Salt during Exercise?
When you exercise for more than three hours, you should
take in salt as well as fluids. A study from Switzerland followed
female competitive distance runners who took in drinks with different
concentration of salt during a four hour run. Ninety-two percent of
those who took in plain water with no additional salt developed low
blood levels of salt, which can be dangerous (British Journal of
Sports Medicine, Volume 37, Issue 4, 2003).
Taking in fluid without also taking in adequate amounts
of salt dilutes the bloodstream, so that the concentration of salt in
the blood is lower than that in brain cells. This causes fluid to
move from the low-salt blood into the higher-salt brain causing
the brain to swell which can cause seizures and death. Taking in
extra salt during prolonged exercise increases thirst so you drink
more fluids, and prevents blood salt levels from dropping so low
that you become tired, develop muscle cramps, and can even
die. Furthermore, without salt you do not recover as quickly and
are more likely to be injured or tired all the time. If you're
concerned about the reports of deaths from over-hydration, read about hyponatremia
Checked 9/29/08