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Core temperature influences on the relationship between exercise-induced leukocytosis and cortisol or TNF-alpha
Erica S Cooper1, Mark P Berry, Robert G McMurray
1Applied Physiology Laboratory, Department of Exercise and Sport Science, CB# 8700, Fetzer Gym, University of North Carolina, Chapel Hill, NC 27599-9700, USA.
Introduction:
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).
Discussion:
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.
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