Abstract 14: Impact of High Intensity Interval Training versus Continuous Moderate Intensity Exercise on Cardiorespiratory Fitness for People with HIV: Results from the HEALTH Multicenter Randomized Clinical Trial

Abstract

Objectives: HIV is associated with reduced cardiorespiratory fitness (CRF), a strong predictor of future cardiovascular events and mortality. Supervised exercise training programs improve CRF, but the ideal exercise training intensity is unknown among PWH. We hypothesized that high-intensity interval training (HIIT) would result in greater improvements in CRF than continuous moderate-intensity exercise (CME) without increased risk of adverse events among older sedentary adults with HIV. Methods: We conducted a multicenter randomized clinical trial of people ages 50 years and older with treated, virally-suppressed HIV, self-reported fatigue, and sedentary lifestyle. Participants were randomized 1:1 to 16 weeks of supervised HIIT or CME. Cardiopulmonary exercise testing (CPET) using a treadmill graded exercise protocol was performed prior to randomization and at 16 weeks to assess CRF, measured as peak oxygen consumption (VO 2 ). CPETs were interpreted blinded to treatment assignment. The trial was preregistered at ClinicalTrials.gov NCT04550676. Results: Among 212 PWH screened, 142 consented, 127 completed baseline CPET, 118 were randomized (110 with adequate quality CPET): 54 to HIIT and 56 to CME. Median age was 56.5 years, 12% female, and 44% were obese (BMI ≥30). At baseline, absolute peak VO 2 was 2.3 L/min and relative to body weight was 25 ml/kg/min (91% predicted peak VO 2 ). In the intention-to-treat analysis adjusted for age, sex, and site, assignment to HIIT was associated with a 0.14 L/min greater increase in absolute peak VO 2 from baseline to 16 weeks compared to CME (95% CI 0.01 to 0.27, p =0.03) and a 1.60 ml/kg/min greater increase in relative peak VO 2 (95% CI 0.23 to 2.97; p =0.023). Results were consistent in unadjusted and per-protocol analyses. Six serious adverse events (SAEs) occurred during the 16-week intervention: 4 unrelated (including 1 death), 2 related (both syncope) in the CME arm; participants were evaluated by cardiology and resumed exercise without further SAEs. There were more nonserious AEs in the HIIT group (40 versus 22 in CME group), mostly mild-moderate musculoskeletal injuries. Conclusions: Among older sedentary people with HIV, HIIT is associated with a greater improvement in CRF assessed with CPET compared to CME, without a greater risk of serious adverse events. Exercise recommendations for aging people with HIV should consider the greater cardiopulmonary benefit of HIIT compared to CME.