Impact Of Acute Exercise In Different Relative Humidity And Hot Environment On The Function Of Neuroendocrine And Immune System

Objective To investigate the effect of exercise in the hot of different relative humidity environment on the human endocrine and immune relative index,Evaluate the relative humidity on the stress degree and possible signal transition of thermoregulation when exercise in the hot environment.Human study Methods: 20 male subjects(mean age,21.7±1.13years;mean training years,3.9±0.87years)were employed in the experiment and randomly assigned exposure group and exercise group.The temperature was 33?,the relative humidity include 20%,40%,60%,80%,the exercise group conducted treadmill exercise while the exposure group seat in the same environment.The ELISA was used for the determination of serum PRL,GH,cortisol,IL-1,IL-6,IL-12 and plasma HSP72 before and after exercise.Results: The mean skin temperature of all the groups was significantly different after exercise,the control group was lowest,as the relative humidity increased the mean skin temperature increased.The serum PRL,GH and cortisol significantly increased after exercise,but not in the exposure groups.The serum PRL of RH 60% group was significantly higher than RH20% group(P<0.01)after exercise.The serum cortisol of RH 80% group was higher than RH20% group after exercise,but the exposure group of RH80% was significantly lower than the group of RH 20%.The plasma HSP72 of all the groups significantly improved after exercise except for the group of relative humidity 40%.There has a “U” curve relationship between the relative humidity and plasma HSP72 of after exercise.The serum IL-1 and IL-12 both decreased after exercise,and IL-12 decreased significantly,the exposure group IL-12 also had decreased,but had no significant.The serum IL-6 increased after exercise,but had no significant.Animal study Methods: Rats random divided into exercise group and control group,the exercise group further divided into normal temperature group,33? group and 38? group.The Room temperature achieved by intelligent heating system.The exercise group running speed was 22m/min,5% slope.Observe the rats behavior changes and the the duration to exhaustive.Immunohistochemistry methods was used to observe the expression and number of c-fos,HSP70 and HSF1 Positive neurons in the PVN and MPA.Results: Rectal temperature increased significantly after exercise,the hot environment exercise group increased further more and exercise duration was significantly shorter than the normal temperature.The immunohistochemical staining result show that the c-fos Positive neurons increased slightly and it increased significantly in the 33?,c-fos Positive neurons peaked at 38?.We did not find the HSP70 positive neurons increased in the PVN and MPA after exercise in the normal temperature and very few HSF1 positive neurons,but the HSP70 and HSF1 positive neurons significantly increased after exercise in the 38?.Conclusion The relative humidity affect the heat loss when exercise in the hot environment,the relative too high or too low the body will have a great heat shock response?There maybe have a idea environment which adapt the human to exercise the relative humidity between 20% and 60% in the hot environment.The exercise capacity decline in the hot environment may be related to the hypothalamus-pituitary-adrenal axis impairment.In this study the rats exercise duration in the hot environment was significantly shorter,the immunohistochemical staining result show that the c-fos,HSP70 and HSF1 significantly expressed in the PVN and MPA,this suggested that the PVN and MPA was activated and may be damaged.The serum PRL is a good index of body temperature,between the serum PRL and oral temperature have positive correlation,it can be reflect the degree of heat stress.Exercise in the hot environment,the changes of the neuroendocrine had an increased trend as the relative humidity increased.Exercise in the same temperature,but the stress is different when the relative humidity is different.