Diet associated with exercise improves baroreflex control of sympathetic nerve activity in metabolic syndrome and sleep apnea patients

Abstract

PurposeWe tested the hypothesis that (i) diet associated with exercise would improve arterial baroreflex (ABR) control in metabolic syndrome (MetS) patients with and without obstructive sleep apnea (OSA) and (ii) the effects of this intervention would be more pronounced in patients with OSA.MethodsForty-six MetS patients without (noOSA) and with OSA (apnea-hypopnea index, AHI >15events/h) were allocated to no treatment (control, C) or hypocaloric diet (-500kcal/day) associated with exercise (40min, bicycle exercise, 3 times/week) for 4months (treatment, T), resulting in four groups: noOSA-C (n=10), OSA-C (n=12), noOSA-T (n=13), and OSA-T (n=11). Muscle sympathetic nerve activity (MSNA), beat-to-beat BP, and spontaneous arterial baroreflex function of MSNA (ABR(MSNA), gain and time delay) were assessed at study entry and end.ResultsNo significant changes occurred in C groups. In contrast, treatment in both patients with and without OSA led to a significant decrease in weight (P<0.05) and the number of MetS factors (P=0.03). AHI declined only in the OSA-T group (315 to 17 +/- 4events/h, P<0.05). Systolic BP decreased in both treatment groups, and diastolic BP decreased significantly only in the noOSA-T group. Treatment decreased MSNA in both groups. Compared with baseline, ABR(MSNA) gain increased in both OSA-T (13 +/- 1 vs. 24 +/- 2a.u./mmHg, P=0.01) and noOSA-T (27 +/- 3 vs. 37 +/- 3a.u./mmHg, P=0.03) groups. The time delay of ABR(MSNA) was reduced only in the OSA-T group (4.1 +/- 0.2s vs. 2.8 +/- 0.3s, P=0.04).Conclusionsp id=ParDiet associated with exercise improves baroreflex control of sympathetic nerve activity and MetS components in patients with MetS regardless of OSA.