PURPOSE: The purpose of this study was to determine the effect of thermal stress and hydration status on immune function during exercise. METHODS: Ten trained men completed four cycle ergometer rides at 55% VO2peak under the following conditions: EN (euhydrated neutral; 22 degrees C, 30% RH), DN (dehydrated neutral), EH (euhydrated hot; 38 degrees C, 45% RH), and DH (dehydrated hot). During EN and EH, a carbohydrate/electrolyte beverage was consumed at a rate matching sweat loss, and during DN and DH, no fluid was ingested. Blood samples were drawn pre- and postexercise, and at 2 and 24 h of recovery. Cell counts were determined by automated counting and flow cytometry. Neutrophil activity was assessed as superoxide production, lymphocyte function was determined via PHA-stimulated mitogenesis, and natural killer (NK) cell activity was measured with a 51Cr-release assay. Cortisol was assayed via RIA. RESULTS: Lymphocytes proliferation was depressed 2 h after exercise in all conditions (P < 0.05); however, when expressed on a per cell basis, function was greater in the DH and EH conditions. NK activity (max x 10(3) cells) was greater post compared with preexercise in all conditions (EH = 25.5 +/- 16.8, DH = 26.2 +/- 10.5, EN = 19.3 +/- 11.0, and DN = 16.5 +/- 8.7) but was not different between conditions. Leukocyte, neutrophil, lymphocyte, and NK cell counts were also elevated postexercise with the former two remaining elevated 2 h postexercise in the EH and DH conditions. Cortisol was greater postexercise in EH (22.1 +/- 1.3) and DH (27.7 +/- 1.3) compared with EN (17.8 +/- 2.1) and DN (18.9 +/- 1.6 microg x dL(-1). CONCLUSION: Euhydration did not affect cell number or function when compared with a dehydrated state; however, the hot environment caused more severe disturbances in these measures compared with a neutral environment.
PURPOSE: The purpose of this study was to determine the effect of thermal stress and hydration status on immune function during exercise. METHODS: Ten trained men completed four cycle ergometer rides at 55% VO2peak under the following conditions: EN (euhydrated neutral; 22 degrees C, 30% RH), DN (dehydrated neutral), EH (euhydrated hot; 38 degrees C, 45% RH), and DH (dehydrated hot). During EN and EH, a carbohydrate/electrolyte beverage was consumed at a rate matching sweat loss, and during DN and DH, no fluid was ingested. Blood samples were drawn pre- and postexercise, and at 2 and 24 h of recovery. Cell counts were determined by automated counting and flow cytometry. Neutrophil activity was assessed as superoxide production, lymphocyte function was determined via PHA-stimulated mitogenesis, and natural killer (NK) cell activity was measured with a 51Cr-release assay. Cortisol was assayed via RIA. RESULTS: Lymphocytes proliferation was depressed 2 h after exercise in all conditions (P < 0.05); however, when expressed on a per cell basis, function was greater in the DH and EH conditions. NK activity (max x 10(3) cells) was greater post compared with preexercise in all conditions (EH = 25.5 +/- 16.8, DH = 26.2 +/- 10.5, EN = 19.3 +/- 11.0, and DN = 16.5 +/- 8.7) but was not different between conditions. Leukocyte, neutrophil, lymphocyte, and NK cell counts were also elevated postexercise with the former two remaining elevated 2 h postexercise in the EH and DH conditions. Cortisol was greater postexercise in EH (22.1 +/- 1.3) and DH (27.7 +/- 1.3) compared with EN (17.8 +/- 2.1) and DN (18.9 +/- 1.6 microg x dL(-1). CONCLUSION: Euhydration did not affect cell number or function when compared with a dehydrated state; however, the hot environment caused more severe disturbances in these measures compared with a neutral environment.
Authors: J Romeo; D Jiménez-Pavón; M Cervantes-Borunda; J Wärnberg; S Gómez-Martínez; M J Castillo; A Marcos Journal: J Physiol Biochem Date: 2008-09 Impact factor: 4.158
Authors: Laura L Jelliffe-Pawlowski; Gary M Shaw; David K Stevenson; John W Oehlert; Cele Quaintance; Allan J Santos; Rebecca J Baer; Robert J Currier; Hugh M O'Brodovich; Jeffrey B Gould Journal: Pediatr Res Date: 2012-02-15 Impact factor: 3.756
Authors: Dominique D Gagnon; Sheila S Gagnon; Hannu Rintamäki; Timo Törmäkangas; Katri Puukka; Karl-Heinz Herzig; Heikki Kyröläinen Journal: PLoS One Date: 2014-10-22 Impact factor: 3.240