Pregame urine specific gravity and fluid intake by National Basketball Association players during competition.
BACKGROUND
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.


METHODS
Cross-sectional study.


METHODS
Basketball players were monitored during Summer League competition.


METHODS
Players (n = 29) from 5 teams of the National Basketball Association agreed to participate.


METHODS
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.
Osterberg
Kristin L
KL
Gatorade Sports Science Institute, 617 West Main Street, Barrington, IL 60010, USA. Kris.Osterberg@Gatorade.com
Horswill
Craig A
CA
Baker
Lindsay B
LB
D000293:Adolescent; D000328:Adult; D001490:Basketball / Q000502:physiology*; D003163:Competitive Behavior; D003430:Cross-Sectional Studies; D003681:Dehydration / Q000209:etiology / Q000517:prevention & control*; D004326:Drinking / Q000502:physiology*; D004573:Electrolytes / Q000032:analysis; D005440:Fluid Therapy; D006304:Health Status; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D013046:Specific Gravity; D013542:Sweat / Q000737:chemistry; D013997:Time Factors; D014481:United States; D014556:Urine / Q000737:chemistry*; D014870:Water Loss, Insensible; D014882:Water-Electrolyte Balance / Q000502:physiology; D055815:Young Adult
D004573:Electrolytes