A series of adverse physical and mental health effects are often reported among people living with HIV (PLWH) as a consequence of the infection and ART use. Physical activity (PA) has been linked to improved physical an mental health in PLWH. However, Most interventions in the HIV literature evaluating the effects of PA on physical and mental health have included face-to-face supervised exercise in highly controlled environments which is not representative of how the majority of this population engages in PA. Mobile application (app) and text-message based PA interventions are a safe and innovative approach for the delivery of PA programs aimed at improving physical and mental health without the need of direct supervision. Nonetheless, the use of these types of interventions have not been well evaluated in PLWH. Therefore the purpose of this study is to evaluate the effects of a 12-week mobile app and text-based PA intervention on physical and mental health in PLWH.

Participants in the PA group will be given a PA program delivered through a mobile health app which will be accessed through smartphones. As part of the program, weekly text messages will be sent to encourage PA participation. The goal of the intervention is to increase moderate to vigorous PA (MVPA) by at least 150 weekly/mins. The PA program will also include muscle strengthening exercises. Investigators expect improvements in mental health outcomes (i.e., depressive symptoms and HRQoL) and cardiometabolic outcomes (i.e., cardio-autonomic function, body fat percentage, physical activity, and functional exercise capacity) in the PA group when compared to the CON group at the end of 12-weeks.

People living with HIV (PLWH) now live longer due to the effectiveness and availability of anti-retroviral therapy (ART). However, a series of adverse physical and mental health effects are often reported in this population as a consequence of the infection and ART use. Poor mental health and health-related quality of life (HRQoL) is more prevalent among PLWH, with rates of depression as high as 42% and rates of generalized anxiety disorders. recently reported at ~19%. Research also suggests that a number of physical health and cardiometabolic side effects are associated with the disease progression and ART use, and these side effects have led to a significant increase in the risk of cardiovascular disease (CVD) among this patient population .

Among PLWH, physical activity (PA) has been linked with HRQoL , and less anxiety and depression . Furthermore, PA has also been associated with cardiometabolic health benefits , improved body composition , lower diabetes rates , functional exercise capacity , and improved cardio-autonomic function among PLWH, all which can reduce the risk of CVD. However, research suggests that lack of PA combined with sedentary behavior is prevalent among PLWH . A recent meta-analysis showed that PLWH spend approximately 98.6 minutes per day physically active, which is less than the amount reported for other chronic diseases and in general population.This is concerning since physical inactivity is one of the leading risk factors for non-communicable diseases like CVD, diabetes and cancer. Overall these results suggest that PLWH are not engaging in sufficient PA, and thus not receiving the health-related benefits associated with a physically active lifestyle.

Most interventions in the HIV literature evaluating the effects of PA in physical and mental health have included face-to-face supervised exercise in highly controlled environments. However, PA interventions that include supervision in a controlled setting may not be representative of how the majority of PLWH engage in PA. In addition, since the HIV infection is concentrated among those of lower socioeconomic status (SES), access to exercise facilities and regular supervision during PA may be difficult for most PLWH. Recently, investigators conducted a combined home and lab-based aerobic exercise intervention in PLWH and found encouraging results in the adherence rates in the home-based unsupervised sessions (i.e., >80%), suggesting that PLWH will engage in exercise even when there is no direct supervision. To date, a very limited number of studies have evaluated the effectiveness of unsupervised PA interventions in PLWH. Both studies showed that these types of interventions are safe and can be effective at improving physical and mental health outcomes in PLWH.

Mobile application (app) and text-message based PA interventions are a safe and innovative approach for the delivery of PA programs aimed at improving PA participation, reducing sedentary behavior and improving physical and mental health outcomes in a variety of populations, despite the lack of supervision inherent to this design. The use of a mobile app can promote greater engagement as it provides: 1) instructional videos of activities that the participant can safely perform without the need of supervision, 2) an interactive way for participants to track their progress towards meeting the goal volume of weekly PA, and 3) feedback on their PA participation through the integration of text-messaging. The use of text-messaging can be an effective way to provide statements to encourage PA participation, provide counseling on how to overcome barriers to engaging in regular PA and give individualized feedback on current PA participation. In addition, the widespread use of smart phones in the United States, even among those of lower SES, makes these types of interventions an accessible, easy to use and low-cost method to promote PA participation and improve health. However, the use of these types of interventions have not been well evaluated in PLWH. To the best of our knowledge, only one pilot study evaluated the effects of a mobile app exercise intervention in PLWH. Nonetheless, this study lacked a no-exercise control group, included partial supervised and did not include text messaging based on established health behavior models to promote behavior change. The proposed project is innovative as it will be the first randomized controlled trial to test the effects of a mobile app and text-message based PA intervention on physical and mental health outcomes in PLWH. Therefore, the primary aims of this study are:

