High intensity interval training for Parkinson's disease: A scoping review of systemic effects and physiological adaptations

BackgroundHigh intensity interval training (HIIT) involves vigorous intensity exercise bouts interspersed with low intensity bouts. Despite growing interest, the optimal dosage and clinical adaptability of HIIT in Parkinson's disease (PD) remain unclear. This scoping review synthesized the literature on systemic adaptations underlying HIIT in PD and developed a clinical framework while considering chronotropic incompetence, orthostatic hypotension, and disease progression.MethodsThree databases were searched for studies that incorporated HIIT interventions in PD. The Template for Intervention Description and Replication checklist was used to characterize the quality of intervention reporting.ResultsA total of 285 studies were screened, of which 10 studies were included. HIIT was administered 2-3 times/week for 30-60 min/session over 8-12 weeks. Seven studies used moderate-volume HIIT and three studies used high-volume HIIT protocols. The quality of intervention reporting was fair to good. HIIT improved cardiorespiratory fitness, motor severity, and functional mobility in PD, however, improvements were comparable to moderate intensity continuous training (MICT). HIIT may facilitate neuroplasticity by increasing brain-derived neurotrophic factor levels and dopamine transporter uptake. We recommend that HIIT programs for individuals with autonomic dysfunction use individualized heart rate targets, and perceived exertion for determining exercise intensity, and incorporate longer duration programs (>12 weeks).ConclusionHIIT is a well-tolerated intervention that may improve cardiorespiratory fitness, disease severity, and certain neurobiological markers in mild-moderate PD, with benefits similar to MICT. Larger trials comparing different HIIT volumes are needed to identify optimal exercise volume to inform individualized exercise prescription.