title: 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 (D+ET) would improve peripheral and central chemoreflex sensitivity in patients with MetS and OSA.
  
  
  METHODS
  Patients were assigned to: (1) D+ET (n = 16) and (2) no intervention control (C, n = 8). Minute ventilation (VE, pre-calibrated pneumotachograph) and muscle sympathetic nerve activity (MSNA, microneurography) were evaluated during peripheral chemoreflex sensitivity by inhalation of 10% O2 and 90% N2 with CO2 titrated and central chemoreflex by 7% CO2 and 93% O2 for 3 min at study entry and after 4 months.
  
  
  RESULTS
  Peak VO2 was increased by D+ET; body weight, waist circumference, glucose levels, systolic/diastolic blood pressure, and apnea-hypopnea index (AHI) (34 ± 5.1 vs. 18 ± 3.2 events/h, P = 0.04) were reduced by D+ET. MSNA was reduced by D+ET at rest and in response to hypoxia (8.6 ± 1.2 vs. 5.4 ± 0.6 bursts/min, P = 0.02), and VE in response to hypercapnia (14.8 ± 3.9 vs. 9.1 ± 1.2 l/min, P = 0.02). No changes were found in the C group. A positive correlation was found between AHI and MSNA absolute changes (R = 0.51, P = 0.01) and body weight and AHI absolute changes (R = 0.69, P < 0.001).
  
  
  CONCLUSIONS
  Sympathetic peripheral and ventilatory central chemoreflex sensitivity was improved by D+ET in MetS+OSA patients, which may be associated with improvement in sleep pattern.
authors.affiliation: Cardiovascular Rehabilitation and Exercise Physiology Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Cristiane
authors.initials: C
authors.lastname: Maki-Nunes
authors.affiliation: Cardiovascular Rehabilitation and Exercise Physiology Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Edgar
authors.initials: E
authors.lastname: Toschi-Dias
authors.affiliation: Cardiovascular Rehabilitation and Exercise Physiology Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Felipe X
authors.initials: FX
authors.lastname: Cepeda
authors.affiliation: Cardiovascular Rehabilitation and Exercise Physiology Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.|Biodinâmica, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil.
authors.forename: Maria Urbana P B
authors.initials: MU
authors.lastname: Rondon
authors.affiliation: Cardiovascular Rehabilitation and Exercise Physiology Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Maria-Janieire N N
authors.initials: MJ
authors.lastname: Alves
authors.affiliation: Cardiovascular Rehabilitation and Exercise Physiology Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Raffael F
authors.initials: RF
authors.lastname: Fraga
authors.affiliation: Cardiovascular Rehabilitation and Exercise Physiology Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Ana Maria F W
authors.initials: AM
authors.lastname: Braga
authors.affiliation: Cardiovascular Rehabilitation and Exercise Physiology Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Adriana M
authors.initials: AM
authors.lastname: Aguilar
authors.affiliation: Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Aline C
authors.initials: AC
authors.lastname: Amaro
authors.affiliation: Hypertension Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Luciano F
authors.initials: LF
authors.lastname: Drager
authors.affiliation: Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Geraldo
authors.initials: G
authors.lastname: Lorenzi-Filho
authors.affiliation: Cardiovascular Rehabilitation and Exercise Physiology Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.|Biodinâmica, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil.
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Negrão
authors.affiliation: Cardiovascular Rehabilitation and Exercise Physiology Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.|Programa da Pós-Graduação em Medicina, Universidade Nove De Julho (UNINOVE), São Paulo, Brazil.
authors.forename: Ivani C
authors.initials: IC
authors.lastname: Trombetta
mesh_terms: D000328:Adult; D002245:Carbon Dioxide / Q000378:metabolism; D002628:Chemoreceptor Cells / Q000378:metabolism; D004038:Diet, Reducing; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications*; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000628:therapy*; D020181:Sleep Apnea, Obstructive / Q000150:complications*; D013564:Sympathetic Nervous System / Q000378:metabolism / Q000503:physiopathology*; D016896:Treatment Outcome
chemical_list: D002245:Carbon Dioxide