title: The relationship between serum and salivary cortisol levels in response to different intensities of exercise.
abstract: OBJECTIVE
  The effect of exercise intensity on the tracking of serum and salivary cortisol responses was examined in 12 endurance-trained males (maximal oxygen uptake [VO2max] = 58.2 ± 6.4 mL/kg/min).
  
  
  METHODS
  Subjects rested for 30 min (control) and exercised on a cycle ergometer for 30 min at 40% (low), 60% (moderate), and 80% (high intensity) of VO2max on separate days. Serum and saliva samples were collected pretrial, immediately posttrial, and 30 min into the recovery period from each trial.
  
  
  RESULTS
  Cortisol responses increased significantly for both serum (40.4%; P = .001) and saliva (170.6%; P = .007) only in response to high-intensity exercise. Peak saliva cortisol occurred at 30 min of recovery, whereas peak serum was at the immediate posttrial sampling time point. The association between serum and saliva cortisol across all trials was examined using concordance correlation (Rc) analysis, which accounts for repeated measures. The overall correlation between serum and saliva cortisol levels in all matched samples was significant (Rc = 0.728; P = .001). The scatter plot revealed that salivary cortisol responses tracked closely to those of serum at lower concentrations, but not as well at higher concentrations.
  
  
  CONCLUSIONS
  Findings suggest salivary measurements of cortisol closely mirror those in the serum and that peak salivary concentrations do not occur until at least 30 min into the recovery from intense exercise.
authors.affiliation: Department of Exercise & Sport Science, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Mitch D
authors.initials: MD
authors.lastname: VanBruggen
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Hackney
authors.forename: Robert G
authors.initials: RG
authors.lastname: McMurray
authors.forename: Kristin S
authors.initials: KS
authors.lastname: Ondrak
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001642:Bicycling; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D015444:Exercise; D005080:Exercise Test; D006801:Humans; D006854:Hydrocortisone / Q000097:blood / Q000378:metabolism*; D008297:Male; D009657:North Carolina; D010101:Oxygen Consumption; D010807:Physical Endurance; D020127:Recovery of Function; D012463:Saliva / Q000378:metabolism*; D013997:Time Factors; D015854:Up-Regulation; D055815:Young Adult
chemical_list: D015415:Biomarkers; D006854:Hydrocortisone