ObjectivesOur aim was to examine wireless physical activity monitor (WPAM) use and its associations with contextual factors (age, highest education level, social support and mental health) among adults living with HIV engaged in a community-based exercise (CBE) intervention.DesignQuantitative, longitudinal, observational study.SettingToronto YMCA, Ontario, Canada.ParticipantsEighty adults living with HIV who initiated the CBE intervention.InterventionParticipants received a WPAM to track physical activity during a 25-week CBE intervention involving thrice-weekly exercise, supervised weekly (phase 1) and a 32-week follow-up involving thrice-weekly exercise with no supervision (phase 2), completed in December 2018.Outcome measuresUptake was measured as participants who consented to WPAM use at initation of the intervention. Usage was defined as the proportion of days each participant had greater than 0 steps out of the total number of days in the study. We measured contextual factors using a baseline demographic questionnaire (age, highest education level), and median scores from the bimonthly administered Medical Outcomes Study-Social Support Scale and Patient Health Questionnaire (mental health), where higher scores indicated greater social support and mental health concerns, respectively. We calculated Spearman correlations between WPAM usage and contextual factors.ResultsSeventy-six of 80 participants (95%) consented to WPAM use. In phase 1, 66% of participants (n=76) and in phase 2, 61% of participants (n=64) used the WPAM at least 1 day. In phase 1, median WPAM usage was 50% (25th, 75th percentile: 0%, 87%; n=76) of days enrolled and in phase 2, 23% (0%, 76%; n=64) of days. Correlation coefficients with WPAM usage ranged from weak for age (ρ=0.26) and mental health scores (ρ=−0.25) to no correlation (highest education level, social support).ConclusionsMost adults living with HIV consented to WPAM use, however, usage declined over time from phase 1 to phase 2. Future implementation of WPAMs should consider factors to promote sustained usage by adults living with HIV.Trial registration numberNCT02794415.