How Much Water Should You Drink in a Sauna? Hydration Guide

How Much Water Should You Drink in a Sauna? Hydration Guide

You're going to sweat. A lot. The average person loses between 1 and 2 pints of sweat during a 15-20 minute sauna session. At higher temperatures or longer durations, you can easily lose a quart or more.

That fluid has to come from somewhere, and if you don't replace it, you'll feel it. Here's exactly how much to drink and when.

Before the Sauna

Drink 16-24 ounces of water in the 1-2 hours leading up to your sauna session. Don't chug it all at once right before you go in - that'll just leave you feeling bloated and sloshy. Spread it out. Sip steadily.

If your urine is pale yellow before you enter the sauna, you're in good shape. Dark yellow means you're already behind on hydration and should drink more before stepping in.

During the Sauna

Bring water into the sauna with you or keep it just outside the door. Take small sips between rounds. About 8-12 ounces per 15-minute session is a reasonable target, though you may need more if you're running the sauna hot or doing multiple rounds.

Don't force yourself to drink large amounts at once. Small, frequent sips are absorbed better than dumping 20 ounces into an empty stomach.

Some people prefer to avoid drinking during their actual sauna session and only hydrate between rounds. That's fine for shorter sessions. For anything over 15 minutes, having water available is important.

After the Sauna

This is where most people under-hydrate. After your session, drink at least 16-24 ounces over the next 30-60 minutes. Your body continues to sweat and cool itself even after you leave the sauna, so fluid loss doesn't stop the moment you step out.

A good rule of thumb: replace 1.5 times what you lost. If you weigh yourself before and after a sauna session (try it once - it's eye-opening), the weight difference is almost entirely water. For every pound lost, drink about 24 ounces to fully replenish.

Total Daily Hydration for Sauna Users

If you sauna regularly, you need more daily water intake than someone who doesn't. The standard "8 glasses a day" recommendation doesn't account for significant sweat loss. Add an extra 32-48 ounces on sauna days on top of your normal intake.

Most regular sauna users find that drinking 80-120 ounces of water throughout the day keeps them well-hydrated. But this varies by body weight, climate, activity level, and how intensely you sauna.

Why Electrolytes Matter

Water alone isn't enough if you're a heavy sweater or sauna frequently. When you sweat, you lose more than just water. You lose sodium, potassium, magnesium, and other electrolytes that your muscles and nerves need to function.

Signs you need electrolytes, not just water:

• Muscle cramps during or after sauna
• Headache that doesn't go away even after drinking water
• Feeling tired or foggy despite being hydrated
• Lightheadedness when standing up

Easy ways to add electrolytes:

• A pinch of sea salt and squeeze of lemon in your water
• Electrolyte tablets or powders (LMNT, Liquid IV, Nuun, etc.)
• Coconut water (natural electrolytes)
• A small salty snack after your session

Skip sports drinks loaded with sugar. You want the minerals, not 40 grams of high-fructose corn syrup.

What NOT to Drink

• Alcohol: Dehydrates you, impairs heat regulation, and increases the risk of dangerous drops in blood pressure. Never drink alcohol before or during a sauna session. Check our article on sauna and alcohol for more details.
• Coffee right before: Caffeine is a mild diuretic. One coffee a couple hours before is fine, but don't chug an espresso right before stepping in.
• Sugary drinks: Soda, juice, and sweetened sports drinks can cause blood sugar spikes and crashes that make you feel worse in the heat.
• Ice-cold water during the session: Extremely cold water can shock your system when you're overheated. Room temperature or slightly cool water is better during the session. Save the cold drink for after.

Signs You're Dehydrated

Know these warning signs and exit the sauna immediately if you notice them:

• Dizziness or lightheadedness
• Headache
• Nausea
• Rapid heartbeat that doesn't settle
• Dry mouth and extreme thirst
• Confusion or difficulty concentrating
• Stopping sweating (this is serious - your body has run out of fluid to sweat)

If you stop sweating in a hot sauna, get out immediately, drink water with electrolytes, and cool down. This is your body telling you it's running dry.

Quick Hydration Cheat Sheet

• 1-2 hours before: 16-24 oz water
• During (per 15-min round): 8-12 oz water
• After: 16-24 oz water with electrolytes
• On sauna days: Add 32-48 oz to your normal daily intake

Hydration is the simplest thing you can do to have better, safer, longer sauna sessions. Keep a water bottle with you, add some electrolytes, and drink steadily throughout the day.

Looking for the right setup for your home? Browse our outdoor saunas and sauna accessories to build your perfect sauna experience.