i used to sweat like a pig but then i usedto always eat loads of salty potato chips!
now i see it lol
i'm adding potassium chloride to my salt anyhow
it must be the water though surely? common thing between madeira and costa rica = islands...
i think possibly larger land masses the main water supply has more sodium and potassium in it
it may only be like 20% difference but if you don't know it kicks your arse