Sleeping Bag Breathability Guide: How To Avoid Sweaty Sauna-Bag


Constantly waking up in a sleeping bag filled with sweat? Learn what to do about it here!

Two sleeping bags drying on camping tent

Excessive sweat in a sleeping bag can be addressed by the following:

  • Adjusting ventilation with your tent or your sleeping bag
  • Using lighter sleeping bags and/or clothing
  • Absorption through a traditional sleeping bag liner or with clothing
  • Containment with a vapor barrier liner
  • Alternative outdoor bedding

That said, there’s a lot more to know when it comes to avoiding a sweaty bed while camping. Continue on and you’ll pick up several more tips on avoiding a sweaty sleeping bag, as well as learn about some bedding alternatives that may offer you more comfort while you’re camping.

Why Avoid A Sweaty Sleeping Bag?

A sweaty sleeping bag is a pain in a number of ways. Some of those ways are obvious, like being uncomfortable, while others may not come to mind right away.

Here are a few key reasons it’s a good idea to keep your sleeping bag from becoming a sauna-bag:

  • It’s uncomfortable. No one wants to sleep drenched in their own sweat. It doesn’t feel good. Our sleep is so valuable, especially when we’re in the outdoors and so it’s important to do everything you can to make sleeping comfortable.
  • The sweat gets trapped. If you get sweaty in your bed at home, you can often remove some blankets from on top of you and the air will cool you back down. However, it’s much harder to allow the sweat buildup in a sleeping bag to evaporate so that you can get cool, due to the design. A drenched sleeping bag loses its ability to keep you warm and also gets significantly heavier.
  • You may end up colder. Sweating is our body trying to cool itself down when we’re too hot. Imagine getting cold after a run because the air is hitting the sweat droplets on your body. Likewise, your sleeping bag may end up feeling clammy.
  • It makes sleep more difficult. Not only is the sweat in your bag uncomfortable, but you may feel hot, clammy, or otherwise just unable to sleep. On top of the general discomfort, lack of sleep will just make your trip even more miserable.
  • Your sleeping bag might get funky. Not the disco kind either–Too much sweat buildup can end up being absorbed by the filling inside the bag. If that happens, you’re going to have to do some serious washing in order to get the odor out.

If you’ve ended up with a stinky sleeping bag due to excess sweat (or anything else), it can seem like a hopeless situation. However, we have some great tips for getting the smell out of your sleeping bag so that you can enjoy sleeping in it again. Discover these tips in our article on stinky sleeping bags here.

Tips To Help A Sweaty Sleeping Bag

Before going out to buy a new form of camp bedding, you might want to try out a few ways you can get a sleeping bag to work as you need it to. The good news is that most cases of “sauna-bag” are likely due to a small factor that can be pretty easily fixed once you find out what’s causing the problem.

As you’re trying to resolve your sweaty sleeping bag issues, consider the tips below.

Check The Temperature Rating

If the sleeping bag you are using is rated for 20 degrees, and you’re sleeping in 70-degree weather, chances are you might sleep too warm. The good news is this is an easy problem to solve. You’re likely to find that sleeping bags rated for higher temperatures are less costly.

Before doing anything else, take a look at what temperature your sleeping bag is rated for. If you notice it’s meant for temperatures that are quite low, you may need to get a second, lighter option for fair-weather camping trips.

Alternatively, many sleeping bags unzip to a rectangle. If you use your 0 degree sleeping bag like a comforter you’ll end up being more comfortable.

I know in Texas while summer camping (I know, we’re crazy) that I often find myself sleeping on top of my sleeping bag for padding. There are many ways you can adjust your sleeping situation with what you have.

If you’d like more tips that we’ve had to learn the hard way on how to summer camp in Texas without dying, check out our post here.

Choose Clothing Carefully

The clothing you wear to bed can play a large role in your temperature, and therefore the amount you sweat. However, it is pretty highly debated as to whether you should wear fewer clothes to stay cooler, or more clothing to make it harder for your body heat to spread. Some recommend wearing something light and made of cotton while others claim that cotton is an absolute no-go.

All these methods work, honestly, and it really depends on your body and your situation. We’ll talk about some of these methods in more detail. Just remember that clothing is fantastic because you can take it off or put more on depending on what you need. If it’s cold, it’s always good to be prepared with additional layers that you can take off as necessary.

Clothing Method 1: Wear Clothes To Absorb Sweat

When you’re in cold conditions, it’s tricky to find the exact balance of clothing that will keep you warm enough to sleep comfortably but cool enough to not sweat.

One idea is that your sleeping bag is important to keep dry and therefore it’s worth wearing clothing (or using a liner as we’ll talk about soon) that will absorb the sweat. After the night is through you can let that clothing dry out while your sleeping bag remains relatively drier than before.

In this method: breathable cotton is an excellent choice.

Clothing Method 2: Wear Breathable Clothing That Doesn’t Absorb Moisture

Many swear by breathable clothes for sleeping while camping. The breathability of clothing often has to do with how it’s knit–so just because something is silk or wool doesn’t mean it’s guaranteed to be breathable.

