The brain already benefits from moderate physical activity

Summary: Moderate physical activity is associated with increased volume in brain regions associated with memory, particularly in older adults. According to researchers, light to moderate physical activity may have neuroprotective properties.

A source: DZNE

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

“In previous studies, the brain was usually considered as a whole,” says Fabien Fox, a neuroscientist and lead author of the current study.

“Our goal was to look more broadly at the brain and see which areas of the brain are most affected by physical activity.”

Detailed information from the Rhineland Survey

For their study, Fox and colleagues used data from the Rhineland Study, a large-scale population-based study conducted by DZNE in the Bonn metropolitan area. Specifically, they analyzed physical activity data and magnetic resonance imaging (MRI) brain images of 2,550 volunteers between the ages of 30 and 94.

To sample physical activity, study participants wore accelerometers on their upper thighs for seven days. MRI scans, in particular, provided information on 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 has a noticeable effect on all studied areas of the brain. In general, we can say that the higher and more intense the physical activity, the larger the brain regions were in terms of size or cortical thickness,” Fabien Fox summarizes the results of the study.

“Specifically, we observed this in the hippocampus, which is thought to be the memory control center. A larger brain size protects against neurodegeneration better than a smaller one.

However, the size of brain regions does not increase linearly with physical activity. The research team found the largest, almost sudden, increase in volume when comparing inactive and moderately physically active participants — and this was particularly evident in older adults over 70 years of age.

“Essentially, this is very good news, especially for people who don’t want to exercise,” says Ahmad Aziz, who leads the Population and Clinical Neuroepidemiology research group at DZNE.

“The results of our research show that even small changes in behavior, such as walking 15 minutes a day or taking the stairs instead of the elevator, have a significant positive effect on the brain and can counteract the age-related loss of brain matter and the development of neurodegenerative diseases. In particular, the elderly people can benefit from simple increases in low-intensity physical activity.

Younger and less athletic subjects, who mostly engaged in moderate to vigorous physical activity, had relatively higher brain volumes. However, these brain regions were slightly larger in the more active subjects. It also showed here: the more active, the greater the effect, but at higher levels of physical activity, the beneficial effects decreased.

The brain regions that benefit the most

To characterize the brain regions that benefit most from physical activity, the research team searched databases for genes specifically active in these brain regions.

“Essentially, these were genes necessary for the functioning of mitochondria, the power plants of our cells,” says Fabien Fox.

This means that these regions of the brain have a particularly large number of mitochondria. Mitochondria provide our body with energy, which requires a lot of oxygen.

The research team found the largest, almost sudden, increase in volume when comparing inactive and moderately active participants — this was especially evident in older adults over 70 years of age. Image is in the public domain

“Compared to other areas of the brain, this requires increased blood flow. This is particularly well supplied during physical exercise, which explains why these areas of the brain benefit from exercise,” says Ahmad Aziz.

Exercise Protects

Bioinformatic analysis further showed that there is a large overlap between genes whose expression is affected by physical activity and genes affected by neurodegenerative diseases such as Alzheimer’s, Parkinson’s or Huntington’s disease.

This may explain why physical activity has a neuroprotective effect, the research team concluded.

“With our research, we were able to characterize the brain regions that benefit from physical activity in unprecedented detail,” says Ahmad Aziz. “We hope that our results will provide an important avenue for further research.”

And also methods for everyday use: “With our results, we want to give another incentive to be physically active — to improve brain health and prevent neurodegenerative diseases,” says Fabien Fox. “Simple physical activity also helps. So it’s a small effort, but it has a big impact.”

See also

It shows brain and red blood cells

This is about exercise and brain health research news

Author: Press service
Source; DZNE
The connection: Press service – DZNE
Photo: Image is in the public domain

Original research: Closed access.
“Association between accelerometer-derived measures of physical activity and brain structure: a population-based cohort study” Fabienne AU Fox et al. neurology


Abstract

Association between accelerometer-derived measures of physical activity and brain structure: a population-based cohort study

Background and objectives:

Although there is growing evidence that physical activity improves neural health, studies examining the relationship between physical activity and brain morphology remain inconclusive. We therefore investigated whether objective quantitative physical activity was associated with brain volume, cortical thickness, and gray matter density in a large cohort study. Additionally, we evaluated the molecular pathways that may underlie the effects of physical activity on brain morphology.

Methods:

We used cross-sectional baseline data from 2,550 eligible participants (57.6% female; mean age: 54.7 years, range: 30–94 years) from a prospective cohort study. Physical activity dose (metabolic equivalent hours and steps) and intensity (sedentary, light-intensity, and moderate-intensity activities) were recorded with accelerometers. Brain volume, gray matter density, and cortical thickness measurements were obtained from 3T MRI scans using FreeSurfer and Statistical Parametric Mapping. The relationship between physical activity (independent variable) and brain structure (outcome) was tested by polynomial multivariable regression, adjusting for age, sex, 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.

Results:

Physical activity dose and intensity were independently associated with greater brain volume, gray matter density, and cortical thickness in several brain regions. The effect of physical activity on brain volume was evident at low levels of physical activity and differed between men and women and age. For example, more time spent in moderate- and vigorous-intensity activities was associated with greater gray matter volume, but this association was balanced by greater activity (standardized ß [95% confidence intervals]: 1.37 [0.35, 2.39] and -0.70 [-1.25, -0.15] for linear and quadratic terms). The strongest effects of physical activity were observed in motor regions and cortical regions enriched for genes involved in mitochondrial respiration.

Discussion:

Our findings suggest that physical activity benefits brain health, with the strongest effects in active areas and areas with high oxygen demand. Young adults may especially benefit from additional high-intensity activity, while older adults may benefit from light intensity. Physical activity and reduced sedentary time may be important in preventing age-related brain atrophy and neurodegenerative diseases.

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