Document Type



Exercise Physiology

Publication Date



Background: Autonomic dysregulation associated with obstructive sleep apnea (OSA) may limit cardiopulmonaryresponses to exercise, which, in turn, may impair functional aerobic capacity (FAC) and walking economy. Weaimed to characterize walking economy and FAC in OSA patients compared with healthy adults (non-OSA) andexamine their relationship with OSA severity (apnea-hypopnea index [AHI]).

Methods: A total of 26 adults (OSA,n= 13; non-OSA,n= 13) participated in this cross-sectional study. In this study,the participants with OSA were between the ages of 25 and 60 years, with a body mass index of 25 kg/m2to 39 kg/m2, and who had undergone a recent third-party sleep study with an AHI of 5 or greater. Participants completed amaximal integrated cardiopulmonary exercise test, three separate exercise bouts of constant work rate (CWR)treadmill test at 85% of anaerobic threshold (AT), and a 10-min walk test (10MWT). Multiple linear regressionanalysis corrected for weight, age, and BMI were performed to examine the associations.

Results:There were significant differences between OSA and non-OSA participants in VO2peak(29.7 ± 5.6 mL/kg/minvs. 37.5 ± 6.5 mL/kg/min,p= 0.03) and Net VO2during CWR (12.7 ± 5 vs.19 ± 6 mL/kg/min,p= 0.02). The 10MWTspeed and distance were significantly lower in the OSA group (allp< 0.001). The energy cost of walking duringsubmaximal exercise and 10-min walk test was higher among patients with OSA (allp< 0.001). The AHI scores wereassociated with 10MWT distance (R2= 0.85,p< 0.001), energy cost of walking (R2= 87,p< 0.001), and VO2atanaerobic threshold (R2= 0.92,p< 0.001).

Conclusions:The findings of this study show that patients with OSA have reduced FAC and a higher energy cost ofwalking. AHI explained 87% of variance in the energy cost of walking during the 10MWT. The results suggest that individuals with more severe obstructive sleep apnea experience greater impairment in functional performance.