No current pharmacological therapies have the ability to stop or delay progression of Parkinson's disease, but the ability of exercise interventions to accomplish this are currently under investigation. Preclinical studies have found that exercise can reduce the loss of dopamine-generating brain cells in animal models of Parkinson's disease.[1] A human randomized controlled trial demonstrated that exercise can have positive effects on the brain in people with Parkinson's disease as well, at least in part through increased dopamine release and by promoting neuroplasticity.[2]
Exercise-induced improvements in motor function have also been found in trials of people with Parkinson's disease. A phase 2 randomized controlled trial compared the effects of high-intensity interval training (HIIT) or lower-intensity exercise on a treadmill in people recently diagnosed with Parkinson's disease to a control group that received standard care only. The HIIT exercise group had significantly less decline in motor function over a 6 month period compared to the the low-intensity exercise group and non-exercising standard care group.[3] Neither the standard care group nor the low-intensity exercise group showed improvements in disease progression, however.
A meta-analysis of 18 randomized controlled trials on the effect of exercise interventions in people with Parkinson's disease also found significant improvements in measures of motor function for exercise interventions in people with Parkinson's, compared to non-exercising or recreational-activity-only control groups. However, there were no significant improvements in non-motor Parkinson’s symptoms.[4]
Overall, the growing body of research on exercise and Parkinson’s disease suggests that exercise may significantly slow disease progression, but more research is needed to better understand the type of exercise and intensity level that may be optimal in different individuals. Parkinson's disease also tends to present as different clinical subtypes in different individuals,[5] and it isn’t currently clear which subtypes may benefit the most from exercise interventions. The overall positive body of evidence has prompted the creation of evidence-based fitness programs designed to improve physical function and delay[6] disease progression in people with Parkinson's.