Electrolytes After Sauna: Do You Need Them, and When?

Most sauna advice is wrong in one of two directions. Either "you don't need anything but water," or "buy our sauna electrolytes for every session." The truth is in between, and it depends on how hard you go.

Here's the no-nonsense version: when you need electrolytes after sauna, when you don't, and what you should never be drinking out of a hot room.

What sweat takes with it

Sweat is mostly water, but it carries sodium out with it, along with smaller amounts of other minerals. How much you lose varies a lot between people. Salty sweaters, the ones with white streaks on their hats and sweat that stings their eyes, lose more. Longer, hotter sessions take more. Training right before you sit takes more.

That's why the American College of Sports Medicine guidance, as summarized in a study on heat exercise published in the Journal of Athletic Training, says that when sweating is heavy, special attention should go to replacing sodium, through a sodium-containing drink or salty food with enough fluid.

Do you need electrolytes after a sauna?

Not after every session. A short, moderate sauna followed by a normal salted meal? Water is fine. Your food brings the sodium.

Where electrolytes after sauna actually matter:

• Long or repeated rounds
• Sauna right after a hard workout
• Hot days, or a full contrast circuit
• Heavy, salty sweaters

That's true for traditional and infrared sauna alike.

Electrolytes before or after sauna?

After is the money move, because that's when you're replacing what you lost. Before matters most if you trained earlier, you're already depleted or you're planning a long session. A lot of regulars do water before and electrolytes after.

The worst things to drink after sauna

Alcohol

Heat and alcohol work against you. Alcohol pushes you to lose more fluid, according to NIAAA, which explains that it suppresses vasopressin, the hormone that helps your kidneys hold water. Save it for never, or at least for much later.

Sugar bombs

You just sat in a hot room. You're not fueling a marathon. You don't need a sugar-based sports drink to rehydrate from that.

The "clean" sweetener stack

A lot of sugar free hydration drinks swap sugar for a stack of stuff you didn't ask for:

• Manufactured citric acid, mostly made by fermenting sugar with the black mold Aspergillus niger, per a 2018 Toxicology Reports paper that also described four people with repeated inflammatory reactions to it. Small case report, not proof of harm.
• "Natural" flavors, which under 21 CFR 101.22 can be declared without listing the incidental additives that come with them.
• Sucralose, whose impurity sucralose-6-acetate tested genotoxic in 2023 lab screening assays. In vitro findings, with the authors flagging serious concerns.
• Erythritol, associated with higher cardiovascular event risk in a 2023 Nature Medicine study of cardiac patients. Association, not proven cause.

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How to rehydrate after sauna

1. Water plus sodium. An electrolyte drink, broth, or water with a salty snack.
2. Sip over the next hour. Don't chug.
3. Eat a salted meal after long or repeated sessions.
4. Cool down gradually if you're skipping the plunge.

How much water to drink after sauna

Weigh yourself right before and right after, wearing the same thing or nothing. The difference is mostly fluid. Do it a few times and you'll know your own number instead of guessing.

What to drink after sauna

Water and sodium. That's the whole answer. Our version of it:

PRØTOCOL per serving:

• 500 mg sodium, 300 mg potassium, 100 mg magnesium
• 0 g added sugar, sweetened with organic monk fruit extract
• Organic lemon and lime juice powder
• No added citric acid, no "natural" flavors, no maltodextrin, no artificial colors
• USDA Organic, non-GMO, gluten free, vegan

One stick in 8 to 12 oz of cold water. Bright, salty, citrus, done.

Before your session

• Show up hydrated. Starting dry is the most common mistake.
• Trained today? One stick 30 to 60 minutes before.
• No alcohol.
• Eat light.

During your session

• Water within reach. Sip between rounds.
• Dizzy, nauseous, pounding heart? You're done. Get out, sit somewhere cool, drink.
• It's not a contest.
• New to sauna? Start short and build over weeks.

Contrast therapy: sauna plus cold plunge

Same rules, more rounds. Hydrate before, sip between, finish with electrolytes. Hot to cold changes things fast, so get in and out of the plunge carefully, and don't do it alone if you're new.

Safety first

Talk to your doctor before using a sauna if you're pregnant, have heart disease, high or low blood pressure or a history of fainting, or take medications that affect blood pressure, heart rate or fluid balance. Never sauna after drinking.

The bottom line

You don't need electrolytes after every sauna. You do need them after long, hot, repeated or post-workout sessions, and when you do, you should be drinking real sodium, not a sweetener stack. Keep a few sticks in your gym bag before your next session.

Sources

1. Anastasiou CA, et al. "Sodium replacement and plasma sodium drop during exercise in the heat when fluid intake matches fluid loss." J Athletic Training, 2009. https://pmc.ncbi.nlm.nih.gov/articles/PMC2657026/
2. NIAAA, "Hangovers." https://www.niaaa.nih.gov/publications/brochures-and-fact-sheets/hangovers
3. Sweis IE, Cressey BC. "Potential role of the common food additive manufactured citric acid in eliciting significant inflammatory reactions contributing to serious disease states: A series of four case reports." Toxicology Reports, 2018. https://pmc.ncbi.nlm.nih.gov/articles/PMC6097542/
4. 21 CFR 101.22, labeling of spices, flavorings, colorings and chemical preservatives (natural flavor definition, (a)(3); incidental additives in flavors, (h)(2)). https://www.law.cornell.edu/cfr/text/21/101.22
5. Schiffman SS, et al. "Toxicological and pharmacokinetic properties of sucralose-6-acetate and its parent sucralose: in vitro screening assays." J Toxicol Environ Health B, 2023. https://www.tandfonline.com/doi/full/10.1080/10937404.2023.2213903
6. Witkowski M, et al. "The artificial sweetener erythritol and cardiovascular event risk." Nature Medicine, 2023. https://www.nature.com/articles/s41591-023-02223-9
7. PRØTOCOL label. https://protocoldrink.com/label