Immune function during and after 60 min of moderate exercise wearing protective clothing.
BACKGROUND
As exercise while wearing protective clothing exacerbates body heat storage compared to exercise in the heat, and as exercise alters immune responses, it appeared worthwhile to examine immune and stress responses while wearing protective clothing during moderate exercise.


METHODS
Eight subjects completed two bouts of exercise at 45% Vo2(max) in a thermoneutral environment: once while wearing shorts only (Control trial, CON) and again while wearing protective clothing (PRO). Venous blood samples were taken to analyze TNF-alpha mRNA by RT-PCR in LPS stimulated blood, plasma catecholamines, and cortisol. Blood cell count was analyzed by flow cytometry. Rectal temperature (T(re)) was monitored continuously.


RESULTS
Exercise with PRO resulted in significantly greater increases in T(re) (39.2 +/- 0.2 degrees C in PRO vs. 38.0 +/- 0.1 degrees C in CON) and plasma epinephrine and norepinephrine (+70% and 150%, respectively). Plasma cortisol increased only at the end of PRO exercise (+33%). Leukocyte and lymphocyte cell count was 14% and 18% higher, respectively, but there were no significant changes in T cytotoxic and NK cell counts compared to the CON trial. Only T helper lymphocyte count was lower (-29%). During both exercise trials, T helper lymphocytes were significantly decreased at the end of exercise and recovery. With or without protective clothing, exercise was associated with an inhibition of TNF- alpha expression in stimulated monocytes (approximately -50% at min 20 and 40, and approximately -30% at min 60).


CONCLUSIONS
Protective clothing wearing induces significant thermal challenge during exercise. The inhibition of TNF-alpha appears to be mediated primarily by exercise and not the added thermal load associated with protective clothing.
Jimenez
Chantal
C
Département des facteurs humains, Centre de Recherches du Service de Santé des Armées, La Tronche, France. chantal.jimenez@gmail.com
Mathieu
Jacques
J
Peinnequin
André
A
Carter
Robert
R
Alonso
Antonia
A
Melin
Bruno
B
D000328:Adult; D002395:Catecholamines / Q000097:blood; D018592:Cross-Over Studies; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005334:Fever / Q000276:immunology*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D011481:Protective Clothing / Q000009:adverse effects*; D016176:T-Lymphocyte Subsets / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000097:blood*
D002395:Catecholamines; D014409:Tumor Necrosis Factor-alpha; D006854:Hydrocortisone