Fluid Balance, Hydration Status, and Sweat Electrolyte Concentrations in NBA Basketball Players During Pre-Season Practice

Abstract

1236 Very little is known about the effects of two-a-day training on the hydration of professional basketball players. PURPOSE: To determine fluid intake habits and hydration status of NBA players, we observed four players on two separate occasions spaced two weeks apart. METHODS: The first observation day was during a preseason two-a-day practice. A urine sample was collected prior to each practice to determine urine specific gravity (USG). Players were weighed before and after practice as were bottles containing their choice of beverage. Sweat loss, percent dehydration, and fluid intake were calculated from these measurements. Sweat patches were placed on the right forearm during each practice to obtain sweat samples and were analyzed to measure sodium and potassium concentrations (flame photometry). Additionally, skin fold measurements were obtained. The same measurements were taken two weeks later to detect any changes that may have occurred due to training and acclimation. RESULTS: Average height, weight and percent body fat were 193.0 cm, 101.4 kg, and 14%, respectively. Sweat rates were modest, with an average of 0.85 liters per hour. Dehydration ranged from 0–1.5% of body weight. The range for USG was1.011 – 1.035 g/ml. The majority of samples (56%) were above 1.030, indicating the players were hypohydrated prior to the start of practice. Sweat sodium and potassium concentrations were within the normal range for all players (44.2 – 86.6 mEq Na/L and 3.6 – 6.3 mEq K/L, respectively) on the first practice day. Sweat samples were obtained on two of the four players during the second visit two weeks later. While potassium concentration remained constant, sweat sodium concentration decreased markedly (56 and 44 mEq/L to 27 and 29 mEq/L). CONCLUSIONS: The NBA players appeared to be inadequately hydrated prior to the start of practice. Based on USG, even if players restored their initial, pre-practice morning body weight, the players were hypohyrated when they returned for the second session. This limited sample suggests players need to be more proactive with rehydration strategies.