BACKGROUND: Obstructive sleep apnea (OSA) is a disorder characterized by repetitive obstructions of the upper airway. Individuals with OSA experience intermittent hypoxia, hypercapnia, and arousals during sleep, resulting in increased sympathetic activation. Chemoreflex activation, arising from the resultant oscillatory disturbances in blood 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 evaluate whether OSA elicits 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 (VO(2)), ventilation, (V(E)), ventilatory equivalents for oxygen (V(E)/VO(2)) and carbon dioxide (V(E)/VCO(2)), and V(E)/VCO(2) slope were measured. RESULTS: The VO(2) response to exercise did not differ between groups. The V(E), V(E)/VCO(2), V(E)/VO(2) were higher (p< 0.05, 0.002, and p<0.02, respectively) in the OSA group across all workloads. The V(E)/VCO(2) slope was greater in the OSA group (p<0.05). The V(E)/VCO(2) 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.
BACKGROUND:Obstructive sleep apnea (OSA) is a disorder characterized by repetitive obstructions of the upper airway. Individuals with OSA experience intermittent hypoxia, hypercapnia, and arousals during sleep, resulting in increased sympathetic activation. Chemoreflex activation, arising from the resultant oscillatory disturbances in blood 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 evaluate whether OSA elicits 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 (VO(2)), ventilation, (V(E)), ventilatory equivalents for oxygen (V(E)/VO(2)) and carbon dioxide (V(E)/VCO(2)), and V(E)/VCO(2) slope were measured. RESULTS: The VO(2) response to exercise did not differ between groups. The V(E), V(E)/VCO(2), V(E)/VO(2) were higher (p< 0.05, 0.002, and p<0.02, respectively) in the OSA group across all workloads. The V(E)/VCO(2) slope was greater in the OSA group (p<0.05). The V(E)/VCO(2) 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.
Authors: Bruno Teixeira Barbosa; Amilton da Cruz Santos; Murillo Frazão; Tulio Rocha Petrucci; Gabriel Grizzo Cucato; Adriana Oliveira Sarmento; Eduardo D S Freitas; Anna Myrna Jaguaribe de Lima; Maria do Socorro Brasileiro-Santos Journal: Sleep Breath Date: 2017-08-24 Impact factor: 2.816
Authors: Christopher E Kline; E Patrick Crowley; Gary B Ewing; James B Burch; Steven N Blair; J Larry Durstine; J Mark Davis; Shawn D Youngstedt Journal: Int J Cardiol Date: 2012-05-08 Impact factor: 4.164