Discover how much water you need to stay hydrated in the sauna and learn the ideal intake for optimal wellness so you can enjoy your sauna experience.

Contrast therapy sessions can be a powerful tool for recovery, relaxation, and performance enhancement, but the intense heat and heavy sweating that come with it can take a toll on your hydration levels.

And you don't want to undo the very benefits you’re seeking.

Whether you’re using the sauna to wind down after a grueling workout, prepare your body for a cold plunge, or boost your endurance, understanding how to hydrate effectively is essential. How much water should you drink to sustain proper fluid intake, maintain peak performance, and get the most out of your sauna time? Let’s dive in.

Understanding sauna-induced dehydration

Sweating is your body’s natural cooling system, and time spent in a sauna takes this process into overdrive. According to Dr. Susanna Søberg, a sauna session lasting 15–20 minutes can lead to the loss of about 22 ounces of fluid.

This dehydration can increase intestinal permeability, impair cognitive function, and cause muscle fatigue or cramping.

Not to mention our brains, composed of approximately 73% water, are particularly vulnerable to dehydration, which can negatively affect memory and decision-making. Beyond the brain, dehydration can strain muscles and limit physical performance, emphasizing the importance of hydration for sauna goers before, during, and after sauna use.

How fluids are lost in the sauna sessions

The primary culprit behind fluid loss in a sauna is sweating, driven by the elevated body temperature. Think of your body as a finely tuned engine—when it heats up, it burns through not just fuel (water) but also essential fluids and lubricants (electrolytes like sodium, potassium, and magnesium) that keep everything running smoothly. Replenishing water alone is like adding gas to a car without checking the oil—it’s not enough to fully restore balance.

On average, a person may lose a pint of fluid during a 20-minute sauna session, but variables like body weight, session duration, and sauna type (infrared vs. traditional or dry saunas like the ones at Framework) can increase this amount, making electrolyte replenishment even more critical.

What are the risks of inadequate hydration?

Failure to hydrate adequately can lead to:

Headaches and exhaustion.
Muscle cramps and impaired exercise performance.
More serious issues like kidney stones or chronic fatigue over time.

These risks underscore why hydration is a non-negotiable aspect of sauna use.

Pre-sauna preparation for proper hydration

Proper preparation can make or break your sauna visit.

Avoid heavy meals before your session, as they can interfere with relaxation and cause discomfort—light, fresh meals that provide energy without burdening your digestive system are the way to go.

A small bowl of unsweetened Greek yogurt topped with fresh berries and a drizzle of honey offers protein, vitamins, and a touch of natural sweetness. Mashed avocado with a sprinkle of sea salt on whole-grain toast or a small portion of quinoa mixed with diced cucumber, parsley, and a splash of lemon juice, or a banana topped with a thin layer of almond or peanut butter offers quick, easily digestible energy.

Hydration strategies for sauna sessions

To offset the water and electrolyte losses, aim to increase your daily fluid intake by 30–50%. For many, this means drinking 135 ounces or more on sauna days.

When to drink water

Before: Drink at least 1-2 glasses of water before entering the sauna to prepare your body for the heat. This initial hydration sets the stage for a good sauna session.
During: Bring a 32-ounce water bottle to your sauna session to keep near the room. Dip out to sip and refill regularly or use our cups. Avoid pouring water over your head—it can interfere with your body’s natural cooling mechanisms.
After: Drink water immediately after the session and continue throughout the day to replenish lost fluids and electrolytes (which, if you’re looking for electrolyte help, we offer them at Framework).

Pay attention to your body’s thirst signals—they’re like your body’s dashboard alerts, signaling when it’s time to refuel. Feeling thirsty is your body’s way of telling you it’s already started to lose fluids, so don’t ignore it, especially during or after a sauna session.

Rehydration isn’t a one-time task that’s solved with a single glass of water; it’s an ongoing process that requires consistent effort throughout the day. Just as a marathon runner wouldn’t rely on a single water station to get through a race, your body needs a steady intake of fluids and electrolytes to recover from the intense heat and sweating of a sauna.

By regularly sipping water and replenishing lost electrolytes, you ensure your body stays in balance, helping you maintain peak performance, focus, and overall health.

The goal is to stay ahead of dehydration—not play catch-up after the fact.

What to drink for rehydration

Not all fluids are created equal.* The best beverages for rehydration during sauna use include:

Clear drinking water: A universal staple for hydration.
Mineral water: Replenishes essential minerals lost during sweating.
Coconut water: A natural source of electrolytes like potassium.

*Avoid purified water without minerals, as it lacks the compounds needed for effective hydration.

Electrolyte balance after sauna use

Electrolytes—sodium, potassium, magnesium, and calcium—are crucial for rehydration. For regular sauna users, electrolyte supplements can be a convenient option to maintain balance. Since sodium loss is particularly high during intense sweating, consider incorporating a pinch of salt into your water, consuming salty snacks post-session, or using an electrolyte packet like the ones offered at the studio.

Blend together frozen fruits, spinach, and coconut water for a hydration-friendly smoothie bowl. Use a whole-grain wrap spread with hummus and filled with spinach, shredded carrots, and sliced bell peppers for a nutrient-packed post-sweat snack. Or prepare a bed of mixed greens topped with grilled salmon, avocado, and a light vinaigrette for your recovery-fix of protein and healthy fats.

Here are a few quick tips to keep your hydration top-of-mind once you leave the studio:

Continued hydration: Continue to drink water throughout the day to replenish lost fluids. Consistent hydration is crucial for recovery and maintaining overall health.
Electrolyte replenishment: Consider adding electrolyte-rich beverages or supplements to your routine to help replenish lost electrolytes. This is especially important if you sauna regularly.
Avoid dehydrating drinks: Avoid drinking caffeinated or carbonated beverages, as these can exacerbate dehydration. Stick to water, herbal teas, or electrolyte drinks.
Incorporate hydrating foods: Fruits, vegetables, and broth-based soups to help replenish lost fluids and electrolytes. Foods like watermelon, cucumbers, and oranges are excellent choices.

Maximizing the health benefits of traditional sauna sessions at Framework.

Saunas offer a host of health benefits—from improved cardiovascular function to stress relief—making them a compelling, cornerstone addition to any fitness routine. But the key to unlocking the full benefits of sauna use lies in proper hydration. When you prepare thoughtfully, your body reaps the full rewards of the sauna’s transformative effects—better health, more energy, and a greater sense of well-being.

Balance your fluid intake throughout the day, and listen to your body’s needs before, during, and after each session. Drink smart, drink plenty, sweat it out, and repeat to build the foundation for your health.

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