Exercise for Parkinson’s disease

Parkinson’s disease (PD) is associated with degeneration of dopamine-producing neurons within the substantia nigra pars compacta. These neurons regulate voluntary and involuntary movement, and cognition.¹

Preclinical research shows that exercise can conserve dopamine neurons in rat and mouse models of PD. For example, aerobic exercise can preserve dopamine neurons through multiple mechanisms, including increased brain-derived neurotrophic factor (BDNF), decreased oxidative stress and improved mitochondrial function.^2,3 These benefits could improve the ‘motor reserve’ in individuals with PD, and lower the risk of developing PD.

Whether exercise is undertaken before or after animals are induced to develop PD seems to make no difference to its protective ability:

Exercise applied before intracerebral administration of dopamine neuron toxins in rodents can reduce dopamine cell death⁴; exercise following administration of the same toxins can improve dopamine neuron survival^3,5,6

It is noteworthy that these studies did not permit a sufficient period of time for cell death to be completed.^3,5,6 Thus, an implication from this research is that exercise can protect living dopamine cells rather than restore cells that are dead.

Can exercise lower the risk of Parkinson’s disease?

In a study, 143,325 individuals with a mean age of 63 years were followed over a 9-year period. At baseline, individuals in the highest category of weekly moderate to vigorous recreational physical activity, such as stationary bike or tennis, had a 40% lower relative risk of developing PD than those not active.⁷ Only moderate to vigorous activity, compared with light activity, was associated with PD risk.⁷

In a prospective study, the authors followed 48,574 men and 77,254 women who gave information on physical activity in 1986 or in early adulthood. In men, greater baseline physical activity was associated with a lower PD risk. Compared with men who regularly exercised ≤2 months/year, men with ≥10 months of strenuous exercise in early adult life had a 60% lower PD risk (RR=0.4; P=0.005). For women in the study, physical activity was not associated with an increase or decrease in PD risk. However, PD risk was lower in women who reported strenuous exercise during early adulthood.⁸

Exercise for treating Parkinson’s disease symptoms

• A meta-analysis in people with PD compared with controls shows that exercise improved:⁹
  • Faster timed up-and-go speed (standardised mean difference [SMD], −0.41; 95% CI, −0.61 to −0.22)
  • Scores on the Berg Balance Scale (SMD, 0.99; 95% CI, 0.76–1.23)
  • Gait: longer stride length (SMD, 0.32; 95% CI, 0.03–0.61), gait velocity (SMD, 0.49; 95% CI, 0.20–0.78)
  • Distances achieved on the six-minute walk test (SMD, 0.35; 95% CI, 0.13–0.56)
• Aerobic exercise improved PD-related motor symptoms, compared with controls, according to Part III of the Unified Parkinson’s Disease Rating Scale (SMD, −0.40; 95% CI, −0.55 to −0.24)⁹

Exercise for neurodegenerative disease: A medical panacea?

Exercise can reduce the risk of developing PD, improve motor symptoms associated with the disease, and could extend the life of living dopamine-producing neurons that can degenerate. Exercise is an intervention available to almost every individual, and amenable for integration into PD treatment plans. Could it be a medical panacea for neurodegenerative diseases?