Effect of the Seasonal Adaptability on Carbohydrate-electrolyte Beverage Efforts on Post-exercise Rehydration in Healthy Young Men

Abstract

Objective To compare the effects of carbohydrate-electrolyte beverage on post-exercise rehydration of healthy young men in different seasons,and to explore the influence of seasonal adaptability on fluid and electrolyte balance.Methods Fifteen healthy men,aged(24.4±0.5)years,completed 2 trails in a random crossover design both in summer and winter.During recovery,they consumed a drink volume equivalent to 100% of their sweat loss with plain boiled water(the water group)or carbohydrate-electrolyte beverage(the beverage group).Recovery was monitored for further 180 minutes by the collection of blood and urine samples.Results The dehydration time in summer was significantly shorter by about 20 minutes than that in winter(t=3.045,P=0.004).In summer,the fluid retention rate of the beverage group was significantly higher than that of the water group at 120 minutes after rehydration [(83.7±2.8)% vs.(73.7±3.7)%,F=5.312,P=0.028],and significantly higher than the water group at 180 minutes [(74.8±3.6)% vs.(66.1±4.3)%,F=4.340,P=0.046].In winter,the fluid retention rate of the beverage group at 180 minutes after rehydration was significantly higher than that of the water group [(74.9±4.7)% vs.(68.0±6.0)%,F=4.128,P=0.048].There was no significantly seasonal difference in the fluid retention effect of carbohydrate-electrolyte beverage at 180 minutes after rehydration.In the beverage group,the changes of blood glucose and serum sodium levels(all P<0.05)in summer were significantly higher than those in winter at 10-180 minutes after rehydration,and the fractional excretion of sodium in summer was significantly higher in summer than in winter at 120 and 180 minutes after rehydration(F120=4.972,P=0.034;F180=8.425,P=0.007);however,there was no significant difference in plasma osmolality(all P> 0.05).For the water group,the plasma osmolality in winter was lower than that in summer,while the degree of dryness and thirst was higher in winter than in summer.Conclusions Seasonal adaptability influenced the hydration status and its regulating factors.People dehydrated faster after exercise in summer than in winter,and the hydration status was relatively stable in winter.However,in summer,the blood glucose and electrolytes responded more rapidly to carbohydrate-electrolyte beverage supply,and the plasma osmolality and subjective perception recovered faster.Therefore,during the 180-minute recovery period,the carbohydrate-electrolyte beverage had a higher rehydration efficiency in a short recovery time in summer although there was no significantly seasonal difference in the fluid retention rate.