Effect of Fluid Administration on Fluid Consumption and Hydration Status

Abstract

The use of an external fluid administrator (EFA) to deliver fluids is a recent phenomenon in athletics. However, this has yet to be compared to the traditional method of self administration(SA). PURPOSE: To examine the influence fluid administration methods have on fluid consumption, hydration status, and perceptual variables. METHODS: Nineteen recreationally active individuals [14 males, 5 females (30±10y; 176±8cm; 72.5Kg) participated in two days of exercise with varying the method of fluid administration (self-administration SA; external fluid administration EFA) between days. EFA refers to when someone else squirts water into the participant’s mouth, whereas SA, the participant squirts water into their own mouth. The water bottle (WB) was kept equal distance from the mouth for both conditions. Participants weight (t-shirt and/or shorts only) and urine samples were collected prior to exercise. Participants then completed a 10-min warm-up. Participants had a 2-min fluid break before the exercise protocol (EP), which included a series of five 15-minute stations. Exercises provided aerobic and anaerobic demands, including hill jogging, push-ups, jumping jacks, ladder drills, and intermittent rest. After completing each station, participants received a 5-min fluid breaks where they drank ad libitum. Fluid variables and perceptual variables were collected during every fluid break. Following the final fluid break,participants provided a post-exercise weight and urine sample. The order of conditions and exercise stations were randomly assigned. Fluid variables assessed were volume consumed perfluid break (VC/FB), number of squirts per fluid break (#Sq/FB), squirt volume per fluid break (SqV/FB), total squirts (TSq), total volume consumed (TVC), and average volume per squirt (AV/Sq). Hydration status was assessed via urine specific gravity (USG), body mass loss (BML),sweat loss (SwL), and sweat rate (SwRt). Perceptual measures assessed include thirst and fullness. Repeated-measures ANOVA was used to analyze condition by time for VC/FB,#Sq/FB, SqV/FB, USG, thirst and fullness. A paired t-test was used for post-hoc analysis.Independent samples t-tests were used to analyze TSq, TVC, AV/Sq, BML, SwL, and SwRt.P<0.05 a priori RESULTS: No significant interaction was indicated for VC/FB or SqV/FB (p>0.05). A significant interaction was noted for #Sq/FB (p<0.05). TSq between conditions did not indicate significance, however TVC and AV/Sq were significantly different (p<0.05). With no significant interaction for USG, participants arrived (SA=1.016±.009; EFA=1.019±.008) and remained (SA=1.019±.008; EFA=1.020±.007) hydrated throughout the EP. BML, SwL, SwRt, thirst and fullness also indicated no significant differences between conditions (p>0.05). CONCLUSION: SA promoted more TVC likely due to greater VSq. Both conditions remained euhydrated, but EFA consumed less fluids. Euhydration may have been maintained because of regularly spaced fluid breaks and when regular fluid breaks are unavailable, EFA may result in more BML and hypohydration.