title: Maximal fat oxidation, but not aerobic capacity, is affected by oral contraceptive use in young healthy women.
abstract: OBJECTIVE
  Synthetic ovarian hormones contained in oral contraceptives (OC) may alter the aerobic capacity and lipid metabolism in oral contraceptive users (OC+) compared with non-users (OC-). The aim of this study was thus to investigate the differences between OC- and OC+ (1) in cardiorespiratory parameters at the anaerobic threshold (AT) and at the maximal aerobic capacity and (2) in the exercise intensity (Lipoxmax) at which lipid oxidation rate is maximal (MLOR).
  
  
  METHODS
  Twenty-one healthy untrained women (22.0 ± 0.6 years old) who took OC (OC+; low-dose monophasic OC, n = 11) or not (OC-; n = 10) performed two experimental exercise sessions. In the first one, cardiorespiratory parameters at the AT and at the maximal aerobic capacity were assessed during a maximal incremental exercise session. In the second one, Lipoxmax and MLOR were measured during a submaximal incremental exercise session.
  
  
  RESULTS
  No significant difference was observed in cardiorespiratory parameters at the AT and at the maximal aerobic capacity between OC+ and OC- women. OC+ women showed higher MLOR (7.6 ± 1.9 vs 4.6 ± 1.0 mg min(-1) kg FFM(-1); p < 0.01) that was elicited by higher Lipoxmax (45.2 ± 5.2 vs 36.2 ± 4.1 % of VO2max; p < 0.001) compared to OC- women.
  
  
  CONCLUSIONS
  OC+ and OC- women did not differ in cardiorespiratory parameters at the AT and at the maximal aerobic capacity. However, OC+ women show higher MLOR and Lipoxmax compared with OC- women. The hormonal status appears to be an important MLOR and Lipoxmax determinant in untrained women.
authors.affiliation: Culture Sport Health Society Laboratory, EA 4660, and Exercise Performance, Health, Innovation Platform, Franche-Comte University, 25000, Besançon, France, isaccolaurie@hotmail.com.
authors.forename: Laurie
authors.initials: L
authors.lastname: Isacco
authors.forename: David
authors.initials: D
authors.lastname: Thivel
authors.forename: Bruno
authors.initials: B
authors.lastname: Pereira
authors.forename: Martine
authors.initials: M
authors.lastname: Duclos
authors.forename: Nathalie
authors.initials: N
authors.lastname: Boisseau
mesh_terms: D015308:Anaerobic Threshold; D001823:Body Composition / Q000502:physiology; D003276:Contraceptives, Oral / Q000494:pharmacology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D050356:Lipid Metabolism / Q000187:drug effects*; D010084:Oxidation-Reduction / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects*; D055815:Young Adult
chemical_list: D003276:Contraceptives, Oral