title: The relationship between aerobic fitness level and metabolic profiles in healthy adults.
abstract: METHODS
  Application of metabolomics to nutrition and health research is increasing and while much effort has been invested in understanding factors that influence the metabolomic profile there is relatively little known about the impact of fitness level. This study aimed to examine the relationship between fitness level, substrate oxidation rates, and the metabolic profile.
  
  
  RESULTS
  Two hundred and fourteen healthy adults (18-60 years) were recruited and 65 subjects were selected based on their estimated maximal oxygen consumption levels. Metabolomic analysis was performed. The subjects were split into fitness groups according to their maximal oxygen consumption levels (mL/kg/min) and analysis revealed significant differences in normalized fat and carbohydrate oxidation levels between the groups. Urinary metabolomic analysis revealed significantly different profiles in the groups with 15 amino acids significantly higher in the low fitness groups. Effects of fitness level in the plasma metabolic profiles were also demonstrated.
  
  
  CONCLUSIONS
  This study demonstrates a relationship between fitness level and the amino acid profile. Moreover, the metabolite changes show that a reduced excretion of amino acids in adults is associated with increased fitness levels and an increased fat oxidation rate during exercise. Interestingly, higher levels of branched chain amino acids were associated with lower fitness levels and higher insulin resistance.
authors.affiliation: UCD Institute of Food and Health, University College Dublin, Belfield, Dublin, Ireland.
authors.forename: Ciara
authors.initials: C
authors.lastname: Morris
authors.forename: Colm O
authors.initials: CO
authors.lastname: Grada
authors.forename: Miriam
authors.initials: M
authors.lastname: Ryan
authors.forename: Helen M
authors.initials: HM
authors.lastname: Roche
authors.forename: Giuseppe
authors.initials: G
authors.lastname: De Vito
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Gibney
authors.forename: Eileen R
authors.initials: ER
authors.lastname: Gibney
authors.forename: Lorraine
authors.initials: L
authors.lastname: Brennan
mesh_terms: D000293:Adolescent; D000328:Adult; D000597:Amino Acids, Branched-Chain / Q000097:blood / Q000652:urine; D001823:Body Composition; D015331:Cohort Studies; D004734:Energy Metabolism; D015444:Exercise; D005215:Fasting; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D055442:Metabolome / Q000502:physiology*; D055432:Metabolomics; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D010809:Physical Fitness; D055815:Young Adult
chemical_list: D000597:Amino Acids, Branched-Chain
keywords: Branched chain amino acids; Exercise; Fitness; Insulin resistance; Metabolomics