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Multiplies sweat rate, duration and sweat sodium concentration to give the sodium lost during exercise and the concentration needed to replace it.
Sweat sodium loss
Sodium lost (mg) = sweat rate (L/h) x hours x sweat sodium concentration (mg/L); salt (g) = sodium (mg) x 2.542 / 1000
Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
Very. It ranges from about 200 to 2,000 mg per litre between individuals and falls somewhat with heat acclimatisation.
In sessions over about two hours, in heat, and in salty sweaters where hyponatraemia risk rises with plain water intake.