The idea in this method is that try to wear clothing that is as breathable as possible to assist with ventilation. Additionally if your clothes don’t absorb sweat that will prevent your clothes from getting damp which will keep you at a more constant temperature while you sleep.

So in this camp (ba doom psh ?) cotton is not a good material to use even though it’s breathable. Cotton retains moisture really well.

If you want to learn more about whether or not cotton is a good idea for outdoors clothing at all, we have more information in our article on the topic here.

We asked several campers this question and some campers claim that a breathable hat can help your body strike that delicate balance of staying warm enough to stay comfortable but not too warm to start sweating.

Clothing Method 3: Wear As Little Clothes As Possible To Cool Down

As I mentioned, there are a lot of different opinions on how to solve this problem, and one of the ideas is to wear as few clothes as possible if any.

The idea here is that any clothing adds to the insulation of your sleeping system (your sleeping pad, your sleeping bag, etc), and therefore to cool down you need to peel off any layers that you can.

Many people swear by this approach. Your mileage may vary!

Avoid Humid Weather

The more humid the weather is in a particular place, the harder it’s going to be to escape. It’s one thing when you’re creating your own humidity inside of a sleeping bag, but humidity surrounding you from the outside can be oppressive.

When the weather is hot (and humid) enough, you may feel that a sleeping bag isn’t even worth the effort to pack. Before you head out into the wilderness without one, take a look at our article on whether or not you need a sleeping bag for summer camping here.

If you want to avoid sauna-bag, it’s best to avoid camping in highly humid areas altogether. Otherwise, you may just want to bring a few blankets or other lighter sleeping materials that can allow you to ventilate easily. You may still end up sweaty, but at least you won’t be adding to the problem by being trapped in a sleeping bag.

Layer Your Bedding

If sleeping all zipped up in your sleeping bag leaves you sweaty, then you may just need to change up the way you’re using the bag. Try packing some blankets and try using the unzipped sleeping bag as a comforter. You’ll get a bit more space and probably feel more comfortable.

Should you still feel like you’re getting hot and sweaty, you can always peel back layers as needed to allow for hot air to escape. It’s also just as easy to add layers if you’re starting to feel cold. All in all, it’s a method worth trying out that won’t require you to make any big, extra purchases.

An example of a top layer you might try is to bring a simple breathable bedsheet as your top layer. I know for me that my body is used to having some sort of bedding on top of me and so something as light as possible can work well.

If you’re backpacking, you don’t have this luxury. You will have to adjust ventilation and your clothing to achieve any kind of layering.

Ventilate Your Tent

Getting some air flowing through your tent is a great way to help you stay cool. If the air remains trapped too long, it can make your whole tent feel warm and muggy.

Additionally, if you open up a window (while leaving the bug screen zipped up), you can unzip your sleeping bag and give yourself a chance to cool off. Once the sweat has evaporated and you’re feeling more comfortable, you can head back to dreamland.

Often your tent comes with a rainfly. You can adjust the temperature significantly if you sleep without the rain cover. Obviously this is only possible if it’s not raining. ⛈

Our tent without a rainfly while camping during the summer

Use A Liner

Liners can be used for your sleeping bag, or as a part of your clothing in some cases. While most liners won’t stop you from sweating, they can keep it from soaking your sleeping bag or at least make it easier to handle.

This is the sweat absorption technique.

Use a VBL (Vapor Barrier Liner)

One type of liner some campers like to use is known as a Vapor Barrier Liner or VBL. This is a liner that does not breathe. Although that might sound like the opposite of what you want to avoid sweating, there are ways in which these liners can be useful.

One huge advantage to a VBL is that they can be extremely lightweight. VBLs can be as simple as a plastic trash bag. This is ideal for backpacking situations.

For example, you can use VBLs that are made for a specific area, such as your feet. If your feet tend to get sweaty at night, the VBL will keep the sweat trapped and away from your bedding. Additionally, VBLs can be used to track your body temperature, allowing you to make needed changes before you’re sweating all over the place.

So, for example, if your feet tend to get sweaty when it’s too hot, if you put your feet in a plastic bag while you sleep, your feet will start sweating the moment it’s too warm and you will know it instead of your sweat sneakily escaping into the sleeping bag where it can never be detected.

Watch Your Breath

While it may only play a small part in the buildup of condensation, breathing into your sleeping bag can definitely add to the problem. When we breathe out, the breath is warm and it adds to both the heat and humidity inside the sleeping bag.

Depending on your situation, you may need to be fully bundled up with just your nose and mouth exposed, or you may be able to sleep normally with your head outside the sleeping bag. Just be careful to make sure your breath can escape rather than becoming trapped in your bag.

I’ve totally been there. In fact we just went camping recently when it was 30 degrees (see my article about how to stay warm while camping in 30 degree weather if you’re interested). It was so cold (for me) that I had to keep my nose out so I could breathe but my mouth was breathing into the sleeping bag.

In these situations you might try sleeping with a warm jacket with a hood so the sleeping bag doesn’t have to absorb all of that moisture.

