Cortisol and testosterone concentrations in wheelchair athletes during submaximal wheelchair ergometry

It is vet unknown how upper body exercise combined with high ambient temper atures affects plasma testosterone and cortisol concentrations and furtherm ore, how these hormones respond to exercise in people suffering spinal cord injuries. The purpose of this study was to characterize plasma testosteron e and cortisol responses to upper body exercise in wheelchair athletes (WA) compared to able-bodied individuals (AB) at two ambient temperatures. Four WA [mean age 36 (SEM 13) years, mean body mass 66.9 (SEM 11.8) kg, injury level T-7-T-11], matched with five AB [[mean age 33.4 (SEM 8.9)years, mean body mass 72.5 (SEM 13.1) kg] exercised (cross-over design) for 20 min on a wheelchair ergometer (0.03 kg resistance . kg(-1) body mass) at 25 degrees C and 32 degreesC. Blood samples were obtained before (PRE), at min 10 (MID ), and min 20. (END) of exercise. No differences were found between results obtained at 25 degreesC and 32 degreesC for any physiological variable stu died and therefore these data were combined. Pre-exercise testosterone conc entration was lower (P < 0.05) in WA [18.3 (SEM 0.9) nmol . l(-1)] compared to AB [21.9 (SEM 3.6) nmol . l(-1)], and increased PRE to END only in WA. Cortisol concentrations were similar between groups before and during exerc ise, despite higher rectal temperatures in WA compared to AB, at MID [37.21 (SEM 0.14) and 37.02 (SEM 0.08)<degrees>C, respectively] and END [37.36 (SE M 0.16) and 37.19 (SEM 0.10)degreesC, respectively]. Plasma norepinephrine responses we:re similar between groups. In conclusion, there were no differ ences in plasma cortisol concentrations, which major have been due to the l ow relative exercise intensities employed. The greater exercise response in WA for plasma testosterone should be confirmed on a larger population. It could have been the result of the lower plasma testosterone concentrations at rest in our group.