Believe it or not, guzzling too much water could
have negative even deadly consequences. A study published this past
spring in the New England Journal of Medicine found that
13 percent of Boston Marathon runners suffered from hyponatremia,
or low blood sodium caused by drinking too much water. That
condition can cause “race-related death and life-threatening
illness,” according to the study.
Revised guidelines from USA Track & Field suggest starting
an endurance race well-hydrated and not drinking more liquid than
you sweat out. Simplified, USATF says, “Be sensitive to the onset
of thirst as the signal to drink, rather than staying ahead of
thirst.” Most at risk are women and beginning runners who can be
slower and therefore spend more time running.
For travelers involved in their own tests of endurance such as
a long hike on a hot day or a grueling bike ride the advice is
similar. Instead of chugging water, try moderate amounts of a
sports drink containing electrolytes, and have a salty snack, such
as pretzels, along the way.