for men and 80 cm for women). Their average age was 49.
They also underwent a battery of tests to measure cognitive skills and use of oxygen by the brain.
Their exercise program consisted of two sessions of high-intensity interval training on stationary bicycles, one 'long' bike ride outside of about 40 minutes, and two brief weight-training sessions.
The key exercise was the interval training, which consisted of pedalling to maximum ability for 45 seconds, followed by 45 seconds rest, this for a total of 20 minutes. (The Montreal Heart Institute uses this method to help rehabilitate heart patients.)
After four months of training, the team successfully completed the 1,000 kilometre trek, with little difficulty.
Dr. Juneau said the physical changes – four kilos of weight loss and waists that were nine centimetres smaller on average – were not surprising. Neither was the sharply increased capacity to exercise, measured by VO2 max (or peak oxygen uptake).
But the researchers were surprised at the dramatic changes in blood flow to the brain and in cognition. Interestingly, the improvements in cognition mirrored weight loss: In other words, the more weight the participants loss, the sharper their brains became. "These were average people, and we saw big changes," Dr. Juneau said.
He cautioned that the study is very small – only six people. The research is now being reproduced on a much larger scale, and Dr. Juneau is confident that he will get similar results.
"In the end, cognitive decline is largely a blood vessel problem. The brain is loaded with blood vessels and if you make those healthier with exercise, you reduce the risk of decline," he said. "It's very similar to the heart." Canada's physical activity guidelines recommend that adults be moderately active – the equivalent of a brisk walk – 30 minutes a day, every day. For children, the standard is 60 minutes.
According to Statistics Canada, only 15 per cent of adults and seven per cent of children meet that minimum standard daily. In fact, the average Canadian adult spends 50 to 70 per cent of their daily lives sitting, and roughly another 30 per cent sleeping.
Research published earlier this month in the medical journal Diabetologia compared disease rates between the most active and least active adults, and it found those who were largely sedentary had a 147-per-cent increased risk of heart attack or stroke, a 112-per-cent increase in the risk of developing diabetes, a 90-per-cent greater risk of dying from a cardiac event and a 49-per-cent greater risk of premature mortality.
A total of 69,703 Canadians died of cardiovascular disease in 2009, the most recent year for which detailed data are available, according to Statistics Canada. That is 29 per cent of all deaths.