The Effects Of Exercise In Thermal Climates On The Liver And Kidney Functions And Related Mechanisms

ObjectiveTo investigate the effect of exercise in thermal climates on the liver and kidney functions and to explore its mechanisms MethodsA total of 187 young soldiers in the subtropical area of Southeast China were selected as subjects.All the subjects underwent off-road race at a distance of 1.5km,3km or 5km in two environmental conditions: normal temperature and normal humidity(temperature(26±2)?,humidity(50±5)%),high temperature and high humidity(temperature(33±2)?,humidity(65±5)%).The venous blood samples were collected before and after exercise for the testing of the following variables.The liver and kidney functions(ALT,AST,ALP,GGT,CR,BUN)and CK,CK-MB,LDH and other muscuclar enzymes and SOD were measured by automatic biochemical analyzer.The levels of serum CRP and HMGB1,8-OHd G,TNF-?,IL-1?,IL-8,IL-18 and LPS were detected by enzyme-linked immunosorbent assay(ELISA).Results(1)The variables of liver and kidney functions(AST,ALT,GGT,Cr and BUN)increased after exercise in both environmental conditions with statistical significance(P<0.05),those in the 3km and 5km groups were significantly different(P<0.05)than in the 1.5km group.The variables of liver and kidney functions(AST,ALT,GGT,Cr and BUN)in the high temperature and high humidity group were significantly higher than those in the normal temperature and normal humidity group(P<0.05);(2)The levels of CK,CK-MB and LDH in the subjects were increased after exercise,which were significantly different from those before exercise(P<0.05).The levels of muscular enzymes increased further with the enhancement of exercise.Compared with the 1.5km group,the differences were statistically significant(P<0.05).The levels of CK,CK-MB and LDH in the 5km high-temperature and high-humidity group were significantly higher than those in the normal temperature and normal humidity group(P<0.05).(3)The levels of LPS and 8-OHd G increased,while the level of SOD decreased compared with that before exercise(P<0.05),and the above variables changed more significantly with the enhancement of exercise.The differences between the 3km group and the 1.5km group,or the 5km and the 1.5km groups were statistically significant(P<0.05).The changes of LPS,SOD and 8-OHd G in the 5km high temperature and high humidity group were the most remarkable after exercise,compared with those in the normal temperature and normal humidity group(P<0.05).(4)The levels of inflammatory factors CRP,HMGB1,IL-1?,IL-8,IL-18 and TNF-? were all increased,compared with those before exercise(P<0.05),and the above variables were further increased with the enhancement of exercise.The difference between the 3km and the 1.5km groups,or the 5km and the 1.5km groups were statistically significant(P<0.05).The levels of CRP,HMGB1,IL-1?,IL-8,IL-18 and TNF-? were the highest in the two groups after 5km exercise,and the difference was statistically significant between the high temperature and high humidity group and the normal temperature and normal humidity group(P<0.05).Conclusion(1)Long time strenuous exercise under the condition of high temperature and high humidity,body is prone to thermal stress injury.The muscle,liver and kidney are vulnerable to thermal stress injury.(2)Endotoxemia and the subsequently triggered systemic inflammatory response is the important mechanism of heat stress injury.(3)The oxidative stress injury triggered by redistributed blood flow and decreased splanchnic flow by strenuous exercise under high temperature and high humidity conditions may also be related to the abnormal liver and kidney function caused by heat stress.