Exercise programs that combine resistance exercise with aerobic training yield optimal health benefits for people with HIV. The global aim of this study is to contribute evidence for the impact potential of a comprehensive exercise program on brain health in people with HIV.

This study is part of a larger project based upon a cohort multiple randomized controlled design. Within a fully characterized cohort which is followed over time, people meeting the specific criteria for an exercise intervention will be identified. The sample will be randomly selected to receive the intervention; the remaining eligible persons will serve as controls. The intervention group will receive a 45 minute structured exercise program 3 times a week consisting of aerobic exercise and resistance training for a total of 12 weeks.

Exercise is an inexpensive intervention with widespread benefits to vascular and musculoskeletal health and few harms. Showing an additional benefit to brain health and cognition in particular is likely to encourage adoption and help elucidate mechanisms underpinning brain health in HIV.

The primary objective of the study is to estimate, in comparison to individuals not offered the exercise intervention, the extent to which a comprehensive exercise program impacts on indicators of brain health, where these indicators are the primary outcome of cognitive ability (B-CAM) and the related brain health outcomes of depression, anxiety, fatigue, motivation, and speed of motor performance.

A secondary objective is to estimate the extent to which changes in brain health are mediated through exercise induced changes in brain network function as measured by EEG and/or by exercise induced changes in muscle power, aerobic capacity, physical function, and body composition.

The exercise intervention will target individuals recruited from two Montreal clinics who identified at cohort entry they were interested in being approached for different trials if they eligible.

Inclusion Criteria:

• men and women aged ≥ 35 years, HIV+ for at least 1 year, able to communicate adequately in either French or English, and able to give written informed consent.

Also, participants must identify that they are mostly sedentary by reporting that they perform moderate level physical activity of 30 minutes duration less than twice a week or have limitations in performing vigorous activities, walking a kilometer, or climbing stairs. Individuals answering yes to any of the Physical Activities Readiness Questionnaire (PAR-Q) (Thomas et al., 1992) items except taking medication (Item 6) will require clearance from their physician to be included.

Exclusion Criteria:

• people with dementia (MOCA < 18) or treating physician's concern about capacity to consent, life expectancy of < 3 years or other personal factors limiting the ability to participate in follow-up, non-HIV-related neurological disorder likely to affect cognition, known active CNS opportunistic infection or hepatitis C requiring interferon (IFN) treatment during the follow-up period, psychiatric disorder on the psychotic axis, current substance use disorder or severe substance use disorder within the past 12 months.

Also excluded will be people with a contraindication for exercise from cardiovascular or musculoskeletal co-morbidity as gathered from the medical history and from the PAR-Q (Thomas et al., 1992).