Walking into a sauna feels like stepping into a warm, heavy blanket. The air is incredibly hot, and within just a few minutes, your body starts to sweat from head to toe. People all over the world use these hot wooden rooms to relax their tired muscles, warm up on a cold winter day and feel calm after a long week of hard work.
But because the room is so incredibly hot, many people wonder exactly how much time is safe to spend inside. You might see some people sitting in the heat for a very long time and wonder if you should do the same.
Overview
You should only stay in a sauna for 15 to 20 minutes at a time. If you are a complete beginner and have never been in a hot room before, you should stay inside for only five to 10 minutes, Healthline explains. The heat in a sauna puts a lot of stress on your body. It makes your heart beat much faster and causes you to lose a massive amount of water through your sweat. Staying in intense heat for more than 20 minutes can easily make you feel dizzy, sick to your stomach or even faint. Knowing how to time your visit properly keeps you perfectly safe while you relax.
Step 1: Start slow and short
If it is your very first time trying a sauna, you must treat it like trying a brand-new sport. You would not run a marathon on your first day of running. In the same way, you should not sit in a hot room for 20 minutes on your first try.
Your body is not used to breathing in hot air or sweating that fast. For your first visit, set a timer for just five to 10 minutes. Sit on the bottom bench, where the air is a little cooler than near the ceiling. When your timer goes off, stand up slowly and walk out of the room. It is perfectly fine if you do not sweat very much on your first day. Your goal is to let your body feel the heat and learn how to handle it safely.
Step 2: Listen to your body’s alarms
When you are inside the hot room, your body will constantly talk to you. You must pay very close attention to how you feel. Do not watch the clock; watch your body.
According to the Mayo Clinic, heat causes the blood vessels in your skin to dilate, lowering your blood pressure and making your heart work much harder. If your heart starts pounding incredibly fast, like you are running a race, that is an alarm.
If you suddenly feel dizzy, if your head starts to hurt, or if you feel like you might throw up, you must leave the room immediately. Never force yourself to stay inside just because your timer has not gone off yet. Leaving early is the smartest and safest thing you can do.
Step 3: Gradually add more time
Once you have visited the sauna a few times and feel very comfortable with 10 minutes, you can slowly start to add more time.
The next time you go, try staying for 12 minutes. If you feel great, try 15 minutes on your next visit. You can gradually build up to the maximum recommended time of 20 minutes. You can also try moving from the bottom bench to the top bench, where the heat is much stronger. Just remember that every single day is different. If you are very tired or did not drink enough water that morning, you might only be able to stay for 10 minutes, even if you normally stay for 20.
Best sauna practices
Using a sauna safely requires a little planning before you even set foot inside the hot room. Following a few simple rules will make your visit much more enjoyable.
Stay hydrated
Hydration isn’t just a suggestion; it is the absolute golden rule of heat safety. Before stepping into a high-temperature environment – whether it’s a sauna, a steam room or a grueling hot yoga session – you must prime your system by drinking a very large glass of plain water.
When you enter extreme heat, your body’s internal cooling system kicks into overdrive, triggering profuse sweating. To maintain this essential process without your blood pressure dropping or your heart racing, your body requires a pre-loaded reservoir of fluids. Without this “buffer,” you risk rapid dehydration before you even realize you’re thirsty.
It is equally vital to avoid beer, wine or spirits before exposing yourself to the heat. Alcohol is a diuretic, meaning it actively signals your kidneys to flush water out of your system. This “drying out” effect, combined with the fluid loss from sweating, is a recipe for disaster. In a confined, hot space, losing your balance or fainting can lead to serious injury.
Don’t go in with a full stomach
You should avoid eating a giant, heavy meal right before you sit in the heat. When you eat a big meal, your body sends a lot of blood to your stomach to help digest the food. When you are in a sauna, your body also redirects blood to your skin to cool you down. Doing both at the same time will make your stomach feel terrible and cause severe cramps. Wait at least one hour after eating before you go in.
