CPAP Does Not Modify Exercise-Derived Autonomic Responses in Nonsleepy Patients with Coronary Artery Disease and Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is associated with autonomic dysfunction and increased cardiovascular risk, but the effects of continuous positive airway pressure (CPAP) on exercise-derived autonomic responses in patients with coronary artery disease (CAD) remain unclear. This study included nonsleepy patients (Epworth Sleepiness Scale score <10) with CAD and OSA (apnea–hypopnea index ≥15 events/h) enrolled in the RICCADSA randomized controlled trial. Of 244 patients randomized at baseline, 204 (CPAP n=100; no-CPAP n=104) completed bicycle ergometer exercise testing at both 3 and 12 months and were included. The primary outcome was the change in 1-minute heart rate recovery (HRR1) from 3 to 12 months; secondary outcomes included changes in 4-minute heart rate recovery (HRR4), chronotropic response, and post-exercise recovery time. Longitudinal changes were analyzed using linear mixed-effects models adjusted for sex, body mass index (BMI), diabetes, and β-blocker use. HRR1 remained stable from 3 to 12 months in both groups (approximately 22–23 bpm), with no CPAP or time×treatment effects. HRR4 showed no differential change, remaining around 46–47 bpm. Chronotropic response was unchanged (chronotropic index approximately 0.74–0.76 in both groups). Exercise workload and peak heart rate remained stable over time and did not differ between groups. Post-exercise recovery time shortened significantly in the overall cohort (by approximately 0.3 minutes from 3 to 12 months) but was not CPAP-specific. Higher BMI and β-blocker use were independently associated with impaired late HRR and chronotropic response. In nonsleepy patients with CAD and OSA, CPAP does not modify exercise-derived autonomic or chronotropic responses, underscoring the need for complementary strategies targeting metabolic burden and cardiovascular conditioning. • CPAP did not alter exercise-derived autonomic responses in nonsleepy patients with coronary artery disease and obstructive sleep apnea. • Heart rate recovery and chronotropic response showed no differential change between CPAP and no-CPAP groups over time. • Higher body mass index and β-blocker use were independently associated with impaired autonomic and chronotropic responses. • Exercise-derived autonomic metrics should not be considered surrogate markers of CPAP treatment efficacy.