Dose it right for your body and your sport.
Everything SweatSciences knows, organized two ways: by the sport you're doing and by the question you came with. All cited, all pointing back to the one thing that matters — your number, not a label's.
Get your number →By your sport
Same body, different demands — duration, heat, and how you carry fluid change the math.
Marathon
26.2 miles fails in both directions: under-replace sodium and fade, or over-drink and risk hyponatremia.
Marathon hydration →Cycling
Wind evaporates your sweat so you never feel it — and easy bottles make over-drinking the mirror risk.
Long-ride hydration →HYROX
60–90 minutes at threshold in a hot hall — a sodium event where under-replacing, not over-drinking, is the danger.
HYROX electrolytes →Hot yoga, Pilates & sculpt
A calm-feeling class that drives endurance-race losses in a 105°F room. Same math whatever the sign says.
Hot-class hydration →Sauna
Pure-heat sweat — honestly mostly a rehydration job for one session, more for a daily habit.
Sauna electrolytes →Distance running
Race-week hydration and the metabolic science of endurance, built with a distance runner.
Distance & metabolism →Pickleball
Feels easy point to point, but it's hours in the sun, game after game — and many players are older and on meds.
Court hydration →Heat training
Repeated heat may build blood like altitude — and fluid management is what makes it adaptation, not strain.
Heat blocks, honestly →CrossFit
You leave a puddle so you drink — but the gap is usually sodium, not water. Intensity, not duration.
Box hydration →Tennis
The sport cramping is famous in: a hot three-hour match drains more sodium than changeover water replaces.
Court hydration →Spin / indoor cycling
A hot room with no wind — you soak a 45-minute class and feel it, closer to hot yoga than a road ride.
Studio hydration →Hiking
Hours in the sun with a pack; losses stack all day, and both under-salting and over-drinking bite.
Trail hydration →Golf
Four to five hours in the sun; the back-nine fade is usually a hydration gap, not your swing.
Round hydration →By your question
The problems people actually arrive with — answered straight, with the primary sources.
How do I measure my sweat rate?
One before-and-after weigh-in beats any wearable's calorie-based guess. Here's the method.
Measure it →Why do I keep cramping?
Usually a sodium-and-fluid math problem, not a mystery — and how to close the gap.
Fix cramps →Can you drink too much water?
Yes — over-drinking dilutes blood sodium, and on a long day it's more dangerous than dehydration.
The overdrinking risk →How much sodium is in my sweat?
The real numbers — and why two people in the same session can differ tenfold.
Real numbers →Do I need electrolytes on keto?
Keto flu is usually electrolyte depletion, not carb withdrawal — the honest amounts to add.
Keto electrolytes →Why salt, not just water?
The OVLT salt sensor, SGLT1 absorption, and the sodium-potassium ratio, in plain language.
The physiology →Compare, then build
Once you know your number, hit it for a fraction of the pre-mixed price.
Every product, milligram by milligram
LMNT, Nuun, Liquid I.V., Gatorade and the raw minerals — elemental mg and real cost, side by side.
The database →LMNT vs making your own
A fixed 1,000 mg stick vs your tenfold-variable sweat — when it's worth it, and the pennies alternative.
The honest comparison →Make your own, dosed to you
The full real-food-plus-bulk-minerals recipe at your ratio, about $2 a session.
The recipe →The Jar Kit
A jar sized for a month at your ratio, a calibrated scoop, and a printed card. Minerals stay sealed from their brands.
The Kit →For studios & gyms
Host a Sweat Station: a scale and QR so members get their number after class.
The Sweat Station →For teams & coaches
Give every athlete their own number; run a team sweat-test day. Built with a distance runner.
SweatSciences for teams →Notes
Your physiology is not the product — essays on tenfold sweat sodium, DIY vs $200 tests, readiness as a tracer (not a grade), and why the calculator doesn't sell tabs.
Read Notes →What SweatSciences is
The thesis, and an honest account of how a brand-neutral calculator makes money.
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