Even moderate exercise can significantly increase brain volume

X-ray anatomy of the human brain

According to the study, certain areas of the brain are larger in physically active people than in less active people.

The effects are more pronounced in areas of the brain that have a higher need for oxygen.

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

“In previous research, the brain was typically viewed as a whole,” says Fabian Fox, a neuroscientist and lead author of the current study. “Our goal was to take a more detailed look at the brain and see which areas of physical activity in the brain affect the most.”

Extended data from the Rheinland study

Fox and his colleagues used information from the Rhineland Study, a large population study conducted by DZNE in the vicinity of Bonn, for their study. Specifically, they examined physical activity data from 2,550 individuals between the ages of 30 and 94, as well as brain images obtained by magnetic resonance imaging (MRI). Research participants wore an accelerometer at the top of their thigh for seven days to collect data on their physical activity. MRI scans revealed new details, notably about the size of the brain and the thickness of the cortex.

The more active it is, the greater the effects

“We were able to show that physical activity had a marked effect on almost all the brain regions examined. In general, we can say that the greater the physical activity and its intensity, the larger the brain regions, either in terms of size or thickness of the cortex,” Fabian Fuchs summarizes the research results. “In particular, we observed this in the hippocampus, which is the control center of memory. Larger brain sizes offer better protection against neurodegeneration than smaller ones.”

However, the size of brain regions does not increase linearly with physical activity. By comparing study participants who were sedentary and those who were moderately physically active, the research team detected the largest, almost sudden increase in size. This was especially noticeable in the elderly over 70 years of age.

“In principle, this is very good news – especially for those who are reluctant to exercise,” says Ahmed Aziz, head of the Population and Clinical Neuro-epidemiology research group at DZNE. “The results of our study suggest that even small behavioral changes, such as walking for 15 minutes per day or taking the stairs instead of the elevator, may have a significant positive effect on the brain and potentially interfere with age-related brain substance loss and the development of neurodegenerative diseases. In particular, Older adults can already benefit from modest increases in low-intensity physical activity.”

Young, somewhat athletic people who typically engage in moderate to intense physical activity also had relatively high brain volumes. However, in more active people, these brain regions were slightly larger. It is also shown here: the more vigorous the activity, the greater the effect, although at high levels of physical activity the beneficial effects tend to stabilize.

The areas of the brain that benefit the most

To characterize the regions of the brain that benefit most from physical activity, the research team searched databases for genes that were particularly active in these brain regions. “Essentially, these genes were essential to the functioning of mitochondria, the power stations of our cells,” says Fabian Fox. This means that there are particularly large numbers of mitochondria in these brain regions. Mitochondria provide our bodies with energy, for which they need a lot of oxygen. Compared to other brain regions, this requires increased blood flow. “This is especially well ensured during physical activity, which may explain why these brain regions benefit from exercise,” says Ahmed Aziz.

exercise protects

Bioinformatics analysis also showed significant 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

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