New Study Finds Regular Running Benefits the Aging Brain
A new study published in eNeuro has found that regular running may have significant benefits for the aging brain. Researchers compared the functionality of adult-born neurons in the brains of mice that engaged in regular running to those who led a sedentary lifestyle. The findings revealed that active mice had increased synaptic input from other brain regions and exhibited less synaptic loss compared to sedentary mice. This preservation of neural connections could imply better maintenance of cognitive abilities as one ages.
Henriette van Praag, a corresponding author of the study and an associate professor at Florida Atlantic University, stated, “Long-term exercise profoundly benefits the aging brain and may prevent aging-related memory function decline by increasing the survival and modifying the network of the adult-born neurons born during early adulthood, and thereby facilitating their participation in cognitive processes.”
As human life expectancy continues to increase, the proportion of older adults in the population is also expanding. This has resulted in more people experiencing cognitive decline to various extents. The decline often first affects areas of the brain essential for learning and memory, particularly structures in the hippocampus and adjacent brain regions.
One early indicator of age-associated cognitive decline is the diminished ability to distinguish between similar events and stimuli, also known as pattern separation. This impairment correlates with a decrease in hippocampal volume and weakening connectivity between the (peri)entorhinal cortex and the hippocampus.
The researchers conducted the study to explore the effects of long-term running on the functioning of the network of new neurons in the hippocampus, which develop only in adulthood. Previous research suggested that these neurons may only be vital for a limited time, specifically during a critical 3-6 week period following their development. This timeframe appears to determine their integration into the broader neural network and the extent of their connectivity. The study was conducted on mice.
The experiment involved 18 male mice, aged 5-6 weeks at the outset. The mice were randomly assigned to one of two groups: one had access to a silent spinner wheel for voluntary running, while the other did not. The researchers recorded and analyzed the distances run by the mice.
The researchers used a retrovirus to mark neural stem cells in the dentate gyrus region of the brain. This allowed them to identify and trace connections to the adult-born neurons. Results showed that long-term running significantly modified the network of these neurons by middle age. Running led to increased inputs to these neurons from hippocampal interneurons and prevented the loss of innervation from the perirhinal cortex region of the brain. It also increased input from areas of the brain essential for memory.
Lead author Carmen Vivar of Centro de Investigacion y de Estudios Avanzados del IPN in Mexico emphasized the relevance of including exercise in daily lives and stated, “Our study provides insight as to how chronic exercise, beginning in young adulthood and continuing throughout middle age, helps maintain memory function during aging.”
Despite the important findings, it is necessary to consider the limitations of the study. The research was conducted on mice, not humans, and while the two share many physiological characteristics, results on humans may differ. Nonetheless, this study contributes to the scientific understanding of the links between physical activity and brain health.
Overall, the study suggests that incorporating regular exercise, such as running, starting from a young age and continuing into middle age, can have significant benefits for maintaining memory function during aging.