Effects Of Caffeine Intake At Different Temperatures On Saliva SIgA,LZM And SAA In Endurance Athletes’ Exercise

Research purposes: In this paper,we studied the effects of long-term exercise on salivary secretory immunoglobulin A(sIgA),salivary lysozyme(LZM)and salivary amylase(sAA)in endurance athletes at different temperatures after caffeine intake.To explore the effect of caffeine on human mucosal immune function at different temperatures,so as to provide theoretical basis for formulating exercise prescriptions.Research methods: This study adopted a single blind,randomized cross-over experimental design method.Twelve male postgraduates and college athletes from Physical Education College of Hebei Normal University were selected as subjects(height: 176.75±8.16 cm,weight: 75.15±8.85 kg,age: 24.95±1.24 y,exercise duration: 6.45±1.75y).The laboratory temperature of the low temperature group was controlled at about 5 C and the relative humidity was about 60%.The laboratory temperature of the normal temperature group was controlled at about 23 C and the relative humidity was about 60%.Twelve subjects exercised on a power bicycle for one hour with 70% maximum oxygen uptake intensity.Four experiments(normal temperature CAF,normal temperature control,low temperature CAF,low temperature control)were carried out respectively.Each experiment was conducted at least 7 days apart.In the CAF group,the saliva was taken orally immediately after the first saliva collection(3ml/kg body weight),and caffeine(6mg/kg body weight)was added.In the control group,the same amount of sports drink was taken orally without caffeine.In each experiment,saliva samples were collected 60 minutes before exercise,immediately after exercise,30 minutes after exercise,60 minutes after exercise and 60 minutes after exercise.The concentration of sIgA,LZM and sAA in saliva was measured,and the secretion rates of sIgA,LZM and sAA in saliva were calculated.The saliva index data of each group were processed by SPSS 20.0 software.The results are as follows:(1)The concentration and secretion rate of sAA in saliva of CAF group at 60 minutes before exercise were significantly higher than those of saliva at 60 minutes before exercise(all P < 0.05);the concentration and secretion rate of sAA in saliva of control group at 60 minutes before exercise were higher than those of saliva at 60 minutes before exercise(all P < 0.05);the concentration and secretion rate of sAA in saliva at each time point were higher than those of exercise(P < 0.05).There was no significant difference in degree and secretion rate(P > 0.05).The concentration and secretion rate of sAA in saliva of 60 minutes before exercise in hypothermia CAF group were higher than those of 60 minutes before exercise(P < 0.05);the concentration and secretion rate of sAA in saliva of 60 minutes before exercise in hypothermia control group were higher than those of 60 minutes before exercise(P < 0.05);the concentration and secretion rate of sAA in saliva of 60 minutes before exercise in hypothermia control group were higher than those of 60 minutes after exercise(P < 0.05).The difference was not significant(P > 0.05).(2)The concentration and secretion rate of sIgA in saliva of CAF group were lower than that of 60 minutes before exercise(P < 0.05);the concentration and secretion rate of sIgA in saliva of CAF group were not significantly different between 60 minutes before exercise and 60 minutes after exercise(all P > 0.05);the comparison between CAF group and normal temperature control group showed that the concentration and secretion rate of sIgA in saliva of each point were not significant(P > 0.05).There was no significant difference in concentration and secretion rate(P > 0.05).The concentration and secretion rate of sIgA in saliva of hypothermia CAF experimental group were significantly lower than that of exercise 60 minutes before exercise(p < 0.05);the concentration and secretion rate of sIgA in saliva of hypothermia control group were significantly higher than that of exercise 60 minutes before exercise,and the difference was significant;compared with the control group,the concentration and secretion rate of sIgA in saliva of exercise 60 minutes were significantly higher than that of exercise 60 minutes before exercise(P < 0.05).There was no significant difference among the other groups(P > 0.05).(3)The salivary LZM concentration and secretion rate in CAF group were significantly lower than those in 60 minutes before exercise(P < 0.05);the salivary LZM concentration and secretion rate in normal temperature control group were significantly lower than those in 60 minutes before exercise(P < 0.05);the salivary LZM concentration and secretion rate in CAF group were significantly lower than those in 60 minutes before exercise(P < 0.05).There was no significant difference in each point(P > 0.05).The concentration and secretion rate of salivary LZM in hypothermia group were lower than that in exercise group 60 minutes before exercise(P < 0.05).The concentration and secretion rate of salivary LZM in control group were not different between 60 minutes before exercise and 60 minutes before exercise(P > 0.05).The concentration and secretion rate of salivary LZM in CAF group were significantly higher than that in control group at 30 minutes and 60 minutes after exercise(P > 0.05).There was significant difference(P < 0.05),but there was no significant difference in other time points(P > 0.05).Research conclusions:(1)Caffeine had no effect on salivary sAA during intensive exercise at room temperature,but increased the concentration and secretion rate of sIgA and inhibited the concentration and secretion rate of salivary LZM.Intensive exercise at room temperature decreased the concentration and secretion rate of sAA,but had no effect on sIgA in saliva,and increased the concentration and secretion rate of LZM.(2)Caffeine had no effect on salivary sAA during intensive exercise at low temperature,and increased the concentration and secretion rate of sIgA and salivary LZM.Low temperature and high intensity exercise reduced the concentration and secretion rate of sAA and slgA,but had no effect on LZM.(3)Taking caffeine can improve the concentration and secretion rate of sIgA and LZM in athletes,and thus improve the mucosal immunity.