Regular exercise to prevent cognitive decline

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Recent research reports that “Regular exercise may be the best way to keep ageing brains sharp”. It claims that even low to moderate exercise prevents the milder forms of cognitive decline in older age. Attention span, memory and concentration (known as cognitive functions) typically decline with age, becoming slower and less efficient, much as physical functions such as walking and balance do. The authors argue that these cognitive changes can become noticeable and can cause mild disability, even if a state of dementia is not reached.

It is already known that physical activity has positive effects on a wide range of health measures, reducing the risk of heart disease and stroke, diabetes, obesity, hypertension and some cancers.

The research pooled the results of 15 studies and found that low to moderate exercise, such as playing a round of golf once a week or tennis twice a week, was linked to a 35% reduction in the risk of cognitive decline. The researchers think that this could be due to physical activity increasing blood flow to the brain.

This review of observational studies was well conducted and reported. It included an analysis of over 30,000 people and it seems likely that the researchers have sourced the most important studies on this topic. Those in the study who performed a high level of physical activity were significantly more protected against cognitive decline (memory loss etc) during the follow-up, compared to people who reported being sedentary.

The researchers also looked at the effect of exercise of a low to moderate level, and found that this too protected against cognitive impairment compared to being sedentary.

The researchers claim that this is the first meta-analysis to evaluate the role of physical activity on cognitive decline among people without dementia. The results, they say, suggest a “significant and consistent protection for all levels of physical activity against the occurrence of cognitive decline”. The protective effect appears stronger for women than for men, and it is not clear why.

The study is reliable, well conducted and reported. Though the findings may be unsurprising, as some individual studies had already shown significant results, the summary of a large body of evidence adds weight to the science behind the established link between low levels of physical activity and cognitive decline.

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In another large study looking at the health of middle-aged people, researchers found that those who met physical activity recommendations of at least 2.5 hours of moderate to vigorous exercise a week had lower levels of inflammation in their body compared with people who did not get enough exercise.

Reducing levels of inflammation is important as persistent inflammation, even at relatively modest levels, is thought to contribute to the adverse effects of ageing. For example, it is thought to contribute to loss of muscle power and strength, cardiovascular disease or CVD (conditions that affect the heart and blood vessels) and depression.

Interestingly, the results were independent of body fat. This suggests that exercise was still of significant benefit for people with no, or little, previous history of exercise