Studies of physiological responses of thermoregulatory, hormonal, and immune in track and field and swimming athletes with spinal cord injury in hot and cold environments

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The purpose of this study was to clarify the influences of exercise-related stress on thermoregulatory, hormonal, and immune responses in hot/cold environments in track and field and swimming athletes with spinal cord injury. The subjects consisted of 5 male wheelchair long-distance athletes with spinal cord injury (wheelchair long-distance athlete group : WLG), 5 male wheelchair-using swimming athletes with spinal cord injury (wheelchair-using swimming athlete group : WSG), 5 healthy male college long-distance athletes (school long-distance athlete group : SLG), and 5 healthy male college swimming athletes (school swimming athlete group : SSG). Informed consent was obtained from all subjects. The measurement periods were September 2007 and December-February in 2007/2008, September-December 2008, and September 2009 and December-March 2009/2010. In 2007, exercise was performed in a climatic chamber at a temperature of 28℃ with 60% RH. In 2008, exercise was performed in a climatic chambe … More r (28℃, 60% RH) while hot (42℃) or cold (15℃) water was circulated through a control tubing suit. In 2007 and 2008, exercise was performed using an arm cranking ergometer at 60%Vo2max for 60 minutes. In 2009 and 2010, exercise was performed on a 400-m track or in a 50-m indoor pool. Concerning the environmental temperature in summer, the air temperature and WBGT of the track were 27 and 29℃, respectively, and the water temperature and WBGT in the indoor pool were 30 and 28℃, respectively. In winter, the air temperature of the track was 12℃, and the water temperature in the indoor pool was 32℃. As track and field exercise, completing a 10,000-m distance within 25 minutes was used for WLG and that within 45 minutes for SLG. As swimming exercise, a 1,000-m freestyle swim within 40 minutes was used for both WSG and SSG. The measurement items were thermoregulatory parameters (such as the perspiration rate, esophageal temperature, mean skin temperature, and osmotic pressure), a hormone (catecholamine), and an immunological parameter (reactive oxygen production by neutrophils). The results were as follows :A. After exercise in a hot environment (summer), no differences were observed in the thermoregulatory or hormonal responses among WLG, WSG, SLG, and SSG. However, immune responses tended to increase more in WLG than in SLG. After exercise in a cold environment (winter), no difference was observed among the 4 groups.B. After exercise at 15 (cold water) or 42℃ (warm water) using the control tubing suit, no differences were observed in thermoregulatory, hormonal, or immune responses among the 4 groups. Using warm water, thermoregulatory responses tended to be poorer in WLG and WSG than in SLG and SSG. Immune responses did not differ among the 4 groups.C. In summer, thermoregulatory responses after the track/swimming event tended to be poorer in WLG than in WSG. In winter, no differences were observed among the 4 groups.These results suggest a risk of heat disorder due to impaired perspiration on exercise at a high temperature in wheelchair athletes with spinal cord injury. Preventive measures such as the use of a cooling jacket are required. In addition, it is important to clarify the degree of perspiration impairment in wheelchair athletes with spinal cord injury. Less