Even Moderate Exercise Can Greatly Increase Brain Size

The effects are more pronounced in areas of the brain with high oxygen demand.

Exercise keeps both the body and mind healthy, but little is known about how and where physical exercise affects our brains.

“In earlier research, the brain was generally considered as a whole,” says Fabienne Fox, a neuroscientist and lead author of the current study. “Our goal was to take a closer look at the brain and find out which brain regions affect physical activity the most.”

Extensive data from the Rhineland study

Fox and his associates used information from the Rhineland Study, a large population-based study conducted by DZNE in the vicinity of Bonn, for their study. Specifically, they examined physical activity data from 2,550 people between the ages of 30 and 94, as well as magnetic resonance imaging (MRI) brain images. Research participants wore an accelerometer on their upper thigh for seven days to collect data on their physical activity. The MRIs revealed new details, particularly about the volume of the brain and the thickness of the cortex.

The more active, the greater the effects

“We were able to show that physical activity had a remarkable effect on almost all the brain regions investigated. In general, we can say that the higher and more intense the physical activity, the larger the brain regions, either with regard to volume or cortical thickness”, Fabienne Fox summarizes the research results. “In particular, we see this in the hippocampus, which is considered the control center for memory. Larger brain volumes provide better protection against neurodegeneration than smaller ones.”

However, the size of brain regions does not increase linearly with physical activity. Comparing study participants who were sedentary and those who were only moderately physically active, the research team found the largest and near-sudden increase in volume. This was especially noticeable in people over 70 years of age.

“In principle, this is very good news, especially for those who are reluctant to exercise,” says Ahmad Aziz, who heads the “Population and Clinical Neuroepidemiology” research group at DZNE. “The results of our study indicate that even small behavioral changes, such as walking 15 minutes a day or taking the stairs instead of the elevator, can have a substantial positive effect on the brain and potentially counteract age-related loss of brain matter. and the development of neurodegenerative diseases. In particular, older adults may already benefit from modest increases in low-intensity physical activity.”

Young and somewhat athletic subjects who generally engaged in moderate to vigorous physical activity also had relatively high brain volumes. However, in even more active subjects, these brain regions were slightly larger. Here too it was shown: the more active, the greater the effect, although at high levels of physical activity, the beneficial effects tended to level off.

Regions of the brain that benefit the most

To characterize the brain regions that benefited most from physical activity, the research team searched databases for genes that are particularly active in these brain areas. “Primarily, these were genes that are essential for the functioning of mitochondria, the powerhouses of our cells,” says Fabienne Fox. This means that there are particularly large numbers of mitochondria in these brain regions. Mitochondria provide energy to our body, for which they need a lot of oxygen. “Compared to other brain regions, this requires more blood flow. This is particularly well ensured during physical activity, which could explain why these brain regions benefit from exercise”, says Ahmad Aziz.

exercise protects

Bioinformatic analysis also showed a large overlap between genes whose expression is affected by physical activity and those affected by neurodegenerative diseases such as[{” attribute=””>Alzheimer’s, Parkinson’s, or Huntington’s. This could offer a potential explanation for why physical activity has a neuroprotective effect, the research team concludes. “With our study, we were able to characterize brain regions that benefit from physical activity to an unprecedented level of detail,” says Ahmad Aziz. “We hope our results will provide important leads for further research.”

And also approaches for everyday use: “With our results, we want to provide a further impetus to become more physically active – to promote brain health and prevent neurodegenerative diseases,” says Fabienne Fox. “Even modest physical activity can help. Thus, it’s just a small effort – but with a big impact.”

Reference: “Association Between Accelerometer-Derived Physical Activity Measurements and Brain Structure: A Population-Based Cohort Study” by Fabienne A.U. Fox, Kersten Diers, Hweeling Lee, Andreas Mayr, Martin Reuter, Monique M.B. Breteler and N. Ahmad Aziz, 2 August 2022, Neurology.
DOI: 10.1212/WNL.0000000000200884