title: Adults with initial metabolic syndrome have altered muscle deoxygenation during incremental exercise.
abstract: Reduced aerobic power is independently associated with metabolic syndrome (MetS) incidence and prevalence in adults. This study investigated whether muscle deoxygenation (proxy of microvascular O2extraction) during incremental exercise is altered in MetS and associated with reduced oxygen consumption ( V˙O2peak).
  
  
  
  Twelve men with initial MetS (no overt diseases and medication-naive; mean ± SD, age 38 ± 7 years) and 12 healthy controls (HCs) (34 ± 7 years) completed an incremental cycling test to exhaustion, in which pulmonary ventilation and gas exchange (metabolic analyzer), as well as vastus lateralis deoxygenation (near infrared spectroscopy), were measured.
  
  
  
  Subjects with MetS, in contrast to HCs, showed lower V˙O2peaknormalized to total lean mass, similar V˙O2response to exercise, and earlier break point (BP) in muscle deoxygenation. Consequently, deoxygenation slope from BP to peak exercise was greater. Furthermore, absolute V˙O2peakwas positively associated with BP in correlations adjusted for total lean mass.
  
  
  
  MetS, without overt diseases, altered kinetics of muscle deoxygenation during incremental exercise, particularly at high-intensity exercise. Therefore, the balance between utilization and delivery of O2within skeletal muscle is impaired early in MetS natural history, which may contribute to the reduction in aerobic power.
authors.affiliation: Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.
authors.forename: Alessandro da Costa
authors.initials: AD
authors.lastname: Machado
authors.affiliation: Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.
authors.forename: Thales Coelho
authors.initials: TC
authors.lastname: Barbosa
authors.affiliation: Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.
authors.forename: Allan Robson
authors.initials: AR
authors.lastname: Kluser Sales
authors.affiliation: Department of Electronics and Computing, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Marcio Nogueira
authors.initials: MN
authors.lastname: de Souza
authors.affiliation: Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.
authors.forename: Antonio Claudio Lucas
authors.initials: AC
authors.lastname: da Nóbrega
authors.affiliation: Department of Physiology, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Bruno Moreira
authors.identifier: 0000-0003-0473-3706
authors.initials: BM
authors.lastname: Silva
mesh_terms: D000328:Adult; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000000981:diagnostic imaging / Q000378:metabolism*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D011659:Pulmonary Gas Exchange; D019265:Spectroscopy, Near-Infrared