Two athletes can lose wildly different amounts of sodium in the same race. Knowing your number is the difference between cramping and cruising.
Sweat is not just water — it carries sodium, and how much varies enormously between people. “Salty sweaters” can lose more than 1500mg of sodium per litre of sweat; others lose a fraction of that. Replacing the wrong amount is a common, fixable cause of cramp and flat legs.
Signs you are a salty sweater
White salt marks on your kit and cap, stinging eyes, and a gritty taste on your lips after a hard session are all clues that you sit at the higher end of the range and need a stronger electrolyte strategy.
Get tested, then dial it in
A sweat test gives you a precise sodium concentration. From there, match it: lighter sweaters do well on PH 1000 (1000mg/L), while heavy and salty sweaters often need PH 1500 (1500mg/L), especially in heat.
Pre-load before long, hot races
For events over two hours in the heat, drinking a strong electrolyte bottle the night before and the morning of the race tops up your reserves so you start the day already topped up rather than chasing losses.