If you are trying a sauna for the very first time, it is always a good idea to bring a friend. If you suddenly feel dizzy or weak from the extreme heat, having a friend sitting right next to you ensures that someone can help you open the heavy wooden door and safely walk you out to the cool air.
What do you do after a sauna?
When you finally step out of the hot room, your body needs time to get back to normal. The very first thing you should do is drink another large glass of cool water. Your body has just lost a lot of fluid through sweating, and you must replace it right away to avoid a headache.
Next, you need to cool your skin down. The Cleveland Clinic suggests taking a cool or warm shower to wash all the salty sweat off your body. Do not jump straight into a cold pool of water unless you are very healthy and very experienced, as a sudden change from extreme heat to extreme cold can easily shock your heart.
After your shower, find a quiet place to sit down and rest for at least 10 to 15 minutes before you get dressed and drive home.
What toxins do saunas remove?
You will often read articles online that claim sitting in a hot room will “detox” your body and sweat out terrible poisons. This is actually a very popular medical myth.
While sweating feels wonderful and leaves your skin feeling clean, sweat is actually made of 99 percent pure water, mixed with a tiny bit of salt. It does not contain large amounts of hidden poisons. According to the National Institutes of Health (NIH), your body already has a perfect, natural system for removing harmful toxins.
Your liver and your kidneys do all the hard work of filtering your blood and cleaning your body 24 hours a day. You pee and poop the toxins out; you do not sweat them out. The true benefit of the heat is that it relaxes your sore muscles and helps you feel calm, not that it magically removes poisons.
What is the negative side effect of a sauna?
“The biggest and most dangerous negative side effect is dehydration, ” reminds Tunde Rasheed, B.Sc. Researcher. “Dehydration happens when your body loses too much water and does not have enough left to work properly. When you sweat heavily for 20 minutes, you can lose up to a whole pint of water. If you do not drink water to replace it, your blood pressure will drop very low, making you feel weak and dizzy.”
Another negative side effect is dry skin. The hot, dry air can pull moisture from your skin, leaving it feeling tight and itchy later in the day. Applying a gentle, unscented lotion to your skin after your shower can easily fix this problem. Finally, if you fall asleep inside the room or stay much too long, you can actually suffer from heatstroke, which is a life-threatening emergency where your body temperature gets dangerously high.
“Population-based studies involving thousands of people suggest that those who take saunas regularly have lower rates of heart disease than people who don’t take saunas,” says Dr. Prashant Rao, a sports cardiologist at Harvard-affiliated Beth Israel Deaconess Medical Center.
Bottom line
To stay safe and comfortable, you should stay in a sauna for 15 to 20 minutes at a time, and beginners should start with five to 10 minutes. The extreme heat makes your heart beat faster and causes heavy sweating, which can lead to dangerous dehydration and dizziness if you stay inside for too long. Always remember to drink a large glass of water before and after your visit, and leave the room immediately if you ever feel sick or lightheaded.
Frequently Asked Questions
How do you know your body is detoxing?
Your body naturally detoxes and cleans itself constantly through your healthy liver and kidneys, not primarily through the water you lose when you sweat in a hot room.
Are saunas safe for people with heart conditions?
People with heart conditions or high blood pressure must ask their doctor first, because the extreme heat makes the heart work much harder than normal.
Does the sauna detox your liver?
No, sitting in a hot room does not clean or fix your liver; your liver is an amazing organ that cleans itself naturally every single day.
Citations
Sutton J. How Long Should You Stay in a Sauna? Healthline. Published 2024. https://www.healthline.com/health/how-long-in-a-sauna
Mpemwangi H. Hot weather and blood pressure, heart. Mayo Clinic Health System. Published July 23, 2021. https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/effects-of-high-temperatures-on-blood-pressure-heart
Cleveland Clinic. Are Cold Showers Good for You? Cleveland Clinic. Published April 18, 2025. https://health.clevelandclinic.org/are-cold-showers-good-for-you
Baker LB. Physiology of Sweat Gland function: the Roles of Sweating and Sweat Composition in Human Health. Temperature. 2019;6(3):211-259. doi:https://doi.org/10.1080/23328940.2019.1632145