Marathon Runners' Knowledge and Strategies for Hydration.

OBJECTIVE

To study hydration plans and understanding of exercise-associated hyponatremia (EAH) among current marathon runners.

DESIGN

Cross-sectional study.

SETTING

Southern California 2018 summer marathon.

PARTICIPANTS

Two hundred ten marathon runners.

INTERVENTIONS

Survey administered 1 to 2 days before the race. Race times were obtained from public race website.

MAIN OUTCOME MEASURES

Planned frequency of hydration; awareness of, understanding of, and preventative strategies for dehydration and EAH; resources used to create hydration plans; drink preferences.

RESULTS

When the participants were split into 3 equal groups by racing speed, the slower tertile intended to drink at every mile/station (60%), whereas the faster tertile preferred to drink every other mile or less often (60%), although not statistically significant. Most runners (84%) claimed awareness of EAH, but only 32% could list a symptom of the condition. Both experienced marathoners and the faster tertile significantly had greater understanding of hyponatremia compared with first-time marathoners and the slower tertile, respectively. Less than 5% of marathoners offered "drink to thirst" as a prevention strategy for dehydration or EAH.

CONCLUSION

Slower runners plan to drink larger volumes compared with their faster counterparts. Both slower and first-time marathoners significantly lacked understanding of EAH. These groups have plans and knowledge that may put them at higher risk for developing EAH. Most marathon runners did not know of the guidelines to "drink to thirst," suggesting the 2015 EAH Consensus statement may not have had the desired impact.