Can a Hot Tub Make You Dehydrated?

I love getting in my hot tub, but I’ve noticed that sometimes I feel thirsty or even lightheaded when I get out. When that happens I’ve wondered can a hot tub make you dehydrated?

I decided to research it and here’s what I found out:

Yes. A hot tub can lead to excess sweating and dehydration in conjunction with other factors such as not drinking enough water, alcohol consumption, or soaking longer than 20 minutes at 104° F. 

But there’s more to know about how to use hot tubs safely, ensure you’re properly hydrated, and the surprising ways both alcohol consumption and the temperature you have your hot tub set to can impact dehydration.

So let’s take the plunge and keep reading!

Can a hot tub cause dehydration?

No. A hot tub by itself will not cause dehydration. But dehydration can occur when using a hot tub in conjunction with potential issues such as soaking longer than 20 minutes at 104° F, consuming alcohol, and not drinking enough water.

But it’s not like a quick plunge will suddenly rob your body of water. Our bodies are made up of 60% water according to the United States Geological Survey which is a government division of the Department of the Interior.

They go on to state that “the brain and heart are composed of 73% water, and the lungs are about 83% water. The skin contains 64% water, muscles and kidneys are 79%, and even the bones are watery: 31%.”

They go on to say that, on average, an adult male needs 3 liters of water a day and adult females need 2.2 liters per day. That amounts to a little over 3 quarts and 2 quarts respectively.

So it stands to reason that NOT drinking enough water before you get in a hot tub is what really creates the dehydration. The hot water just makes it worse and can accelerate those symptoms of dehydration.

The biggest factors that affect dehydration are:

  • Diarrhea or vomiting
  • Excess urination
  • High fever
  • Excess sweat

So obviously the big takeaway from those are doing things that cause our bodies to lose water.

The good news is that a hot tub really can only lead to one of those; excess sweating due to the high temperatures.

Personally, since I have 3 daughters that like to use the hot tub, and one of them is a toddler, my wife and I keep our tub set to 98°. That way we can all enjoy it without too much risk. It also makes it more enjoyable in the heat of summer when the last thing we really want is to bask in 104° water.

What are the symptoms of dehydration after using a hot tub?

Symptoms of dehydration after using a hot tub include excess thirst, feeling dizzy, lightheaded, or sleepy. When those symptoms set in, exit the hot tub safely, and slowly sip water in a seated position until the symptoms diminish.

If you haven’t had enough water today, or have your hot tub set well above 100°, or if you’re drinking alcohol in your hot tub, you could experience dehydration.

If you aren’t sure what that looks like, look for one or more of the following symptoms:

  • Unquenchable thirst
  • Dizzyness
  • Sleepy
  • Not able to urinate
  • Dark-colored urine
  • Disoriented

For young children, you might also see:

  • Dry mouth
  • Irritability
  • No wet diapers for a few hours
  • Lack of tears when crying

Of course, when in doubt, always consult a doctor if you see persistent or concerning symptoms. Better to be safe than sorry.

But for the best and safest results when using your hot tub, make sure and drink plenty of water before getting in. Also, try and avoid heating your hot tub above 100°.

Lastly, take breaks where you get out after 15-20 minutes max to allow your body to not get overheated.

Used safely, your hot tub can provide significant benefit and pleasure to your whole family. We just have to use some common sense.

Is drinking alcohol in a hot tub dangerous?

Alcohol and hot tubs are often used in conjunction. However, excess alcohol combined with low water consumption and soaking beyond recommended limits can expand blood vessels, increase body temperature, and induce symptoms of dehydration such as dizziness and disorientation.

So, possibly is the short answer.

But I say that having done it many times. What I don’t do, however, is have more than 1 drink when I’m in the hot tub.

Having 1 drink ensures I’m not intoxicated which could lead to passing out and drowning. It also helps ensure I don’t get too dehydrated. But that’s in conjunction with some of what I addressed above; not setting the temp too high and ensuring I drink enough water.

Other dangers of drinking alcohol in your hot tub can include:

  • Heat exhaustion 
  • Broken glass – Beer bottles and drinking glasses get accidentally broken all the time. Unfortunately, when that happens in a hot tub, it can be very hard to see and remove all the pieces of glass safely and without getting cut in the process

If you do have a drink in the hot tub, relax. You’re not alone. Just be smart and stay safe. Some of the following suggestions can help with that:

  • Use plastic cups or metal beer cans
  • Don’t have more than 1 drink per hour when exposing yourself to the high heat of a hot tub on and off for that time
  • Exercise caution getting in and out of the tub since even a small amount of alcohol can affect coordination and balance
  • Keep your tub set to no more than 100° – alcohol can have a deadly impact on heat exhaustion

The Centers for Disease Control and Prevention has noted that alcohol is a risk factor for up to 50% of teen and adult deaths connected with water sports and recreation. While most of those are likely related to swimming or boating, it still pays to play it safe when drinking and hot tubbing mix.

