HEALTH
A study by a team of Canadian and US scientists has found that physical activity —even mild — protects against neurodegenerative diseases such as Alzheimer’s because exercise makes our brains bigger. They found just two to three days of moderate to vigorous physical activity saw a significant increase in total brain matter and in specific areas such as the temporal lobe and hippocampus. Even pedestrian, non-athletic, non-sportive activity can be neuroprotective in some cases.
Brain matter and size are all predictors of better cognitive and neurological health as we age, while neurodegenerative diseases are often found in less dense brains. It’s been known for some time that physical activity protects the brain from neurodegenerative diseases, including mild and severe cognitive impairment, Parkinson’s, Alzheimer’s and other forms of dementia. The research team wanted to know how.
That protection is largely due to brain-derived neurotrophic factor, which is released into the brain during periods of exercise where it lowers neuro-inflammation and improves synaptic connection, among other functions.
The study involved more than 10,000 participants with an average age of 54 — ranging from 18 to 97 — about half men and half women.
Participants were asked how many days of the week they engaged in ten minutes or more of ‘moderate’ or ‘vigorous’ intensity exercise. (Exercise was self-reported, which is an inevitable flaw when conducting large population studies such as this.) While previous studies quantified moderate and vigorous intensity based on heartbeats per minute, this and other newer studies simply define ‘moderate’ as being engaged in physical activity and still being able to talk, but not being able to sing. ‘Vigorous’ was defined as being in a state where only a few words could be spoken before pausing to breathe.
Using MRI brain scans, the researchers found that a higher number of days of moderate to vigorous physical activity “predicted larger normalised brain volumes in multiple regions, including total grey matter volume, total white matter volume, hippocampus, frontal cortex, parietal lobes, and occipital lobe.” The growth in the size of some of the lobes had correlative significance or p-values of 6 or higher. A score of 6 and above is typically when scientists begin to take notice of correlations.
“While 75% of participants reported doing some regular physical activity, many didn’t meet standard exercise guidelines — yet still showed brain benefits. This adds to growing evidence that even modest physical activity can protect brain health,” writes Chris Kresser, founder of the California Centre for Functional Medicine, who wasn’t involved in the study. “Notably, moderate exercise appeared more beneficial than vigorous activity, suggesting you don’t need to be a super-athlete to reap the brain benefits.”
Comments