Exercise: Fitter Adults Have Fitter Brains

Exercise is well documented in a large body of evidence to help improve cognitive performance, including executive functioning, attention, memory, and brain structure. Physical activity has been shown to increase the size of the hippocampus among older adults, which is responsible for memory, learning, and emotion.

In this study researchers attempted to see if those same connections could be found in younger adults as well, and whether it was physical fitness and not other factors such as body weight or education that was associated with better brain health. 

Over 1,200 MRIs were examined from people with an average age of 29 who participated in the Human Connectome Project in which they took a cognitive test and completed a 2 minutes walking test designed to measure endurance. High levels of endurance were found to be positively associated with higher cognitive testing scores. 

The researchers were surprised to find visible differences between the brains of fitter and less fit people which translated to brain health and better cognitive performance. Participants who performed better in the walking tests were also found to have more white matter in their brains which contains nerve fibers that allow signals to travel faster and more efficiently, and white matter protects those nerve fibers from injury. 

The was a cross sectional study, as such the researchers can not say exactly how much or what kind of exercises would result in these specific benefits for the brain. According to the Department of Health and Human services activities such as brisk walks, biking, or housework for 150 minutes of moderate intensity is recommended. 

Next the researchers would like to include people with depression, bipolar disorder, or schizophrenia in other studies to examine whether exercise could result in similar improvements. 

"It surprised us to see that even in a young population cognitive performance decreases as fitness levels drops. We knew how this might be important in an elderly population which does not necessarily have good health, but to see this happening in 30 year olds is surprising. This leads us to believe that a basic level of fitness seems to be a preventable risk factor for brain health. This type of study raises an important question. We see that fitter people have better brain health, so we now need to ask whether actually making people fitter will improve their brain health. Finding this out is our next step. There are some trials which point in that direction, but if we can prove this using such a large database, this would be very significant.” said Dr. Jonathan Repple.

"This is an important cross-sectional study demonstrating a robust correlation between physical health and cognitive functioning in a large cohort of healthy young adults. This correlation was backed by changes in the white matter status of the brain supporting the notion that better macro-connectivity is related to better brain functioning. It stresses the importance of physical activity at all stages of life and as preliminary recent evidence suggests one can start improving physical health even in later life even if one has never trained before (see reference). These findings however need to be replicated in longitudinal studies and translated for the use in mental illness.” says Professor Peter Falkai.