Altered ventilatory responses to exercise testing in young adult men with obstructive steep apnea

Background: Obstructive steep apnea (OSA) is a disorder characterized by repetitive obstructions of the upper airway. Individuals with OSA experience intermittent hypoxia, hypercapnia, and arousals during sleep, resutting in increased sympathetic activation. Chemoreflex activation, arising from the resuttant osciLtatory disturbances in btood gases from OSA, exerts control over ventilation, and may induce increases in sympathetic vasoconstriction, contributing to increased long-term risks for hypertension (HTN) and cardiovascular disease (CVD). Methods: To evatuate whether OSA eticits exaggerated ventilatory responses to exercise in young men, 14 overweight men with OSA and 16 overweight men without OSA performed maximal. ramping cycle ergometer exercise tests. Oxygen consumption (VO2), ventilation, (VE), ventilatory equivatents for oxygen (VE/V02) and carbon dioxide (VE/VC02), and VE/VC02 slope were measured. Results: The VC2. response to exercise did not differ between groups. The VE, VE/VCO2, VE/V02 were higher (p < 0.05, 0.002, and p < 0.02, respectivety) in the OSA group across atl. workloads. The VE/VC02 slope was greater in the OSA group (p < 0.05). The VE/VC02 slope and AHI were significantly correlated (r = 0.56, p < 0.03). Thus, young, overweight men with OSA exhibit increased ventilatory responses to exercise when compared to overweight controls. This may reflect alterations in chemoreflex sensitivity, and contribute to increased sympathetic drive and HTN risk. (C) 2009 Elsevier Ltd. All rights reserved.