Metabolic efficiency during exercise in patients with overlap of obstructive sleep apnea in metabolic syndrome

Metabolic syndrome patients (MetS) have increased cardiovascular risk in the presence of obstructive sleep apnea (OSA). Besides decreased peak oxygen consumption (VO2peak), the impairment on metabolic efficiency by linear regression (slope) of increases in VO2 and increases in workload (ΔVO2/ΔW) during submaximal exercise test can be used as a marker of worst prognosis. So, we tested the hypotheses that ΔVO2/ΔW is decreased in MetS patients and the association of MetS and OSA causes further impairment on VO2peak and ΔVO2/ΔW. Seventy eight MetS sedentary patients (ATP-III) without the use of drugs were divided into: MetS+OSA (n=31, 49±2 yrs) and MetS-OSA (n=30, 46±1 yrs). A control group (C; n=17, 48±2 yrs) was also studied. OSA was determined by apnea/hypopnea index (AHI>15events/h-polysomnography). The slope ΔVO2/ΔW was determined from the 1st min up to respiratory compensation point during cardiopulmonary exercise testing.The MetS+OSA and MetS-OSA are similar and had lower ΔVO2/ΔW (0.12±0.01, 0.13±0.01 ...