Sauna hydration, Ireland
Electrolytes for sauna · Ireland
You sweat like an athlete in there. You rehydrate like someone who forgot.
A hard sauna session pulls out more fluid and salt than most gym workouts, and plain water puts back only part of it. Set up your session below and we'll show you what you actually lost, and which electrolyte on the market replaces it.
temperature
- Fluid out
- 1.1L
- Sodium out
- 1025mg
- Time hot
- 41min
- Water alone replaces
- 0% of the salt
Nothing above was made for sauna
Every one is a good product built for a different problem — LMNT for endurance athletes, Precision for cyclists counting grams, Liquid I.V. leading with sugar and 13 g of carbs a stick to rehydrate you fast mid-effort. None was dosed for four rounds at 95 degrees.
Search for sauna electrolytes and you get running products with a sauna photo. So we're making the one that isn't: mixed for what heat actually takes out of you, with Irish Atlantic sea salt and nothing you don't need. Join the waitlist.
Check any of them against your session
Pick a product and see what one serving actually gives you back, against what this session cost you. Replacing every milligram is not the goal, most people make up the rest from food. This is about seeing where each one lands.
When to drink it
Why salt, not just water
Sauna sweat is real sweat
Heat sweat carries sodium at roughly the same concentration as exercise sweat, around 500 to 1,500 mg per litre depending on the person. Sitting still doesn't give you a discount.
Water replaces volume, not salt
After a hard session, sinking litres of plain water tops up fluid while the salt you lost stays missing. That matters most on long or back-to-back sessions. The light head when you stand up, though, is usually blood pressure rather than sodium. Heat widens your blood vessels, and it passes.
Regulars sweat differently
Get used to the heat and your body starts conserving salt. An acclimatised bather's sweat can carry a fraction of the sodium of someone going twice a year. That's why we ask how often you go, and it's why one number for everyone would be wrong.
Sports tabs are built for a different job
Most tablets sit near 300 mg of sodium per serving, tuned for a bottle you sip over an hour of running. After four hard rounds in the heat the arithmetic doesn't reach.
How we work this out
The fluid estimate
Built from your session type, the number of rounds and the temperature, anchored to published sauna sweat rates of roughly 0.6 to 1.0 kg an hour at 80 to 90 degrees, with steam rounds at the upper end and a typical session averaging about half a kilo.
The sodium estimate
Fluid loss multiplied by a sweat sodium concentration of 1,400, 1,100 or 800 mg per litre depending on how often you bathe. Real values vary widely between people, anywhere from 500 to 1,500 mg per litre, so treat these as estimates, not measurements.
And whether you need any of it
Most people replace a normal session's salt from food without thinking about it. Topping up matters most on long or back-to-back sessions, if you sweat heavily, if you already eat low-salt, or if you finish sessions with a headache or cramps.
Where the figures come from
Three published sources sit under the numbers above.
- Sweat rates — Laukkanen, Laukkanen & Kunutsor, Cardiovascular and Other Health Benefits of Sauna Bathing: A Review of the Evidence, Mayo Clinic Proceedings, 2018. The standard review of sauna physiology. Sauna sweating is generally put at roughly 0.6 to 1.0 kg an hour at 80 to 90 degrees, the range our fluid estimate uses. Read the paper →
- Sweat sodium — Allan & Wilson, Influence of Acclimatisation on Sweat Sodium Concentration, Journal of Applied Physiology, 1971. Sweat sodium runs high in people new to the heat, around 1,400 mg per litre, and falls as the body adapts to regular exposure — a finding replicated many times since. That adaptation is why our estimate drops the more often you bathe, rather than using one number for everyone. Read the paper →
- Sauna vs. exercise sweat — Verde, Shephard, Corey & Moore, Sweat composition in exercise and in heat, Journal of Applied Physiology, 1982. Eight men sampled across outdoor exercise, indoor exercise and sauna: magnesium and calcium ran higher in sauna sweat, while sodium, potassium and chloride were similar throughout. Their own conclusion is worth repeating — total ionic losses did not appear sufficient to deplete body mineral reserves, short of many days training in a hot climate. Read the paper →
Waitlist and hydration card
Leave your email and we'll send you the sauna hydration card, a printable page with what a session costs you and what puts it back. We'll also tell you first when SaunaLyte is ready, and ask what you make of it before it's finished. No spam, no more than a mail a month, and you can leave any time.