Dehydration characteristics of experienced rock climbers using an indoor rock climbing treadmill

Abstract

To date there are no published studies that quantify the amount of dehydration that takes place during rock climbing (RC). The purposes of this study were to determine whether significant dehydration occurs during a simulated RC session and whether ad libitum water ingestion augments this dehydration. In order to do so, eight male (Mean + or - SD; 26.5 + or - 5.8) and two female (24.0 + or - 1.4 yrs) experienced rock climbers completed two identical 115-minute RC trials on a motorized indoor RC treadmill, which consisted of six 15-minute RC intervals with a five minute rest between each interval. One trial the subjects did not receive water (NH) the other they ingested water ad libitum during the rest periods (AL). Percent change in body mass (%DeltaBM) and percent change in plasma volume (%DeltaPV) were calculated for both trials. Urine specific gravity (USG), rhythmic hand grip endurance and plasma creatine kinase were collected before and after both trials. Heart rate and rating of perceived exertion (RPE) were measured throughout both trials. Data was analyzed via RMANOVA, Wilcoxon signed-rank tests and paired T-tests. The level of significance was set at P< or - 0.05. There were significant differences between trials for %DeltaBM (Mean + or - SE: NH=-2.4 + or - 0.1%, AL=-0.9 + or - 0.2%) and %DeltaPV (NH=-2.93 + or - 2.42%, AL=+8.76 + or - 3.24%). Heart rate and RPE significantly increased during both trials. There was a significant interaction between trials for HR. No other significant differences between trials were observed. Significant dehydration can occur during RC when %DeltaBM is used as an indicator, but not final USG. The cardiovascular stress associated with this dehydration was decreased by ad libitum water ingestion.