The Acute Effects of Fluid Intake on Urine Specific Gravity and Fluid Retention in a Mildly Dehydrated State

2013 ◽  
Vol 27 (4) ◽  
pp. 1002-1008 ◽  
Author(s):  
Heather M. Logan-Sprenger ◽  
Lawrence L. Spriet
Keyword(s):  
Specific Gravity ◽  
Fluid Intake ◽  
Fluid Retention ◽  
Urine Specific Gravity ◽  
Acute Effects

Fluid Retention and Utility of Practical Hydration Markers to Detect Three Levels of Recovery Fluid Intake in Male Runners

2017 ◽  
Vol 27 (2) ◽  
pp. 178-185 ◽  
Author(s):  
Mary Caitlin Stevenson Wilcoxson ◽  
Samantha Louise Johnson ◽  
Veronika Pribyslavska ◽  
James Mathew Green ◽  
Eric Kyle O’Neal
Keyword(s):  
Specific Gravity ◽  
Urine Output ◽  
Fluid Intake ◽  
Fluid Retention ◽  
Fluid Replacement ◽  
Urine Specific Gravity ◽  
Retention Data ◽  
Sweat Loss ◽  
Ad Libitum ◽  
Low Levels

Runners are unlikely to consume fluid during training bouts increasing the importance of recovery rehydration efforts. This study assessed urine specific gravity (USG) responses following runs in the heat with different recovery fluid intake volumes. Thirteen male runners completed 3 evening running sessions resulting in approximately 2,200 ± 300 ml of sweat loss (3.1 ± 0.4% body mass) followed by a standardized dinner and breakfast. Beverage fluid intake (pre/postbreakfast) equaled 1,565/2,093 ml (low; L), 2,065/2,593 ml (moderate; M) and 2,565/3,356 mL (high; H). Voids were collected in separate containers. Increased urine output resulted in no differences (p > .05) in absolute mean fluid retention for waking or first postbreakfast voids. Night void averages excluding the first void postrun (1.025 ± 0.008; 1.013 ± 0.008; 1.006 ± 0.003), first morning (1.024 ± 0.004; 1.015 ± 0.005; 1.014 ± 0.005), and postbreakfast (1.022 ± 0.007; 1.014 ± 0.007; 1.008 ± 0.003) USG were higher (p < .05) for L versus M and H respectively and more clearly differentiated fluid intake volume between L and M than color or thirst sensation. Waking (r = -0.66) and postbreakfast (r = -0.71) USG were both significantly correlated (p < .001) with fluid replacement percentage, but not absolute fluid retention. Fluid intake M was reported as most similar to normal consumption (5.6 ± 1.0 on 0–10 scale) after breakfast and equaled 122 ± 16% of sweat losses. Retention data suggests consumption above this level is not warranted or actually practiced by most runners drinking ad libitum, but that periodic prerun USG assessment may be useful for coaches to detect runners that habitually consume low levels of fluids between training bouts in warm seasons.

The Urine Specific Gravity Dipstick: A Useful Tool to Increase Fluid Intake in Stone Forming Patients

1991 ◽  
Vol 146 (6) ◽  
pp. 1475-1477 ◽  
Author(s):  
Michael McCormack ◽  
Jean Dessureault ◽  
Michel Guitard
Keyword(s):  
Specific Gravity ◽  
Fluid Intake ◽  
Urine Specific Gravity

scholarly journals Pregame Urine Specific Gravity and Fluid Intake by National Basketball Association Players During Competition

2009 ◽  
Vol 44 (1) ◽  
pp. 53-57 ◽  
Author(s):  
Kristin L. Osterberg ◽  
Craig A. Horswill ◽  
Lindsay B. Baker
Keyword(s):  
Specific Gravity ◽  
Fluid Intake ◽  
Volume Of Fluid ◽  
Cross Sectional Study ◽  
National Basketball Association ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Sweat Loss ◽  
Cross Sectional ◽  
Basketball Game

Abstract Context: Urine specific gravity (USG) has been used to estimate hydration status in athletes on the field, with increasing levels of hypohydration indicated by higher USG measurements (eg, greater than 1.020). Whether initial hydration status based on a urine measure is related to subsequent drinking response during exercise or athletic competition is unclear. Objective: To determine the relationship between pregame USG and the volume of fluid consumed by players in a professional basketball game. Design: Cross-sectional study. Setting: Basketball players were monitored during Summer League competition. Patients or Other Participants: Players (n  =  29) from 5 teams of the National Basketball Association agreed to participate. Main Outcome Measure(s): Pregame USG was measured for each player on 2 occasions. Athletes were given ad libitum access to fluid during each game and were unaware of the purpose of the study. Volume of fluid intake was measured for each player. To assess sweat loss, athletes were weighed in shorts before and after each game. Results: Sweat loss ranged from 1.0 to 4.6 L, with a mean sweat loss of 2.2 ± 0.8 L. Fluid intake ranged from 0.1 to 2.9 L, with a mean fluid intake of 1.0 ± 0.6 L. Pregame USG was greater than 1.020 in 52% of the urine samples collected and was not correlated with fluid volume consumed during either of the games (r  =  0.15, P  =  .48, and r  =  0.15, P  =  .52, respectively). Conclusions: Approximately half of the players began the games in a hypohydrated state, as indicated by USG. Fluid intake during the game did not compensate for poor hydration status before competition. Furthermore, sweat losses in these players during games were substantial (greater than 2 L in approximately 20 minutes of playing time). Therefore, both pregame and during-game hydration strategies, such as beverage availability and player education, should be emphasized.

