Attenuated heart rate recovery following exercise testing in overweight young men with untreated obstructive sleep apnea

Study Objective: To evaluate whether cardiovascular responses to maximal exercise testing and recovery are altered with obstructive sleep apnea (OSA) in overweight young adult men. Design: Three sedentary subject groups were recruited: Overweight with OSA (OSA), overweight without OSA (No-OSA), and normal weight without OSA (Control). Presence of OSA was screened via portable diagnostic device. Body composition was measured with dual-energy X-ray absorptiometry. Subjects performed maximal ramping exercise testing (RXT) on a cycle ergometer with 5 minutes of active recovery. Exercise measurements included heart rate (HR), blood pressure (BP), respiratory exchange ratio (RER), and oxygen consumption (VO₂). Recovery HR was converted to a HR difference (HR_diff)calculation(HR_peak-HR _{each minute recovery}), and BP was converted to a recovery ratio for each minute. Setting: The study was carried out on the campus of Virginia Tech, Department of Human Nutrition, Foods, and Exercise, Blacksburg, Virginia. Participants: 14 OSA, 16 No-OSA, and 14 Control volunteers. Intervention: N/A Measurements and Results: In OSA subjects, HR recovery was significantly attenuated compared to the No-OSA and Control groups throughout recovery (P = 0.009). No differences were noted in the HR or BP response to exercise in any group. The VO₂, adjusted for fat-free soft tissue mass, did not differ between groups. Conclusions: We found that OSA elicits alterations in the cardiovascular response post exercise, reflected by an attenuated HR recovery. This may indicate an imbalance in the autonomic regulation of HR. Exercise tests may provide utility in risk stratification for those at risk for OSA.