Validity of an acoustic method to assess whole-body hydration status Free

Athletes and the elderly are two populations that are at an increased risk of dehydration related illness or injury. The purpose of this study was to evaluate the validity of an acoustic method to detect changes in the hydration status of athletes undergoing acute dehydration and rehydration. The presence or absence of dehydration in elderly individuals throughout the day and between days, was also examined. The assessment of water balance was conducted by measuring speed of ultrasound in the calf muscles using a through transmission method. 82 male and female collegiate athletes and 20 elderly individuals were assessed. Results revealed an average change in ultrasound velocity of 1.1 m/s per 1% of body weight lost. This demonstrates that ultrasound velocity in muscle may potentially serve as a measure of body hydration status during acute dehydration and as a diagnostic tool in the elderly. However, the ultrasound velocity measurement method used in this study is highly dependent on the positioning of the probe: even slight variation in the acoustic path results in significant changes in the measured values, which may result in unacceptable error. A solution to this problem is proposed and discussed. [NIH2R44AG042990]