Chronotropic Incompetence Among People With HIV Improves With Exercise Training in the Exercise for Healthy Aging Study.

Background: People with HIV (PWH) have lower exercise capacity than peers without HIV, which may be explained by chronotropic incompetence, the inability to increase heart rate during exercise.

Methods: The Exercise for Healthy Aging Study included adults aged 50 to 75 years with and without HIV. Participants completed 12 weeks of moderate-intensity exercise, before randomization to moderate or high intensity for 12 additional weeks. We compared adjusted heart rate reserve (AHRR; chronotropic incompetence <80%) on cardiopulmonary exercise testing by HIV serostatus and change from baseline to 12 and 24 weeks using mixed effects models.

Results: Among 32 PWH and 37 controls (median age, 56 years; 7% female), 28% of PWH vs 11% of controls had chronotropic incompetence at baseline (P = .067). AHRR was lower among PWH (91% vs 101%; difference, 10%; 95% CI, 1.9%-18.9%; P = .02). At week 12, AHRR normalized among PWH (+8%; 95% CI, 4%-11%; P < .001) and was sustained at week 24 (+5%; 95% CI, 1%-9%; P = .008) versus no change among controls (95% CI, -4% to 4%; P = .95; interaction P = .004). After 24 weeks of exercise, 15% of PWH and 10% of controls had chronotropic incompetence (P = .70).

Conclusions: Chronotropic incompetence contributes to reduced exercise capacity among PWH and improves with exercise training.