Even moderate physical activity has a positive effect on the brain. DZNE researchers led by Dr Ahmad Aziz deduce this from examinations of 2,550 participants of the Bonn "Rhineland Study." According to their findings, certain areas of the brain are larger in physically active individuals than in those who are less active. In particular, brain regions that have a relatively high oxygen demand benefit from this effect. The research results are published in Neurology®, the medical journal of the American Academy of Neurology, per ScienceDaily
Exercise keeps the body and minds healthy but little is known about exactly how and where physical activity affects our brains. "In previous research, the brain was usually considered as a whole," says Fabienne Fox, neuroscientist and lead author of the current study. "Our goal was to take a more detailed look at the brain and find out which regions of the brain physical activity impacts most."
For their research, Fox and colleagues used data from the Rhineland Study, a large-scale population-based study conducted by DZNE in the Bonn city area. Specifically, they analyzed physical activity data from 2,550 volunteers aged 30 to 94 years, as well as brain images obtained by magnetic resonance imaging (MRI). To sample physical activity, the study participants wore an accelerometer on their upper thigh for seven days. The MRI scans provided information, particularly on brain volume and thickness of the cortex.
"We were able to show that physical activity had a noticeable effect on almost all brain regions investigated. Generally, we can say that the higher and more intense the physical activity, the larger the brain regions were, either with regard to the volume or cortical thickness," Fabienne Fox summarizes the research results. "In particular, we observed this in the hippocampus, which is considered the control centre of memory. Larger brain volumes provide better protection against neurodegeneration than smaller ones."
However, the dimensions of the brain regions do not increase linearly with physical activity. The research team found the largest, almost sudden volume increase when comparing inactive and only moderately physically active study participants -- this was particularly evident in older individuals over the age of 70.
"In principle, this is very good news -- especially for those who are reluctant to exercise," says Ahmad Aziz, who heads the research group "Population and Clinical Neuroepidemiology" at DZNE. "Our study results indicate that even small behavioural changes, such as walking 15 minutes a day or taking the stairs instead of the elevator, may have a substantial positive effect on the brain and potentially counteract the age-related loss of brain matter and the development of neurodegenerative diseases. In particular, older adults can already profit from modest increases of low-intensity physical activity."
Young and somewhat athletic subjects who usually engaged in moderate to intense physical activity also had relatively high brain volumes. However, in even more active subjects, these brain regions were slightly larger. Also here it showed: that the more active, the greater the effect, although at high levels of physical activity, the beneficial effects tended to level off.
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. "Mainly, these were genes that are essential for the functioning of mitochondria, the power plants of our cells," says Fabienne Fox. This means that there are particularly large numbers of mitochondria in these brain regions. 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 ensured particularly well during physical activity, which could explain why these brain regions benefit from exercise," says Ahmad Aziz.