== Salt loss through sweat ==
The amount of salt that is lost through sweating varies a lot. It varies from individual to individual, and for an individual it will vary depending on fitness and heat acclimation <ref name="ref9"/>. This means that you may have to experiment with your salt intake, both during and after exercise. Anecdotal tip: If your skin is crusty with salt after a run, you are probably someone who sweats out a lot of salt.
===Sodium Loss Table==={| {{table}} | align="center" style="background:#f0f0f0;"|'''Source'''| align="center" style="background:#f0f0f0;"|'''Sodium - grams per liter'''| align="center" style="background:#f0f0f0;"|'''Sodium – grams per pint'''| align="center" style="background:#f0f0f0;"|'''Salt – grams per pint'''|-|Blood||6.1||2.9||7.3|-|Sweat of un-acclimated, unfit||3.5||1.7||4.2|-|Sweat of un-acclimated, fit||2.6||1.2||3|-|Sweat of acclimated, fit||1.8||0.9||2.3|-|Gatorade||0.4||0.2||0.5|-|Gatorade+ 1/4 Teaspoon salt per quart||0.9||0.5||1.2|}===Examples===Here are some hypothetical examples * Adam, a fit, heat acclimatized runner, weighs himself before and after his run and the difference is 8 pounds, which is roughly equivalent to 8 pints of sweat. We estimate that Adam has lost 0.9 grams of sodium per pint, for a total of 7.2 grams of sodium, which is 18 grams of salt or about 3 teaspoons. * Bob, a fit, but not heat acclimatized runner, weighs himself before and after his run and the difference is 10 pounds, which is roughly equivalent to 10 pints of sweat. We estimate that Bob has lost 1.2 grams of sodium per pint, for a total of 12 grams of sodium, which is 30 grams of salt or about 5 teaspoons.* Charlie, a fit, but not heat acclimatized runner, weighs himself before and after his run and the difference is 8 pounds, which is roughly equivalent to 8 pints of sweat. Charlie had also consumed 80 ounces of Gatorade on the run. This gives an estimate of 8+5=13 pints of sweat. At 1.2 grams of sodium per pint, that’s a total of 15 grams of sodium, which is 37 grams of salt or about 6 teaspoons. The Gatorade provided approximately 1 gram of sodium, or a 1/2 teaspoon. * For the next run, Charlie changes his drink to add 1/4 teaspoon of extra salt to his Gatorade. He sweats and drinks the same amounts as the previous run. This time, his drink provides him with 4.7 grams of salt, or 3/4 teaspoon of salt.
== More on Hyponatremia ==
Hyponatremia is where the sodium (salt) levels becomes too dilute. Initial symptoms tend to be a gain in weight and a general swelling and 'puffiness', most noticeable in the hands. More severe symptoms are caused by a swelling of the brain (cerebral edema) including nausea, vomiting, headache and malaise <ref name="ref10"/>.