Submitted on July 20, 2007
Accepted on September 27, 2007
Human blood neutrophil responses to prolonged exercise with and without a thermal clamp
Stewart J. Laing1, Anna R. Jackson2, Robert Walters3, Enid Lloyd-Jones3, Martin Whitham4, Norbert Maassen5, and Neil Peter Walsh6*
1 Olympic Medical Institute, Northwick Park Hospital, Harrow , United Kingdom
2 Olympic medical institute, Northwick Park Hospital, London, United Kingdom
3 Haematology, Ysbyty Gwynedd, Bangor, United Kingdom
4 School of Sport, Health and Exercise Sciences, University of Wales, Bangor, Bangor, United Kingdom
5 Sports and Exercise Physiology, Medical School Hannover, Hannover, Germany
6 School of Sport, Health and Exercise Sciences, University of Wales Bangor, Bangor, United Kingdom
* To whom correspondence should be addressed. E-mail: n.walsh{at}bangor.ac.uk.
The purpose was to investigate the effects of prolonged exercise with and without a thermal clamp on neutrophil trafficking, bacterial-stimulated neutrophil degranulation, stress hormones and cytokine responses. Thirteen healthy male volunteers (mean ± SE: age 21 ± 1 y; mass 74.9 ± 2.1 kg; VO2 max 58 ± 1 ml·kg-1·min-1) completed four randomly assigned 2h water immersion trials separated by 7d. Trials were exercise-induced heating (EX-H: water temperature 36°C), exercise with a thermal clamp (EX-C: 24°C), passive heating (PA-H: 38.5°C) and control (CON: 35°C). EX-H and EX-C comprised 2h deep water running at 58% VO2 max. Blood samples were collected at pre, post and 1h post-immersion. Core body temperature was unaltered on CON, clamped on EX-C (-0.02°C) and rose by 2.23°C on EX-H and 2.31°C on PA-H. Exercising with a thermal clamp did not blunt the neutrophilia post-exercise (EX-C post ex: 9.6 ± 1.1 and EX-H post ex: 9.8 ± 1.0 x 109.L-1). Neutrophil degranulation decreased (P<0.01) similarly immediately after PA-H (-21%), EX-C and EX-H (-28%). EX-C blunted the circulating norepinephrine, cortisol, G-CSF and IL-6 response (P<0.01) but not the plasma epinephrine and serum GH response. These results show a similar neutrophilia and decrease in neutrophil degranulation after prolonged exercise with and without a thermal clamp. As such, the rise in core body temperature does not appear to mediate neutrophil trafficking and degranulation responses to prolonged exercise. In addition, these results suggest a limited role for cortisol, G-CSF and IL-6 in the observed neutrophil responses to prolonged exercise.
