Diet and exercise improve chemoreflex sensitivity in patients with metabolic syndrome and obstructive sleep apnea

Abstract

Objective: Chemoreflex hypersensitity was caused by obstructive sleep apnea (OSA) in patients with metabolic syndrome (MetS). This study tested the hypothesis that hypocaloric diet and exercise training (D1ET) would improve peripheral and central chemoreflex sensitivity in patients with MetS and OSA. Methods: Patients were assigned to: (1) D1ET (n 5 16) and (2) no intervention control (C, n 5 8). Minute ventilation (VE, pre-calibrated pneumotachograph) and muscle sympathetic nerve activity (MSNA, microneurography) were evaluated during peripheral chemoreflex sensitivity by inhalation of 10% O 2 and 90% N 2 with CO 2 titrated and central chemoreflex by 7% CO 2 and 93% O 2 for 3 min at study entry and after 4 months. Results: Peak VO 2 was increased by D1ET; body weight, waist circumference, glucose levels, systolic/diastolic blood pressure, and apnea-hypopnea index (AHI) (34 6 5.1 vs. 18 6 3.2 events/h, P 5 0.04) were reduced by D1ET. MSNA was reduced by D1ET at rest and in response to hypoxia (8.6 6 1.2 vs. 5.4 6 0.6 bursts/min, P 5 0.02), and VE in response to hypercapnia (14.8 6 3.9 vs. 9.1 6 1.2 l/min, P 5 0.02). No changes were found in the C group. A positive correlation was found between AHI and MSNA absolute changes (R 5 0.51, P 5 0.01) and body weight and AHI absolute changes (R 5 0.69, P < 0.001). Conclusions: Sympathetic peripheral and ventilatory central chemoreflex sensitivity was improved by D1ET in MetS1OSA patients, which may be associated with improvement in sleep pattern.

Análise Da Efetividade De Estratégia Nutricional Em Mulheres Com Síndrome Metabólica

“…A maioria dos pacientes de ambos os grupos quando iniciaram o tratamento nutricional evidenciou baixo consumo calórico comparado às necessidades nutricionais adequadas a cada faixa etária. Barbieri et al 30 constataram que apesar da ingestão ser reduzida em pacientes obesos, este método não garante a perda de peso, pois os mesmos apresentam gasto energético reduzido, proveniente do sedentarismo 31 .…”

Diet and exercise in obstructive sleep apnea patients with obesity: I'll breathe to that!

“…Interventions aimed at reducing the obesity burden, a major contributor to altered integrative autonomic nervous system reactivity, should ameliorate the underlying chemoreflexes, particularly when combined with potential beneficial effect of exercise on chemoreflexes. In a small, carefully supervised cohort of OSA patients with obesity and the metabolic syndrome receiving the D+E intervention and relatively well‐matched controls, D+E reduced peripheral sympathetic tonic and reactive outflow responses as elicited by isocapnic hypoxia without modifying the putatively mediated central sympathetic responses elicited by hyperoxic hypercapnia . Conversely, no changes occurred with D+E in the ventilatory responses to hypoxia, while reductions in minute ventilatory increases following hypercapnic challenges were detected.…”

“…Conversely, no changes occurred with D+E in the ventilatory responses to hypoxia, while reductions in minute ventilatory increases following hypercapnic challenges were detected. Interestingly, the changes in peripheral sympathetic responses were associated with the changes in respiratory disturbance during sleep, while changes in the latter were strongly correlated with corresponding body weight changes .…”

“…In this issue of the journal, Maki‐Nunes et al tackle this important question, namely the effect of low‐caloric diet and regular exercise (D+E) on one of the putative major drivers of cardiovascular and metabolic dysfunction in OSA, i.e., the integrated chemoreflex network . Interventions aimed at reducing the obesity burden, a major contributor to altered integrative autonomic nervous system reactivity, should ameliorate the underlying chemoreflexes, particularly when combined with potential beneficial effect of exercise on chemoreflexes.…”

“…). Another insight provided by Maki‐Nunes et al is the exquisite sensitivity of the autonomic network gain properties to changes in the frequency and severity of OSA, as illustrated by reduced responses of muscle sympathetic nerve activity during hypoxia. Although the experimental setup does not decipher whether changes in peripheral chemoreceptor sensitivity or changes in central integrative processing underlie these responses , they provide reassurance as to the continued plasticity of the system and attest to the potential improvements after targeted interventions.…”