Summary: Moderate physical activity was linked to increased volume in brain areas associated with memory, particularly in older people. 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 generally viewed as a whole,” says Fabienne Fox, neuroscientist and lead author of an ongoing study.
“Our goal was to take a closer look at the brain and find out which regions of the brain physical activity has the most impact.”
Detailed data from the Rhine study
For their research, Fox and his colleagues used data from the Rhineland Study, a large-scale, population-based study conducted by DZNE in the Bonn area. Specifically, they analyzed physical activity data from 2,550 volunteers between the ages of 30 and 94, along with brain images obtained by magnetic resonance imaging (MRI).
To sample physical activity, study participants wore an accelerometer on their upper thigh for seven days. The MRIs provided information, in particular, on the volume 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 noticeable effect on almost all the brain regions studied. In general, we can say that the higher and more intense the physical activity, the larger the cerebral regions, whether in volume or in cortical thickness”, summarizes Fabienne Fox.
“In particular, we observed this in the hippocampus, which is considered the control center for memory. Larger brain volumes 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 the largest, almost sudden, increase in volume when comparing inactive and moderately physically active study participants, which was particularly evident in people over the age of 70.
“In principle, this is very good news, especially for those who are hesitant 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 the loss of brain-related brain matter. with age and the development of neurodegenerative diseases.In particular, the elderly can already benefit from modest increases in low-intensity physical activity.
Young and somewhat athletic subjects who typically 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 showed: the more active one is, the greater the effect, although at high levels of physical activity the beneficial effects tend to level off.
The regions of the brain that benefit the most
To characterize the brain regions that benefited the most from physical activity, the research team searched databases for genes that were particularly active in those brain regions.
“These were mainly genes essential to the functioning of mitochondria, the power stations of our cells, specifies Fabienne Fox.
This means that there is a particularly high number of mitochondria in these regions of the brain. Mitochondria provide our body with energy, for which they need a lot of oxygen.
“Compared to other brain regions, this requires increased blood flow. This is particularly well ensured during physical activity, which could explain why these brain regions benefit from exercise,” explains Ahmad Aziz.
Bioinformatics analysis further showed that there is a large overlap between genes whose expression is affected by physical activity and those impacted by neurodegenerative diseases such as Alzheimer’s, Parkinson’s or Huntington.
This could offer a potential explanation for why physical activity has a neuroprotective effect, the research team concludes.
“Thanks to our study, we were able to characterize the regions of the brain that benefit from physical activity at an unprecedented level of detail”, explains Ahmad Aziz. “We hope our results will provide important avenues for further research.”
And also approaches for everyday use: “With our results, we want to give new impetus to becoming more physically active, to promote brain health and prevent neurodegenerative diseases,” explains Fabienne Fox. “Even modest physical activity can help. So, it’s just a small effort, but with a big impact.
About this exercise and brain health research news
Original research: Access closed.
“Association between accelerometer-derived measures of physical activity and brain structure: a population-based cohort study” by Fabienne AU Fox et al. Neurology
Association between accelerometer-derived measures of physical activity and brain structure: a population-based cohort study
Context and objectives:
Although there is growing evidence that physical activity promotes neural health, studies examining the relationship between physical activity and brain morphology remain inconclusive. We therefore investigated whether objectively quantified physical activity is related to brain volume, cortical thickness and gray matter density in a large cohort study. Additionally, we assessed the molecular pathways that may underlie the effects of physical activity on brain morphology.
We used baseline cross-sectional data from 2550 eligible participants (57.6% female; mean age: 54.7 years, range: 30 to 94 years) from a prospective cohort study. Physical activity dose (metabolic equivalent hours and number of steps) and intensity (sedentary, light-intensity, and moderate-to-vigorous-intensity activities) were recorded with accelerometers. Cerebral volumetric, gray matter density, and cortical thickness measurements were obtained from 3T MRI using FreeSurfer and statistical parametric mapping. The relationship between physical activity (independent variable) and brain structure (outcome) was examined with multivariate polynomial regression, while 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.
Dose and intensity of physical activity were independently associated with larger brain volumes, gray matter density, and cortical thickness of several brain regions. The effects of physical activity on brain volume were more pronounced at low amounts of physical activity and differed between men and women and by age. For example, more time spent in moderate-to-vigorous intensity activities was associated with greater total gray matter volume, but the relationship stabilized with more activity (normalized ß [95% confidence intervals]: 1.37 [0.35, 2.39] and -0.70 [-1.25, -0.15] for the linear and quadratic terms, respectively). The strongest effects of physical activity were observed in motor regions and cortical regions enriched in genes involved in mitochondrial respiration.
Our results suggest that physical activity is beneficial for brain health, with the strongest effects in motor regions and regions with high oxidative demand. While young adults can particularly benefit from additional high-intensity activities, older adults can already benefit from low-intensity activities. Physical activity and reduced sedentary time may be essential in preventing brain atrophy and age-associated neurodegenerative diseases.