Can Using a Sauna Dehydrate You? Important Things to Know!

Medically reviewed by Dr. Justin Ternes
As an Amazon Associate we earn from qualifying purchases made on our website.

The sauna is an integral part of some people’s daily regimen. Many people use it directly after an intense workout, some use it first thing in the morning, and others use it to wind down before going to bed. However, no matter what time of day you use the sauna, your body will get hot, and you will always break out in a sweat. Sweating is your body’s temperature regulation response to the high heat of the sauna.  

Saunas use will make you sweat and they can dehydrate you. If you’re not sweating in a sauna, then you are likely already dehydrated. To prevent dehydration, drink plenty of water before, during, and after your sauna visit.

With the amount of sweat that saunas cause, you’ll have to drink lots of fluids to stay hydrated. If you’re visiting a sauna after an intense workout or plan to remain in one for a long time, then you need to be extra cautious of dehydration. If you want to learn more about how saunas dehydrate you, the symptoms of dehydration, and how to prevent it, keep reading!

How Saunas Can Dehydrate You

Man relaxing in a sauna

The way saunas dehydrate you is simple. Your body sweats, reducing the overall amount of water in it. Since the saunas are so dry, your sweat evaporates then you sweat even more. It’s a continuous loop; you will keep sweating as your body attempts to cool itself and regulate its temperature – this is also called homeostasis.

While sweating is good for your skin, pores, and overall health like we talked more about in our guide, it carries the risk of dehydrating you if you do not drink enough water. So be sure to have a bottle of water or two on standby, moreover, paying close attention to how long you sit in a sauna is a great way to ensure your health.

How to Tell if You’re Dehydrated

Your body becomes dehydrated by losing more fluid than it consumes. The sauna is the perfect environment for you to lose too much water without replenishing it fast enough. If you don’t have enough fluids in your system, your body’s normal, vital functions can become compromised. 

Dehydration can lead to serious medical events and could be fatal. While you are in the sauna (and after you leave), you should be aware of signs of dehydration so you can combat it by drinking more water and electrolytes.

Dehydration Symptoms 

You might be surprised to learn that your level of thirst isn’t always the best indicator of your body’s need for water. Some adults, particularly older ones, have no thirst until they are past the point of dehydration. The systems of dehydration for adults include: 

  • Dark urine
  • Infrequent urination
  • Lack of sweat in the heat
  • Headaches or migraines 
  • Fatigue and dizziness 
  • Confusion 
  • Irritability 
  • Thirst  

In other words, dehydration can sneak up on you. You want to avoid dehydration altogether, so ideally, you should be making sure you drink enough fluids to prevent these systems. If you go too far, you’ll suffer from one or more of these symptoms. Experiencing symptoms doesn’t mean you’re “tough;” all you are doing is just unnecessarily harming your body and reducing your overall well-being and immune function. 

If You Got Dehydrated by a Sauna Should You See the Doctor? 

Usually, saunas only cause mild dehydration, which can be remedied by chugging some good old water (or a sports drink if you prefer). If you overdid a sauna visit and you think you are suffering from a more extreme case of dehydration, you should go to the doctor if you have: 

  • Persistent abdominal or back pain
  • Dark urine lasting for an extended period
  • Bloody or black stool
  • Loss of sleep
  • Inability to keep fluids down

Dehydration Risk Factors and Complications 

Infants, children, and the elderly are more at risk of complications from dehydration. It is not recommended for children to use the sauna at all. If you are an older adult, be especially cautious about your level of hydration. When you get older, your fluid levels and your thirst sense both lessen. 

Suppose you suffer from chronic illnesses such as heart disease, diabetes, and kidney disease. In that case, you are at a much higher risk of dehydration, and you should consider avoiding the sauna entirely. Talk with your doctor if you are unsure if using a sauna is healthy for you. 

Some complications that can occur from severe cases of dehydration are death, heatstroke, kidney and urinary tract infections, seizures from lack of electrolytes, heart palpitations, and hypovolemic shock (low blood volume). These are just possible more severe complications that are not common occurrences in a sauna unless you are staying for multiple hours at a time and not drinking any fluids. 

How to Prevent Dehydration when Using a Sauna

MIFXIN Wooden Clock Timer Non Ticking Silent Battery Operated Decorative Round Wall Clock for Sauna Room Living Room Home Decor Sauna Room Equipment and Accessories

Dehydration from sauna use can be easily avoided with a straightforward trick- drink lots of water and fluids! As you should know by now, when you are sweating in the sauna, your body is losing fluids. Drinking water replenishes the fluids you lose through sweat. 

Beginner Sauna Users 

If you’re a beginner sauna user, you should limit your sessions to 5 to 10 minutes and drink water before and after the visit (use this clock from Amazon to keep track of the time). Don’t just jump right in for 1 hour for your first foray into a sauna.

You won’t be impressing anyone, well, maybe some doctors if you get too dehydrated. As your body acclimates to the sauna, you can slowly add additional minutes to the length of your stay. However, also do proper hydration. Drink water before the sauna visit.

If you start to get a headache in the sauna or notice that you’ve stopped sweating, get out and drink more water. Additionally, as a beginner, you probably should not visit a sauna multiple times a day. If you want to get to that level, slowly work up your tolerance. 

Experienced Sauna Users

If you’re a pro sauna user with lots of experience, it’s recommended to limit sauna visits to 20 minutes at most. However, you can go longer if you wish. Take breaks every 15 to 20 minutes to replenish your fluids and get back to normal.  

If your body is well adjusted to multiple visits to the sauna in one day, feel free to let loose and do this. Again, as long as you are hydrating and not shocking your body with a sudden increase in length of stay and frequency, you should be able to avoid dehydration. 

Other Sauna Dehydration Avoidance Tips

If you’re doing a post-workout sauna, be sure to drink a lot of fluids because you were exercising and sweating before you went into the sauna. Sweating during your intense workout then later in the sauna has compounding dehydration effects. 

Establish a routine for your sauna sessions. Always plan to drink a bottle of water both before and after the sauna. Then shower, then moisturize when you are done. Drinking water will rehydrate you, showering will lessen post-sauna sweating, and moisturizing will lock moisture (water) into your skin. 

Lastly, the act of sweating carries electrolytes such as potassium, sodium, and magnesium out of your body. These electrolytes can be replenished by eating a well-rounded diet in most cases. However, to ensure you do not lack electrolytes, you can supplement with an electrolyte sports drink. 

The Bottom Line on Saunas and Dehydration 

As we’ve discussed before in our guide on saunas and skincare, saunas are overwhelmingly good for your health and well-being. They improve your immune system, boost your skin health, benefit your cardiovascular system, and help prevent the onset of Alzheimer’s disease and dementia. 

However, if saunas are used for too long, they can cause dehydration. Dehydration can sneak up on you, and you should always be mindful of the signs and symptoms of dehydration. Don’t be foolish and jump into a sauna for a long time on your first go around.

Chances are you’ll suffer from mild dehydration. Preventing injury and harm is why proper hydration is stressed before, during, and after your sauna visits. Even if you do not feel thirsty, drink some water. Your body will thank you later. 

Leave a Comment