We can read here that the Yanomamo Indians do fine on a diet that hardly contains any salt. They live in hot humid conditions so they'll certainly lose liquids in the form of sweat of the order of 1 liter or more, yet their sodium intake measured via urinary excretion is around 0.05 grams per day. It has been argued that this level of intake is optimal for us as our bodies have evolved under conditions where there was hardly any salt available. A typical "low salt" Western diet where you take care to avoid excessive salt intake, will typically yield salt intakes that are 50 times higher than a prehistoric diet.
The Yanomamo have blood pressures that are lower than seen in healthy Western people, and blood pressures don't rise with age, as pointed out here. So, it could be that a "normal" blood pressure of 120 mm Hg is actually a hypertensive blood pressure. If this is true then it seems to me that getting rid of salt in the diet, reducing it to something of the order of 0.1 grams or less per day, could not only prevent essential hypertension as we age, but it could be used by athletes as a way to enhance performance.
So, I was wondering if tests have been performed to see if long term severe salt restriction enhances athletic performance?