Abstract
Abstract
Introduction
Autonomic dysregulation associated with obstructive sleep apnea (OSA) may limit cardiopulmonary responses to exercise, which in turn may impair functional aerobic capacity (FAC) and physical performance. We aimed to characterize functional aerobic capacity in OSA patients compared with non-OSA (NO) adults, and examine the relationship between OSA severity (based on AHI) and FAC.
Methods
26 adults (OSA: n=13,47.53 ± 9.6 years, BMI= 29.3 ± 4.8 kg/m2; NO: n=13, 40.46 ± 8.8 years, BMI=23.8 ± 3.3 kg/m2) completed a maximal exercise test, repeated bouts of a constant work rate (CWR) treadmill test at 85% of anaerobic threshold (AT), and a 10-minute walk test (10MWT). All testing was completed over 2 days, with a minimum of 48 hours between test days. Physiological indices used to determine FAC were VO2MAX, VO2-at-AT and walking economy during CWR. Walking performance was determined by distance walked, speed and energy expenditure (EC) during 10MWT. Data were analyzed using ANCOVA, Pearson’s correlation, linear regression, and Omega-squared.
Results
There were significant differences between OSA and non-OSA subjects in VO2MAX (29.69 ± 5.6 mL/kg/min vs. 37.49 ± 6.5 mL/kg/min, p=0.03), VO2-at-AT (19.12 ± 4.79 mL/kg/min vs. 25.9 ± 5 mL/kg/min, p=0.03) and walking economy during CWR (12.20 ± 5.0 vs.18.40 ± 6.5 mL/kg/min, p=0.05). The 10MWT speed, distance and energy expenditure were significantly lower in OSA group (all p<0.0001). Furthermore, VO2-at-AT positively correlated with walking economy (r=0.92, p<0.0001) and 10MWT distance (r=0.50, p=0.012,). AHI score negatively correlated with 10MWT distance (r=-0.71, p<0.0001), VO2MAX (r=-0.47, p=0.01) and VO2-at-AT (r=-0.52, p=0.006). Apnea-hypopnea index (AHI≥ 30) significantly related to VO2-at-AT in OSA patients (R2=0.45, p=0.02).
Conclusion
The findings of this study suggest that patients with OSA have reduced functional aerobic capacity. The relationship between OSA severity and FAC implies that individuals with more severe OSA experience greater impairment in functional performance.
Support (If Any)
N/A.