The Timing of Fluid Intake during an Olympic Distance Triathlon

2006 ◽  
Vol 16 (6) ◽  
pp. 611-619 ◽  
Author(s):  
Robert McMurray ◽  
David K. Williams ◽  
Claudio L. Battaglini
Keyword(s):  
Heart Rate ◽  
Specific Gravity ◽  
Oxygen Uptake ◽  
Perceived Exertion ◽  
Fluid Intake ◽  
Rating Of Perceived Exertion ◽  
Urine Specific Gravity ◽  
Cycle Phase ◽  
Performance Time ◽  
Overall Performance

Seven highly trained male triathletes, aged 18 to 35 years, were tested during two simulated Olympic distance triathlons to determine whether run performance was enhanced when consuming 177 ml of water at 8, 16, 24, and 32 kilometers (Early Trials) compared to consumption at 10, 20, 30, and 40 kilometers (Late Trials), during the cycling segment of the triathlon. Swim times for 1500 m were similar between trials; 40-km cycling times were ~10 s faster during the Late trials; however, 10-km run times were faster during the Early Trials (P < 0.02). No significant differences between run trials were found for the rating of perceived exertion, oxygen uptake, heart rate, and change in urine specific gravity. It was concluded that the consumption of fluids earlier in the cycle phase of the Olympic distance triathlon benefits the run and overall performance time.

Pre-Game Urine Specific Gravity Does Not Predict Fluid Intake by Professional Basketball Players during Competition

2007 ◽  
Vol 39 (Supplement) ◽  
pp. S315
Author(s):  
Kristin L. Osterberg ◽  
Lindsay B. Baker ◽  
Magie Lacambra ◽  
Robert Murray
Keyword(s):  
Specific Gravity ◽  
Fluid Intake ◽  
Urine Specific Gravity ◽  
Basketball Players ◽  
Professional Basketball

scholarly journals Hydration Status in Adolescent Alpine Skiers During a Training Camp

2021 ◽  
Vol 79 (1) ◽  
pp. 55-63
Author(s):  
Dirk Aerenhouts ◽  
Laurent Chapelle ◽  
Peter Clarys ◽  
Evert Zinzen
Keyword(s):  
Specific Gravity ◽  
Fluid Intake ◽  
Training Session ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Fluid Loss ◽  
Individual Values ◽  
Training Camp ◽  
Ad Libitum ◽  
Alpine Skiers

Abstract Maintaining euhydration is important for optimal health, performance and recovery, but can be challenging for alpine skiers when training in a relatively cold but dry environment. This study aimed to evaluate hydration status, fluid loss and fluid intake in adolescent alpine skiers during a training camp. Twelve athletes aged 14.3 ± 0.9 years volunteered to participate in the study. Athletes resided at an altitude of 1600 m and trained between 1614 and 2164 m. During eight consecutive days, urine specific gravity was measured before each morning training session using a refractometer. Changes in body weight representing fluid loss and ad libitum fluid intake during each morning training session were assessed using a precision scale. Mean pre-training urine specific gravity remained stable throughout the training camp. Individual values ranged between 1.010 and 1.028 g/cm3with 50 to 83% of athletes in a hypohydrated state (urine specific gravity ≥ 1.020 g/cm3). Mean training induced fluid loss remained stable throughout the training camp (range -420 to -587 g) with individual losses up to 1197 g (-3.5%). Fluid intake was significantly lower than fluid loss during each training session. To conclude, urine specific gravity values before training indicated insufficient daily fluid intake in more than half of the athletes. Furthermore, fluid intake during training in adolescent alpine skiers was suboptimal even when drinks were provided ad libitum. Coaches and athletes should be encouraged to carefully monitor hydration status and to ensure that alpine skiers drink sufficiently during and in between training sessions.

Urine Specific Gravity as a Practical Marker for Identifying Suboptimal Fluid Intake of Runners ∼12-hr Postexercise

2019 ◽  
Vol 29 (1) ◽  
pp. 32-38
Author(s):  
Eric Kyle O’Neal ◽  
Samantha Louise Johnson ◽  
Brett Alan Davis ◽  
Veronika Pribyslavska ◽  
Mary Caitlin Stevenson-Wilcoxson
Keyword(s):  
Specific Gravity ◽  
Body Mass ◽  
Fluid Intake ◽  
Area Under The Curve ◽  
Fluid Replacement ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Accuracy Score ◽  
Characteristic Area ◽  
Almost All

The legitimacy of urine specific gravity (USG) as a stand-alone measure to detect hydration status has recently been challenged. As an alternative to hydration status, the purpose of this study was to determine the diagnostic capability of using the traditional USG marker of >1.020 to detect insufficient recovery fluid consumption with consideration for moderate versus high sweat losses (2.00–2.99 or >3% body mass, respectively). Adequate recovery fluid intake was operationally defined as ≥100% beverage fluid intake plus food water from one or two meals and a snack. Runners (n = 59) provided 132 samples from five previous investigations in which USG was assessed 10–14 hr after 60–90 min runs in temperate-to-hot environments. Samples were collected after a meal (n = 58) and after waking (n = 74). When sweat losses exceeded 3% body mass (n = 60), the relationship between fluid replacement percentage and USG increased from r = −.55 to −.70. Correct diagnostic decision improved from 66.6 to 83.3%, and receiver operating characteristic area under the curve increased the diagnostic accuracy score from 0.76 to approaching excellent (0.86). Artifacts of significant prerun hyperhydration (eight of 15 samples has USG <1.005) may explain false positive diagnoses, while almost all (84%) cases of false positives were found when sweat losses were <3.0% of body mass. Evidence from this study suggests that euhydrated runners experiencing significant sweat losses who fail to reach adequate recovery fluid intake levels can be identified by USG irrespective of acute meal and fluid intake ∼12-hr postrun.

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