| Research Abstract |
The purpose of this study was to clarify the influences of exercise stress in hot and cold environments on thermoregulation, perspiration rate, osmotic pressure, hormones, and immunity in athletes with spinal cord injury. The subjects were 5 wheelchair marathon participants (M-G) and 5 wheelchair basketball players (B-G) with spinal cord injury and 10 healthy male University students (U-G). Measurements were performed in a climate chamber under the following 3 conditions (A-C) in summer (July-September) and winter (January-March) in 2004 and 2005 and in summer in 2006 : A) at a chamber temperature of 28℃ in both summer and winter in 2004 (neutral temperature range), B) at a chamber temperature of 12℃ in summer (cold exposure) and 35℃ in winter (heat exposure) in 2005, and C) circulation of cold water (15℃) or warm water (42℃) through a temperature control suit applied to the upper half of the body at a chamber temperature of 28℃ in summer in 2006. Under each condit on, exercise was per
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formed using an arm cranking ergometer at 60%Vo2max for 60 minutes. The measurement items were the cardiac rate, sweat rate (SW), heat production (HP), mean skin temperature (Tsk), tympanic temperature (Tty), osmotic pressure (OSM), catecholamine (CA), and neutrophil oxidative capacity.
A. At rest in summer and winter, SW, HP, Tsk, Tty, OSM, and CA at a neutral temperature were similar among M-G, B-G, and U-G. During exercise in summer, SW, HP, Tsk, Tty, OSM, CA, and neutrophil oxidative capacity were slightly higher in M-G and B-G than in U-G. In winter, SW, HP, Tsk, Tty, and CA were similar among the 3 groups after the initiation of exercise, at the end of exercise.
B. Under cold exposure in summer, SW, HP, Tsk, Tty, and CA were similar among the 3 groups, while neutrophil oxidative capacity was slightly higher in M-G and B-G than in U-G. Under heat exposure in winter, SW, HP, Tsk, Tty, OSM, and CA were higher in M-G and B-G than in U-G.
C. During exercise using a temperature control suit under cold water circulation (15ーC), SW, HP, Tsk, Tty, and CA did not differ among the 3 groups. Under warm water circulation (42℃), SW, HP, Tsk, Tty, OSM, and CA were higher in M-G and B-G than in U-G. Neutrophil oxidative capacity under cold or warm water circulation was similar among the 3 groups.
Thus, in a hot environment, thermoregulation sensitivity and heat production responses were poorer in M-G and B-G than in U-G, suggesting the influences of spinal cord injury on thermoregulation during exercise in a hot environment. Neutrophil oxidative capacity was increased by 60%VoD2max. Less
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