Consistently High Urine Specific Gravity in Adolescent American Football Players and the Impact of an Acute Drinking Strategy

Abstract

The purpose of this study was to determine whether high-school football players showed risks of fluid deficits during two-a-day training (Part 1), and whether implementing a drinking strategy could acutely improve the markers of hydration (Part 2). In Part 1, pre-training urine specific gravity (USG) and pre- and post-training body weight were measured at the morning session for 5 consecutive days of two-a-day practices to monitor the hydration status of 13 varsity players. The mean pre-training body weight was consistently lower (mean decrease of 0.5 kg, p<0.05) following the first day of measurement. Pre-training USG values remained consistently high each day (range for daily means: 1.022+/-0.003 to 1.024+/-0.005). Part 2 consisted of assessing hydration status in 46 varsity and junior varsity players prior to morning training during two-a-day training before and following implementing a drinking strategy. In association with the strategy, mean body weight increased 0.5 kg (p<0.01) and mean USG decreased from 1.021 to 1.016 (p<0.01) following the drinking protocol. The slight decline in body weight and consistently high USG (Part 1) suggested that standard fluid replacement strategies were less than optimal for a majority of the players. Implementing a drinking strategy appeared to improve hydration status based on changes in body weight and USG (Part 2).

Comparison of Wired and Wireless Bio-Electrical Impedance Fluid Status Monitoring Devices and Validation to Body Mass and Urine Specific Gravity Changes Following Mild Dehydration

“…Both of these differences were statistically significant (p < 0.001) and similar to previous findings (Koulmann et al 2000;Stover et al 2006). ZOE2 and ZOEW measurements, however, were not statistically different from pre-to post-practice.…”

Youth Football: Heat Stress and Injury Risk

“…Stover et al (89) observed moderate rates of sweating (Ͻ1 L·h Ϫ1 ) and small body weight deficits (about 1%) in high school players during preseason practice. These measures were slightly lower than losses described in collegiate players training in similar moderate (wet bulb globe temperature [WBGT] 25°C) environmental conditions (87).…”

Assessment of construction workers’ hydration status using urine specific gravity

“…This finding is in compliance with the study of Bates et al [15] that showed that heat management based on environmental monitoring but without addressing the hydration issue cannot protect workers from the effects of heat stress. Also Stover et al in his study on dehydration status among high school football players used USG as the marker of dehydration and showed that pre-training USG values remained consistently high each day (range for daily means: 1.022±0.003 to 1.024±0.005) and implementation of a new drinking strategy was required to maintain hydration [17]. Study of Bates and Schneider [3] on hydration status and physiological workload of UAE construction workers, showed that against very hot climatic conditions, where workers are receiving enough fluids and are well hydrated before the work shift, their hydration status was in the normal range.…”