title: Core temperature influences on the relationship between exercise-induced leukocytosis and cortisol or TNF-alpha.
abstract: BACKGROUND
  The extent to which exercise in the heat modifies leukocytosis and the relationship between the leukocytosis and tumor necrosis factor-alpha (TNF-alpha) or cortisol is not well understood. Thus, this study attempted to determine the combined effect of exercise and differing elevations in core temperature on exercise-induced leukocytosis and to examine associations between any leukocytosis and cortisol orTNF-alpha.
  
  
  METHODS
  Eight male subjects completed two 40-min trials while immersed in 25 and 38.5 degrees C water. Leukocytes, TNF-alpha, and cortisol were determined at baseline, immediately post-, and 2 h post-exercise.
  
  
  RESULTS
  Both trials resulted in significant 13-33% increases in total leukocytes, mostly driven by a 24-30% increase in neutrophils. A significant relationship was found between the change in core temperature (T(re)) during exercise and the increase in total leukocytes (r = 0.561). Similarly, the change in T(re) was related to the change in cortisol (r = 0.557) and TNF-alpha (r = 0.483). Yet the exercise-induced change in cortisol was not significantly correlated to any changes in leukocytes. There was a trend for the relationships between the exercise-induced change in TNF-alpha and the changes in total leukocytes (r = 0.491) and neutrophils (r = 0.479).
  
  
  CONCLUSIONS
  These results suggest that although neither cortisol nor TNF-alpha are strong predictors of the leukocyte response during exercise or recovery, each factor may be one of many potential modifiers of the total leukocyte response.
authors.affiliation: Applied Physiology Laboratory, Department of Exercise and Sport Science, CB# 8700, Fetzer Gym, University of North Carolina, Chapel Hill, NC 27599-9700, USA.
authors.forename: Erica S
authors.initials: ES
authors.lastname: Cooper
authors.forename: Mark P
authors.initials: MP
authors.lastname: Berry
authors.forename: Robert G
authors.initials: RG
authors.lastname: McMurray
authors.forename: Peter A
authors.initials: PA
authors.lastname: Hosick
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Hackney
mesh_terms: D000293:Adolescent; D000328:Adult; D001831:Body Temperature / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006358:Hot Temperature; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007101:Immersion; D007964:Leukocytosis; D008297:Male; D014409:Tumor Necrosis Factor-alpha / Q000097:blood*
chemical_list: D014409:Tumor Necrosis Factor-alpha; D006854:Hydrocortisone