This study will evaluate the feasibility and acceptability of a clinic-based physical activity coaching intervention in people with pre-manifest and early stage Huntington's Disease (HD). Fourteen individuals with premanifest and early stage HD will be recruited to participate in a 4 month coaching intervention. Feasibility will be assessed by recruitment and retention rates, and acceptability will be assessed by participant interviews. Participants will also be evaluate at baseline and following the coaching intervention to explore preliminary efficacy in terms of physical activity, self efficacy, disease-specific motor and cognitive function, walking endurance and strength.

The investigators have previously developed and evaluated a physical activity behavioral change intervention in people with early-mid stage HD (Engage-HD). In a study conducted in the United Kingdom, self-reported physical activity, self-efficacy for exercise, and cognition were increased for those in the coaching intervention group compared to a social contact control group. This intervention has not yet been applied to individuals with pre-manifest (prior to onset of clinical symptoms) and early stage HD, where it may be most critical to engage in exercise. To date, no study has prospectively evaluated a physical activity intervention to facilitate exercise uptake in these earliest stages. This study will explore the feasibility and acceptability of the Engage-HD intervention in 14 individuals with pre-manifest and early stage HD. The intervention will entail one face-to-face coaching session (approximately 1 hour), and three remote video sessions (via secure Webex connection via computer or smart phone, or phone call if internet/smart phone is not available to participant) lasting approximately 20 minutes. Participants will also be given FitBit wearable activity monitors to allow for self- monitoring of physical activity for use during the 4-month intervention. Participants will be evaluated at baseline and again 4 months later on a range of exploratory outcomes including physical activity, self efficacy, disease-specific motor and cognitive function, walking endurance and strength. Results from this study will be used to make relevant adaptations to prepare for a multi-site randomized controlled trial.

Inclusion Criteria:

• For premanifest - Confirmatory genetic testing for Huntington disease (HD) and diagnostic confidence score of 0-3 on Unified Huntington Disease Rating Scale, indicating pre-manifest disease state. For manifest HD - Confirmatory genetic testing for HD or confirmed clinical diagnosis of HD by neurologist
• Successful completion of Physical Activity Readiness Questionnaire (PAR-Q), or medical clearance from General Practioner
• For potential participants over age 60, a minimum score of 24 on the Mini-Mental State Examination (MMSE) (completed within 3 months) will be required for capacity to consent.
• For potential participants age 60-65, successful pass of electrocardiogram screen will be required.

Exclusion Criteria:

• Musculoskeletal injury that would interfere with participation in an exercise program
• Currently participating in a structured exercise program 3 times per week or more
• Uncontrolled psychiatric or behavioral problems that would interfere with participation in an exercise program