After 30 days of free access to the running wheel, adult mice descended vertical poles faster and moved more actively in an open arena than their peers whose wheels were locked...

Running improves mobility not only in young but also in older individuals. This conclusion was reached by researchers at NYU Langone Health while studying the effects of physical activity on the brains of middle-aged mice.

Regular running increases dopamine (a key neurotransmitter for movement, motivation, and memory) release as effectively in older mice — equivalent in age to humans over 50 — as in “young” animals. The study was published in the journal npj Parkinson.

Previously, the aforesaid researchers had found that the young rodents showed a steady increase in dopamine levels after one month of voluntary running. It is now shown that 12-month-old mice, an age when age-related changes begin to appear among animals, respond in the same way — and sometimes even more strongly.

After 30 days of free access to the running wheel, adult mice descended vertical poles faster and moved more actively in an open arena than their peers whose wheels were locked. But grip strength did not differ between both groups, indicating that the improvements are related to coordination rather than muscle strength.

 “Our findings make clear that the impact of exercise on brain health and mobility is not exclusive to the young,” said study senior author Margaret E. Rice, PhD. “By getting enough physical activity, we can still heighten dopamine release to help us move faster and more easily.”

The effect was observed in both male and female mice. Females ran twice as much as males, but the increase in dopamine release was the same, which, according to the researchers, suggests the presence of a threshold effect: once the body reaches the necessary activity level, further increases in dosage do not enhance the effect.

This study is particularly important for understanding the mechanisms of Parkinson’s disease, where dopaminergic neurons gradually degrade, causing slowed movements, tremor, and balance impairment. It has long been known that physical activity helps mitigate symptoms of Parkinson’s disease, but the biochemical reasons remained unclear.

“These results provide neurochemical evidence for why exercise improves everything from memory to movement to mood, all of which are affected in people with Parkinson’s disease,” Rice added.

The aforesaid researchers now plan to repeat the experiment in genetic models of Parkinson’s disease, and eventually extend the study to humans to understand how enhanced dopamine release can specifically slow the Parkinson’s disease progression.