Physical activity and the brain
As everyone knows, physical activity is good for you. It has obvious and well known benefits for your physical health, including lower blood pressure, reduced risk of stroke and dementia, and better muscle and bone structure, particularly among older adults. Less well known is that physical activity also benefits mental health, reducing stress, depressive symptoms and anxiety. Moreover, physical activity has also been shown to reduce age-related cognitive decline, probably by improving brain health, such as slowing down age-related brain changes.
Two recent studies from CamCAN, one of LifeBrain’s UK cohorts, highlight the link between physical health and brain health. In the first study , subjective reports of greater daily physical activity were associated with greater preservation of the white matter (fibres that connect different parts of the brain) in frontal parts of the brain. These regions are important for planning, decision making, and controlling behaviour. Furthermore, the results showed that better preserved white matter within these regions was associated with better preserved cognitive speed in older people. This demonstrates the importance of white matter integrity for maintaining cognitive health into old age.
A second study  explored an objective factor that benefits from physical activity: cardiovascular health, as measured by blood pressure and heart rate. Supporting the above study, a strong relationship was observed between cardiovascular health and white matter in the brain. Using a global measure of white matter health (Figure 1), individuals with lower systolic blood pressure (the upper bound of blood pressure), lower heart rate, and a smaller difference between systolic and diastolic pressure (the lower bound), tended to have less white matter damage. Indeed, each of the factors in this study made an independent contribution to white matter health. In other words, a high heart rate was associated with poorer brain health above and beyond high blood pressure. These results highlight the importance of cardiovascular risk factors for brain health across the adult lifespan, and suggest that systolic blood pressure, diastolic blood pressure and heart rate affect white matter health via separate mechanisms.
Figure 1. Example of white-matter damage, which increases with age, but decreases with good cardiovascular health. The bright spots in the brain, highlighted in yellow, are white matter hyperintensities – areas of the brain where the tissue has been damaged. Individuals with worse cardiovascular health have more and larger hyperintensities.
These two studies support public health recommendations about the benefits of leading a physically active lifestyle across the life span, including into old age.