Can Aerobic Exercise Benefit the Brain in Parkinson's Disease?

Brain function of patients with Parkinson's disease improves with regular exercise. Exercise strengthens connections between different brain areas and it inhibits brain shrinkage. Control over movements also improved in patients who cycled on an exercise bike for 45 minutes three times a week for six months. 

In Parkinson's disease, dopamine-producing cells in the brain die. As a result, patients experience a variety of symptoms, ranging from slower movement to shaking of an arm or leg. A 2018 study showed that symptoms stabilized in patients who exercised intensively on an exercise bike three times a week compared to a control group that only performed stretching exercises. MRI scans were also taken of both groups of participants, the results of which have now been published in Annals of Neurology.

Stronger brain networks

Many individuals with Parkinson’s disease develop difficulty with automatic movements such as walking. This is because the part of the brain that controls these routines is affected. The researchers noticed on MRI scans that in physically active patients, brain networks were stronger between parts that had been relatively spared by Parkinson’s disease. "These parts of the brain are given a stronger role in the whole brain network. We see this as a compensation strategy of the brain: it compensates for the fact that automatic movements, such as walking, become more difficult," said Rick Helmich, neurologist and principal investigator of Radboud university medical center and Donders Institute.

Grey-matter volume in the brain stabilizes

The researchers also looked at the brain's grey-matter volume, where the cell bodies of nerve cells are located. This clearly showed that grey-matter volume remained stable over time in patients who were active on the exercise bike for six months. In the group that did stretching exercises, grey-matter volume decreased over time. Helmich: "These findings are in line with previous studies that have shown that people who exercise actively develop more connections between brain cells. This means that you train not only your muscles, but also your brain, when you exercise."

Better ability to control movements

Finally, the patients who were physically active also became better at controlling movements. Martin Johansson, PhD student and first author of the publication, explains how they were able to determine this: "We asked the participants to perform various cognitive tasks, using eye movements to measure how well patients could exercise control over automatic movements. It turned out that the physically active group performed better at this than the control group: they improved their own performance from six months earlier, while the control group did not change. On MRI scans we then saw that their performance was directly related to their fitness, measured by their lung capacity. That showed: the fitter, the greater the control over automatic movements."

Exercise is good for the brain

The researchers suspect that intense exercise improves brain function by stimulating compensatory capacity, not by slowing down Parkinson's disease. Rick Helmich: "We know that sports are good for the brain. For everyone, but certainly also for people with Parkinson's disease. These results have important implications: exercise causes changes in the brain that can reduce Parkinson's symptoms. I hope that people with Parkinson's take this as a huge motivation to exercise more. In this time of frequent lockdowns, it also emphasizes the importance of exercise and sports."

Reference: Johansson ME, Cameron IGM, van der Kolk NM, et al. Aerobic exercise alters brain function and structure in Parkinson’s disease a randomized controlled trial. Ann Neurol. Published online December 24, 2021. doi:10.1002/ana.26291

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