title: Mild dehydration does not reduce postexercise appetite or energy intake.
abstract: OBJECTIVE
  It has now been established that exercise performed under various environmental conditions may affect acute energy intake and appetite-related hormones. The exact mechanism linking acute energy intake and exercise remains unknown, although indirect evidence suggests a possible role for hydration status. Therefore, the purpose of this study was to investigate the interaction of exercise and hydration status on subsequent energy intake and appetite-related hormones.
  
  
  METHODS
  In a randomized, counterbalanced design, 10 physically active males completed three experimental trials in a fasted state: exercise when hydrated (0%-1% of body mass), exercise when dehydrated (-1% to -2% of body mass), and a hydrated resting control. Exercise consisted of treadmill running for 45 min at 70% VO2peak. Participants were then given access to a buffet-style breakfast from which they could consume ad libitum. Blood was sampled regularly during trials for appetite-related hormones.
  
  
  RESULTS
  There were no significant differences in total energy intake between trials (P = 0.491); however, relative energy intake was significantly higher in the control (4839 ± 415 kJ, P < 0.001) compared to hydrated (1749 ± 403 kJ) and dehydrated exercise (1656 ± 413 kJ) conditions. Exercise performed in a dehydrated state resulted in significantly lower concentrations of ghrelin compared with control (P = 0.045) and hydrated exercise conditions (P = 0.014).
  
  
  CONCLUSIONS
  Exercise significantly decreased relative energy intake compared with resting control; however, energy intake (relative and total) was no different between the exercise conditions (dehydrated vs hydrated). Despite similar energy intake between trials, exercise in a dehydrated state resulted in a significantly lower concentration of ghrelin, a hormone responsible for stimulating appetite.
authors.affiliation: School of Sport Science, Exercise and Health, The University of Western Australia, Perth, Australia.
authors.forename: Peta J
authors.initials: PJ
authors.lastname: Kelly
authors.forename: Kym J
authors.initials: KJ
authors.lastname: Guelfi
authors.forename: Karen E
authors.initials: KE
authors.lastname: Wallman
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Fairchild
mesh_terms: D000704:Analysis of Variance; D001066:Appetite / Q000502:physiology*; D001786:Blood Glucose / Q000378:metabolism; D003681:Dehydration / Q000503:physiopathology*; D002149:Energy Intake / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005215:Fasting; D054439:Ghrelin / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism; D020738:Leptin / Q000378:metabolism; D008297:Male; D010191:Pancreatic Polypeptide / Q000378:metabolism; D019894:Peptide YY / Q000378:metabolism; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D054439:Ghrelin; D007328:Insulin; D020738:Leptin; D019894:Peptide YY; D010191:Pancreatic Polypeptide