Relative expansion of extracellular water in elite male athletes compared to recreational sportsmen.

Abstract

This study reports total body hydration and water distribution between the extracellular water (ECW) and the intracellular water (ICW) of a group of 15 elite male athletes compared with a group of 15 male subjects practising the same sport at 'amateur' level. Total body water (TBW) and ECW were assessed by means of deuterium and bromide dilution techniques respectively. Both TBW and body hydration were significantly higher in elite athletes than in non-competitive subjects (52.3 +/- 5.0 vs 46.1 +/- 4.2 litres p < 0.001 and 63.2 +/- 1.9 vs 60.2 +/- 1.9% body weight, p < 0.003 respectively). Likewise, both ECW the ratio of ECW to TBW were significantly higher in athletes than in control subjects (20.7 +/- 2.9 vs 16.1 +/- 1.8 litres, p < 0.0001 and 0.40 +/- 0.06 vs 0.35 +/- 0.03, p < 0.005 respectively). ICW was similar in both groups but the ICW to ECW ratio was significantly higher in the athletes compared to the recreational sportsmen (0.67 +/- 0.16 vs 0.54 +/- 0.07, p < 0.01). These data suggest that assumptions regarding the chemical composition of the standard human body may not be valid in elite athletes.