Hydrating myth - NSCA March 08

Do We Need to Drink Eight Glasses of Water a Day?

... (1). Maintaining proper hydration is necessary for optimal physiologic function
and for athletes it is crucial for optimal athletic performance
(2). The authors determined that this “medical
myth” probably originated around 1945 and later
gained acceptance after receiving an endorsement by a
well known nutritionist (4). Despite the universal acceptance
of this assumption, the authors reported that
there is no evidence in the medical literature to support
this claim (4). As to what one should drink and how
much one should consume each day to maintain hydration,
Vreeman et al (4) wrote the following: “existing
studies suggest that adequate fluid intake is usually met
through typical daily consumption of juice, milk, and
even caffeinated drinks. But drinking excess amounts of
water can be dangerous, resulting in water intoxication,
hyponatremia, and even death” (4).
The manner in how the media reported this article (and
especially the two previously quoted sentences) requires
further review. Based solely upon those two sentences
(and the subsequent media reports) an athlete may
avoid properly rehydrating after an event fearing that
drinking water might seriously affect one’s health (4).
Unfortunately, Vreeman et al’s (4) article provides limited
practical information for individuals, let alone athletes.
The purpose of this article is to present the risks
associated with improper rehydration and an evidence
supported rehydration strategy.
Hyponatremia:
Incidence and Risks
Hyponatremia is a potentially serious condition that
if left untreated can have deadly implications for an
athlete. Hyponatremia is the result of significant electrolyte
loss (through sweating) and consuming too
much water during or after exercise (2). Symptoms associated
with hyponatremia include nausea, malaise,
headache, and vomiting (2). If the condition progresses,
the athlete may experience confusion, seizures, become
unconscious, stop breathing, or experience a heart attack
(2). Fortunately, the risk of developing hyponatremia
is low. One study found that only 0.6% of all
marathoners developed a severe form of hyponatremia
(4).
Tips to Prevent Hyponatremia
Landry et al (3) recommends that one should drink 16
oz of fluid for every one pound of weight that is lost
while exercising. Landry et al (3) also suggest that it is
acceptable for athletes to drink water in order to rehydrate.
Sports drinks that contain electrolytes are also
considered acceptable for rehydrating after sports (and
in some cases may be preferable over water) (3).
Conclusion
Drinking water during and after exercise is safe to consume
when rehydrating. Athletes, working with their
coaches, may consider other drinks to consume in order
to maintain hydration. If an athlete experiences any
symptoms after exercising that are indicative of hyponatremia,
that individual should receive medical attention
immediately.