1. To evaluate the effects of a mobile app and text-based PA intervention on physical health (i.e., HRQoL, perceived physical health, body composition, functional exercise capacity and cardio-autonomic function) in PLWH.

   H1: The mobile app and text-based PA intervention will improve physical health in PLWH at the end of 12 weeks when compared to the education control group.

2. To evaluate the effects of a mobile app and text-based PA intervention on mental health (i.e., depressive symptoms, perceived mental health and health related quality of life) in PLWH.

   H2: The mobile app and text-based PA intervention will improve mental health in PLWH at the end of 12 weeks when compared to the education control group.

3. To evaluate the effects of a mobile app and text-based PA program on PA participation in PLWH.

H3: The mobile app and text-based PA intervention will increase PA participation in PLWH at the end of 12 weeks when compared to the education control group.

Overview and study design The pilot study is a mobile-app and text-message based PA intervention lasting a total of 12-weeks using a randomized controlled design in which adult PLWH (n=40) will be recruited. The study will include two groups: a physical activity (PA) group and an education control (CON) no-exercise group for comparison purposes. Outcome measures will include: perceived physical and mental health, depression symptoms, HRQoL, cardio-autonomic function, body composition, functional exercise capacity and objectively measured PA and sedentary time.

Screening A phone pre-screening will be conducted for all volunteers to explain the purpose and procedures of the study and determine eligibility. Participants will also be asked to bring their most recent (≤ 6 months) CD4 T-cell, HIV viral load and HIV medications to the first lab visit for safety and to determine eligibility.

Baseline Sessions Two baselines sessions will be conducted at the beginning of the study. The baseline sessions will take place seven days apart. During the first session investigators will collect sociodemographic data, evaluate the participant's medical history and HIV status. During the first baseline session investigators will also give the participants a research-grade accelerometer to wear in order to measure their PA and sedentary time for 7-consecutive days. During the second baseline visit investigators will assess the participant's physical health and mental health, depression symptoms, HRQoL, resting heart rate variability (HRV), functional exercise capacity and body composition, and retrieve the accelerometer. The participants will be then randomized to either the PA or CON group. Before the visit participants will be instructed to not consume food, caffeine, tea or tobacco products for at least 3 h before, to refrain from consuming alcohol for at least 48 h before, and to not engage in any exercise for at least 24 h before as this may affect some of the study outcome measures.

Intervention 40 participants will be randomly assigned to either 1) a PA intervention group, or 2) an education CON group (detailed in the intervention section).

Post Intervention Sessions Two post-intervention sessions will be conducted at the end of the study to evaluate changes over time in the main study outcomes. The two sessions will take place 7-days apart. During the first post-intervention session investigators will give the participants an accelerometer to wear in order to measure their PA and sedentary time for 7-consecutive days. During the second visit investigators will assess the participants physical and mental health, depression symptoms, HRQoL, HRV, body composition, functional exercise capacity and retrieve the accelerometers.

Inclusion Criteria:

• 1) diagnosed with HIV,
• 2) receiving the same ART for at least six months,
• 3) being clinically stable (i.e., no recent AIDS-defining opportunistic infections, a CD4+ T-cell count ≥ 200 cells·mm-3, and asymptomatic),
• 4) owning a smartphone with text message capabilities, and
• 5) willing to receive four or more text messages per week.

Exclusion Criteria:

• 1) having a diabetes mellitus diagnosis
• 2) requiring the use of an assistive device for walking as it will impair physical activity,
• 3) participating in any sport or planned exercise program on more than two days per week
• 4) having any signs or symptoms of CVD or any known uncontrolled cardiovascular, pulmonary or neuromuscular disease that may preclude exercise participation,
• 5) severe arthritis, hip or knee fracture or spinal surgery in the past 6 months
• 6) having any contraindications to exercise as identified by the American College of Sports Medicine