Summary: Moderate physical activity has been linked to increased volume in areas of the brain associated with memory, especially in older adults. Researchers say light to moderate physical activity may have neuroprotective properties.
Exercise keeps the body and mind healthy — but little is known about exactly how and where physical activity 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.”
Comprehensive data from the Rhineland study
In their research, Fox and colleagues used data from the Rheinland Study, a large-scale population study conducted by DZNE in the Bonn City District. Specifically, they analyzed physical activity data from 2,550 volunteers aged 30 to 94, as well as brain images obtained by magnetic resonance imaging (MRI).
To sample physical activity, study participants wore an accelerometer at the top of their thigh for seven days. MRI scans provided specific information about the size of the brain and the thickness of the cortex.
The more active you are, the greater the effects
“We were able to show that physical activity had a marked effect on almost all of 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,” summarizes Fabian Fuchs’ results search.
“In particular, we observed this in the hippocampus, which is the control center for memory. Larger brain sizes offer better protection against neurodegeneration than smaller ones. “
However, the dimensions of brain regions do not increase linearly with physical activity. The research team found almost the largest sudden increase in size when comparing inactive and only moderately active study participants – this was particularly evident in older individuals 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 15 minutes a 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 necessary for the functioning of mitochondria, the power plants in 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.
Bioinformatic analysis further showed that there is significant overlap between genes whose expression is affected by physical activity and those affected by neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease or Huntington’s disease.
The research team concluded that this could offer a possible explanation for why physical activity affects nerves.
“Through our study, we were able to characterize the regions of the brain that benefit from physical activity with an unprecedented level of detail,” says Ahmed Aziz. “We hope our findings will provide important clues for further research.”
Also approaches for everyday use: “With our findings, we want to provide additional motivation to become more physically active — to boost brain health and prevent neurodegenerative diseases,” says Fabian Fox. “Even modest physical activity can help. Thus, it is just a small effort – but it has a huge impact.”
About this exercise and brain health research news
author: press office
Contact: Press office – DZNE
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“Association between accelerometer-derived physical activity measurements and brain structure: a population-based cohort study” by Fabienne AU Fox et al. Neurology
Correlation between accelerometer-derived physical activity measurements and brain structure: a cohort population study
Background and goals:
While there is growing evidence that physical activity enhances neuronal health, studies examining the relationship between physical activity and brain morphology remain inconclusive. We therefore examined whether objective quantitative physical activity was associated with brain size, cortical thickness, and gray matter density in a large cohort study. In addition, we evaluated the molecular pathways that may underlie the effects of physical activity on brain morphology.
We used cross-sectional baseline data from 2550 eligible participants (57.6% of women; mean age: 54.7 years, range: 30–94 years) from a prospective cohort study. The dose of physical activity (equivalent metabolic hours and number of steps) and intensity (inactive activity, light intensity, and moderate-to-vigorous intensity activities) were recorded using accelerometers. Measures of brain volume, gray matter density, and cortex thickness were obtained from 3T MRI scans using FreeSurfer and parametric statistical plotting. The relationship between physical activity (the independent variable) and brain structure (outcome) was examined with multivariate multivariate regression, adjusting for age, gender, intracranial volume, education and smoking. Using gene expression profiles from the Allen Brain Atlas, we extracted molecular signatures associated with the effects of physical activity on brain morphology.
The dose and intensity of physical activity were independently associated with greater brain volumes, gray matter density and cortical thickness for several brain regions. The effects of physical activity on brain volume were more pronounced with lower physical activity and differed between men and women and across age. For example, more time spent in moderate to intense intensity activities was associated with increased total gray matter volume, but the relationship stabilized with more activity (normative ß). [95% confidence intervals]: 1.37 [0.35, 2.39] and -0.70 [-1.25, -0.15] for linear and quadratic terms, respectively). The strongest effects of physical activity were observed in motor and cortical regions enriched for genes involved in mitochondrial respiration.
Our findings suggest that physical activity benefits brain health, with the strongest effects in motor regions and regions of high oxidative demand. While young adults may especially benefit from additional, high-intensity activities, older adults may actually benefit from light activities. Physical activity and reducing sitting time may be critical in preventing age-related brain atrophy and neurodegenerative diseases.
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