How much sodium do you actually lose in sweat?
Sweat sodium concentration varies roughly 5–10x between athletes. Here's why the number on a generic electrolyte label rarely matches your own.
Ask ten athletes how much sodium they lose per liter of sweat and, if they know at all, you'll get ten different answers — and that's the point. Sweat sodium concentration is highly individual, commonly cited across a range of roughly 200 to 2,000+ mg per liter depending on the person. TODO: cite primary sports-science literature for this range.
Why the variation is so large
Sweat starts as a near-plasma-concentration fluid, then sodium is reabsorbed as it travels through the sweat gland duct. How much gets reabsorbed depends on genetics, heat acclimatization, training status, and sweat rate itself — the faster you sweat, the less time the duct has to reclaim sodium, so higher sweat rate often means saltier sweat.
Why a generic number doesn't work
A sports drink formulated for the population average will under-replace sodium for a heavy, salty sweater and over-replace it for a light one. Neither is trivial: under-replacement is linked to cramping and, in extreme cases, exercise-associated hyponatremia when paired with excess plain water intake. Over-replacement mostly costs you GI comfort and unnecessary sodium load.
- Sweat sodium is commonly measured in mg/L or mmol/L
- It's distinct from — but related to — your total sweat rate
- Both numbers are needed to calculate your actual hourly sodium loss
That's what the Sweatprint™ Test measures directly, rather than estimating from population averages. TODO: link to full methodology / references once finalized.
This is a seed draft written to demonstrate the article template. TODO: fact-check every quantitative claim, add citations, assign a real author, and remove the draft flag before publishing.