Abstract 12647: Effects of Diet and Exercise Training on Sympathetic Hyperactivation and Baroreflex Sensitivity in Patients with Metabolic Syndrome and Obstructive Sleep Apnea
Purpose: Previous studies demonstrated that hypocaloric diet and exercise training (D+ET) increase baroreflex sensitivity (BRS) and decrease muscle sympathetic nerve activity (MSNA) in metabolic syndrome patients (MetSyn). However, the effects of D+ET on these autonomic regulations in patients with both MetSyn and obstructive sleep apnea (OSA) remain unknown. We tested the hypotheses that the effects of D+ET on BRS and MSNA would be more pronounced in patients with MetSyn and OSA than in patients with MetSyn without OSA.
Methods: Thirty never-treated patients with MetSyn (ATP III) were allocated in two groups: 1) with OSA (MetSyn+OSA, n=15); and 2) without OSA (MetSyn-OSA, n=15). Both groups were submitted to a supervised D+ET (-500 kcal/day, 60 min 3 times per week) program for 4-months. OSA was deferred as the apnea-hypopnea index≥15 events/hour (polysomnography). MSNA was recorded directly from the peroneal nerve (microneurography). Blood pressure (BP) was recorded on a beat-to-beat basis and heart rate (HR) by ECG. The BRS was assessed by spontaneous fluctuations of BP and HR over 10 min period.
Results: After D+ET, body weight, waist circumference, systolic and diastolic BP were significantly reduced in both groups. D+ET significantly decreased MSNA in MetSyn+OSA and MetSyn-OSA patients (33±1 to 26±1 and 28±1 to 24±1 bursts/min, P<0.001, respectively). Additionally, in both MetSyn+OSA and MetSyn-OSA patients, D+ET significantly augmented BRS during increases (5.4±0.1 to 9.3±0.6 and 11.9±1.3 to 15.3±1.4 ms/mmHg, P<0.001, respectively) and decreases in BP (6.0±0.1 to 9.2±0.7 and 12.1±1.2 to 15.0±1.4 ms/mmHg, P<0.001, respectively).
Conclusion: D+ET improves BRS and reduces sympathetic nerve activity in patients with MetSyn regardless of OSA. These findings demonstrate that the association of hypocaloric diet and exercise training should be strongly recommended to the treatment of patients with MetSyn, including those suffering of sleep disorder.
- © 2011 by American Heart Association, Inc.