O'Dea, N. K., Benardot, D., Cody, M., & Thompson, W. (2010). Gender-specific hydration practices during cold-weather distance running. Presentation 2299 at the 2010 Annual Meeting of the American College of Sports Medicine, Baltimore, Maryland; June 2-5.

This study examined hydration practices and risk factors associated with hyponatremia in non-elite runners participating in a cold weather long-distance races. Pre- and post-race measures were obtained on marathon Ss (M = 14; F = 3) and half-marathon Ss (M = 34; F = 41). Ss completed a survey and pre-race weights at the pre-race Expo and after the half-marathon and marathon competitions under race-day conditions of 4ºC. Post-race weight was measured within five minutes of crossing the finish line.

In the marathon, weight change for all Ss was not significantly different but was different for Ss who took NSAIDs prior to the race compared to those who did not. In the half-marathon, no significant weight change occurred but there was a significant gender difference in weight change between males (~-0.57 kg) compared to females (~+0.73). There was no difference in weight change based on NSAID usage. Fluid consumption frequency was positively but weakly correlated with weight change in half-marathoners (r = 0.36) and in female half-marathoners (r = 0.41). As finishing time increased, weight increased (r = 0.356) in half marathon Ss.

Implication. Females and those using NSAIDs prior to distance running in cold weather may be at greater risk for over-hydration (as measured by weight gain), a contributing factor in hyponatremia.

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