Does the temperature of a hot tub affect dehydration?

Yes. The higher the temperature of the water, and the longer you soak, the greater the likelihood of dehydration. Never exceed 20 minutes of soak time when the temperature is set to 104° F.

The biggest way that a hot tub impacts dehydration is by causing excess sweating. So it’s not a shocker that the higher you set your hot tub thermostat to, the more you’ll sweat.

If it’s a hot summer day, that can be magnified.

And, of course, as we’ve already mentioned, other risk factors like not drinking enough water or drinking a lot of alcohol can also impact dehydration and make everything worse.

So what is the ideal temperature for a hot tub?

Lots of people have different opinions here.

Hot tub manufacturer Jacuzzi recommends 104°. Personally, I find that way too hot. It’s also not good for my kids who enjoy getting in the tub with me.

My wife and I keep ours set to 98° although, in the heat of the Texas summer, it’s often a little over that since the sun beats down on the lid all day.

The US Consumer Products Safety Commission has this to say about the proper temperature for a hot tub:

“Hot tub water temperatures should never exceed 104 degrees Fahrenheit. A temperature of 100 degrees is considered safe for a healthy adult.”

They go on to add the following additional precautions:

  • Pregnant women should stick to the 100-degree maximum rule
  • People taking medication which causes drowsiness should not use hot tubs
  • If you have a history of heart disease, diabetes, or blood pressure issues, consult a doctor first

Is it dangerous to stay in a hot tub too long?

Yes. Never exceed 20 minutes of soak time when the temperature is set to 104° F. But lower temperatures also have limits. As a general rule, it’s a good idea to exit the hot tub after about 15 minutes. Always remember to drink plenty of water too.

If you’ve already read the above passages, this should be no surprise. Even a fully hydrated person not drinking alcohol can become dehydrated if they use a hot tub for more than 20 minutes.

That’s even truer if the temperature of the hot tub is above 100°.

Since some of the symptoms of dehydration can include dizziness, being disoriented, and feeling tired, someone could easily injure themselves getting out of the hot tub, or pass out in the hot tub.

For those reasons, it is ALWAYS recommended that you never use a hot tub alone.

So use caution when using your hot tub, ensure you drink plenty of water, and don’t sit submerged in your tub beyond 20 minutes max. If you keep your tub set to 104° you probably want to shorten that to between 10-15 minutes.

But always listen to your body and when in doubt, take a break and get out.

Can you pass out from being in a hot tub?

Yes, although not generally for those drinking plenty of water and following recommended hot tub temperatures and soak times. The higher the temperature of the water, the greater the impact on blood pressure. So never exceed 104° F and soak for a maximum of 20 minutes, with 15 minutes being ideal.

A recent study by the Mayo Clinic looked at excess hot tub exposure where the water was set to 104° for some subjects and 106.7° for others. The test subjects got in the hot tubs for 21 minutes.

The Mayo Clinic determined that, surprisingly, the higher temperature didn’t increase the risk of heart or circulation health. However, the higher the temperature, the bigger the impact on blood pressure.

They noted that the higher temperature caused a 50% increase in blood pressure drop compared to the lower 104° water.

The significant and quick drop in blood pressure can reduce blood flow to the brain and lead to fainting. Passing out, of course, could not only lead to drowning but also head injury if you hit your head when falling.

So again, to use your hot tub safely, never exceed 104°, and even lower is safer.

Did I cover all you wanted to know about whether a hot tub can make you dehydrated?

In this article, we took an in-depth look into the world of hot tubs and how they can affect our bodies.

Everyone knows a hot tub feels great on sore, tired muscles. But depending on how much water we’ve had that day, what temp we have our hot tub set to, and if we have been drinking alcohol, dehydration can set in.

So we looked at the specific question of can a hot tub make you dehydrated?

The answer, perhaps not surprisingly, was yes. Being exposed to high temperatures for an extended period of time could lead to dehydration or other health issues.

For that reason, it’s always recommended you NOT set your hot tub temperature too high.

It’s also recommended to take a break after 10-15 minutes, and of course, use alcohol moderately and safely if you plan to use your hot tub.

What temperature do you like to set your tub to?

Jeff Campbell

Jeff Campbell is a husband, father, martial artist, budget-master, Disney-addict, musician, hot tub lover, and recovering foodie having spent over 2 decades as a leader for Whole Foods Market.

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