New research has shown a benefit of regular exercise on cognitive impairment—and that might help reduce the risk of dementia in elderly populations. Activity has been shown to protect against vascular cognitive impairment, which is the second most common cause of dementia after Alzheimer’s disease. To learn more about how exercise might be able to ward off dementia, we chatted with study author Teresa Liu-Ambrose, PhD, PT, who is an Associate Professor and the Canada Research Chair at the Mowafaghian Centre for Brain Health at the University of British Columbia.
Liu-Ambrose explains that the study showed a small reduction in vascular cognitive impairment, which is impairment caused by a disease of the blood vessels in the brain. “For example, a stroke can be a cause of vascular cognitive impairment,” she says. “In our study, we worked with individuals who had vascular cognitive impairment largely due to disease of the small blood vessels of the brain.”
Published in the latest online issue of Neurology, the research looked at 70 elderly subjects who were already dealing with the effects of vascular cognitive impairment. Half of the participants took part in one-hour exercise classes three times a week for six months. The other half received information each month about vascular cognitive impairment and a healthy diet, but no information on physical activity. At the end of six months, the participants were all assessed.
Animal studies have already shown that exercise results in the release of a growth factor called brain derived neurotrophic factor (BDNF). “BDNF promotes neuron growth, differentiation, and survival,” she explains. And exercise specifically increases BDNF expression in the hippocampus, which she says is a major brain region responsible for learning and memory. In previous studies, it has been shown that exercise can increase the volume of the hippocampus—so, if exercise increases the size of the hippocampus and increases BDNF expression, that means exercise keeps your brain in better shape.
The subjects who exercised had a small improvement on the test of overall thinking skills compared to those who did not exercise. “This result, while modest, was similar to that seen in previous studies testing the use of drugs for people with vascular cognitive impairment,” Liu-Ambrose says. It’s still a minor difference, she notes, but any positive non-drug-related intervention is a good sign. And the exercising group also improved compared to the other group in their blood pressure and on a test of how far they could walk in six minutes, so overall health improved as well.
Stepping back to how you can prevent problems as you age, there isn’t one specific type of exercise Liu-Abrose recommends for people. Most research has been done on aerobic training like cycling, though, and she adds that even without the results of this study, exercise in general—in any form—as we age becomes steadily more important. “We need to be cognizant that exercise in general is good for physical health, and a physically healthy body is critical for a healthy brain,” she explains. “Specifically, many chronic conditions that we develop in midlife and onwards, such as high cholesterol, blood pressure, and Type 2 diabetes, all contribute to one’s dementia risk.”
Liu-Ambrose recommends beginning regular exercise as early in life as possible, but even latecomers to sport will benefit. “I encourage everyone to view their physical and cognitive health as investments,” she says. She likens it to saving for retirement: the earlier you start, generally, the larger the nest egg you’ll have. “The same principle likely applies to our physical and cognitive health—we should all aim to build our reserve throughout the life span to have the best change to age well.”