Background: The benefits of exercise in PD have been linked to enhanced dopamine (DA) transmission in the striatum.
Objective: To examine differences in DA release, reward signaling, and clinical features between habitual exercisers and sedentary subjects with PD.
Methods: Eight habitual exercisers and 9 sedentary subjects completed [11 C]raclopride PET scans before and after stationary cycling to determine exercise-induced release of endogenous DA in the dorsal striatum. Additionally, functional MRI assessed ventral striatum activation during reward anticipation. All participants completed motor (UPDRS III; finger tapping; and timed-up-and-go) and nonmotor (Beck Depression Inventory; Starkstein Apathy Scale) assessments.
Results: [11 C]Raclopride analysis before and after stationary cycling demonstrated greater DA release in the caudate nuclei of habitual exercisers compared to sedentary subjects (P < 0.05). Habitual exercisers revealed greater activation of ventral striatum during the functional MRI reward task (P < 0.05) and lower apathy (P < 0.05) and bradykinesia (P < 0.05) scores versus sedentary subjects.
Conclusions: Habitual exercise is associated with preservation of motor and nonmotor function, possibly mediated by increased DA release. This study formulates a foundation for prospective, randomized controlled studies. © 2018 International Parkinson and Movement Disorder Society.
Keywords: Parkinson's disease; dopamine release; exercise; function magnetic resonance imaging; positron emission tomography.
© 2018 International Parkinson and Movement Disorder Society.