Urinary specific gravity measures in the U.S. population: Implications for the adjustment of non-persistent chemical urinary biomarker data

OBJECTIVE: Marching band musicians often endure prolonged daily practices in warm-hot outdoor environments. Evaluation of hydration status by instrument position can shed light on health-related issues for these performers. The objective of this study was: a) to determine the effects of playing position on hydration status based on urinary biomarkers (urinary specific gravity and urinary osmolality) before and after marching band practice, and b) to evaluate the relation of hydration status with body mass change and fluid consumption for all playing positions. METHODS: Fifty-eight collegiate marching band players participated in this study, involving five playing positions: band pit (n=10), baritone and euphonium (n=12), snare drum (n=13), trumpet (n=12), and tuba (n=11). All participants performed their own routine marching band practice, which lasted a total of 6 hrs on 1 day. Each individual consumed ad libitum commercially available carbohydrate-electrolyte solution during the practice. To determine hydration status, urine samples were collected before and after practice for analysis of urinary specific gravity and urinary osmolality. Body weight and total fluid intake were also assessed pre- and post-exercise. RESULTS: There were no significant effects for playing position and time or interaction concerning the levels of urinary osmolality and specific gravity after practice. CONCLUSIONS: Our main findings suggest that hydration status may be similar among the different playing positions following prolonged practice in the outdoor environment.

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Hydration and Urinary Pseudoephedrine Levels After a Simulated Team Game

International Journal of Sport Nutrition and Exercise Metabolism ◽

10.1123/ijsnem.2013-0076 ◽

2014 ◽

Vol 24 (3) ◽

pp. 325-332 ◽

Cited By ~ 2

Author(s):

Daniel Jolley ◽

Brian Dawson ◽

Shane K. Maloney ◽

James White ◽

Carmel Goodman ◽

...

Keyword(s):

Specific Gravity ◽

Body Mass ◽

Drug Administration ◽

Hydration Status ◽

Half Time ◽

Fluid Bolus ◽

Ph Values ◽

Urinary Specific Gravity ◽

Urinary Levels ◽

Team Game

This study investigated the influence of dehydration on urinary levels of pseudoephedrine (PSE) after prolonged repeated effort activity. Fourteen athletes performed a simulated team game circuit (STGC) outdoors over 120 min under three different hydration protocols: hydrated (HYD), dehydrated (DHY) and dehydrated + postexercise fluid bolus (BOL). In all trials, a 60 mg dose of PSE was administered 30 min before trial and at half time of the STGC. Urinary PSE levels were measured before drug administration and at 90 min postexercise. In addition, body mass (BM) changes and urinary specific gravity (USG), osmolality (OSM), creatinine (Cr), and pH values were recorded. No differences in PSE levels were found 90 min postexercise between conditions (HYD: 208.5 ± 116.5; DHY: 238.9 ± 93.5; BOL: 195.6 ± 107.3 μg·ml−1), although large variations were seen within and between participants across conditions (range: 33–475 μg·ml−1: ICC r = .03–0.16, p > .05). There were no differences between conditions in USG, OSM, pH or PSE/Cr ratio. In conclusion, hydration status did not influence urinary PSE levels after prolonged repeated effort activity, with ~70% of samples greater than the WADA limit (>150 μg.ml−1), and ~30% under. Due to the unpredictability of urinary PSE values, athletes should avoid taking any medications containing PSE during competition.

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