Physcial Activity Intervention for Huntington's Disease (PACE-HD Trial)

Huntington's disease (HD) is a genetic, degenerative neurological disease that affects individuals in their third-fourth decade of life and individuals can live 15-20 years with manifest HD. The complex disease symptoms, including motor, cognitive and behavioural impairments, result in loss of functional independence and progressive escalation of healthcare costs. The personal, social and economic consequences of HD are devastating, especially as there are currently no disease modification therapies available. Environmental factors, including exercise and physical activity, have the potential to minimize the functional impact of HD. Animal models of HD have provided the first evidence that exercise has the potential to delay or alter disease progression. A range of studies in clinical populations have shown that short-term exercise (< 3 months) is well tolerated and has the potential to improve quality of life, fitness and motor impairments in HD. Despite these promising studies, there are critical knowledge gaps that prevent the intelligent application of exercise as a therapeutic intervention in HD. Firstly, there have been no prospective evaluations of the potential role of physical activity and exercise in disease modification in HD. To date, only retrospective data has suggested that lifestyle factors, including sedentary behavior, could negatively affect disease progression in HD. Secondly, it is not known if sustained exercise (> 3 months) is feasible, and if it has the potential to improve cognitive outcomes, such as has been shown in other neurodegenerative diseases. Such longer-term studies are essential to elucidate the potential for exercise to have a disease-modifying effect; the mechanisms through which such improvement may occur have yet to be explored. In this trial, the investigators will employ a systematic approach for routinely collecting prospective physical activity and fitness data and monitoring physical activity behaviour in 120 individuals with HD. The investigators will use a database to track physical activity and exercise behaviour alongside standardized disease-specific outcome measures during two annual visits. Assessment will incorporate VO2max, a surrogate measure of fitness and a direct measure of oxygen uptake related to central nervous system (CNS) function and structure, and the use of wearable technologies (Gene-activ activity monitors) that capture and quantify dose (frequency, duration, intensity) of physical activity in a large HD cohort. The investigators will further conduct a within-cohort randomized control trial (RCT) of a 12-month exercise intervention in HD, comparing a supported structured aerobic exercise training program to activity as usual. This intervention will also incorporate a physical activity coaching program developed and evaluated by our group with a view to encouraging longer term exercise uptake.