Consider Medical Issues

If you’ve tried several different methods for relieving your nighttime sweats and can’t seem to find an answer, there could be some other issue at play. It’s possible some kind of health condition could be contributing to the problem.

This isn’t an attempt to alarm anyone, just a note that if you’re having a tough time with sweat at night, a doctor might be able to help you find a solution.

Try Other Bedding Types

Sometimes a sleeping bag just isn’t the right kind of bedding. Maybe it works for you in some temperature ranges but not in others, or perhaps you just need something different for a good night’s rest. In either case, there are a number of options you can try out to avoid night sweats.

We’ll go over these bedding types in more detail later in this article, but a few such options include camping quilts, regular bedding, or even switching to a Bivy bag or hammock. If you’re willing to explore, you’re sure to find an option that will allow you a more comfortable sleep.

Is There Such Thing As A Non-Sweaty Sleeping Bag?

The answer to this question is based strongly on the cause of sweating. If you’re getting sweaty at night because your sleeping bag is too warm, then yes. There are many sleeping bags out there designed for warmer temperatures that offer a lighter, more breathable design.

On top of that, the materials that are used in making a sleeping bag can play a role in how breathable they are. For example, many consider down sleeping bags to be more breathable than synthetic varieties. As a result, it may be a good idea to experiment with different bag materials to find what works best for you.

Alternatives To Sleeping Bags That Are Less Sweaty

Maybe a sleeping bag just isn’t the right choice for you. Aside from creating a space that is more prone to sweat, they can also feel quite confining and lack the comfort of actual bedding.

Luckily, the following options make for great alternatives when you’re just not feeling the sleeping bag setup anymore.

Quilts

Camping quilts are often considered to be excellent alternatives to sleeping bags, even when you’re camping in extremely cold weather. They are capable of measuring up to even the warmest sleeping bags, so you’ll know you won’t end up freezing if the weather drops.

Caveat: Camping quilts will only keep you as warm as a sleeping bag if you have an appropriate sleeping pad. Camping quilts depend on a sleeping pad that provides some insulation to work properly. In fact, so do sleeping bags.

However, that feature might make you somewhat concerned if you’re trying to avoid a sweaty bed. The good news is that there are types of camping quilts that are designed to help you avoid a sweaty bed and offer more breathability. Such quilts include options like the Ramble (Amazon), which has a hydrophobic design.

Regular Blankets Or Comforters

Just like in your bed at home, standard blankets and comforters are easy to use, more comfortable than a sleeping bag, and tend to breathe a little better. It’s also very easy to add or subtract layers so that you can control your temperature, and therefore the amount you sweat.

However easy this option could be when it comes to sleeping, it’s not really going to be the ideal choice for hikers or backpackers. That said, if you’re car camping and you drive right up to your campsite then this might be the perfect choice for you.

awesome tent sleeping solution
Using comforters and blankets in our tent

Bivy Bags

Bivy bags can be a great replacement for both your sleeping bag and tent combined. As such, they are an ideal choice for hikers and backpackers as well as car campers. Basically, a bivy bag is like an outer shell for your sleeping bag. You get inside, zip yourself up and you’ll be safe from bugs or other critters entering your sleeping area.

In terms of heat, these bags can be used with a variety of different sleeping materials. If you would rather avoid a sweaty sleeping bag, you can tuck some blankets into your bivy bag, or just sleep with some warm clothes on.

Additionally, options like the Bug Bivy (REI) made by Outdoor Research are extremely breathable. This bag allows you to get more airflow and enjoy a night under the stars while remaining safe from bugs.

Hammocks With Insulation

Hammocks can be a fantastic option for anyone looking for a cooler setup to sleep in. Because they are up in the air, you can get a lot more airflow in a hammock than you would with other kinds of camping beds. As a result, there’s less concern about sweat.

Because of this enhanced airflow, hammocks can get really cold. As in… even sleeping below 50 degrees (even with a sleeping bag) might be totally miserable.

Fortunately, there are ways to insulate a hammock. You can use a sleeping pad designed for hammock shapes like this one on Amazon (these are effective but tricky to get positioned just right). The sleeping pad is inserted into the hammock and you sleep on top of it, similar to how you would sleep on a sleeping pad in a tent.

Or, you can use an underquilt like this one on Amazon. An underquilt is basically an insulated blanket that is designed to hang directly under your hammock leaving an air gap between you and the underquilt. The underquilt is very effective to keeping you warm.

If you’re not sure which is better, a sleeping pad or an underquilt, check out our article here.

Down Blankets

Down blankets are ideal when you don’t want to carry a lot of blankets, but need something pretty lightweight and warm. You don’t have to worry about zipping up a down blanket, and it feels a lot more like your bed at home.

Additionally, it’s a lot easier to pull the blanket away from yourself if you’re getting a bit too hot. Rather than having to struggle out of a sleeping bag, you can just flip back a down blanket and you’re free to cool down. It’s a simple, easy way to maintain your comfort without adding too much to your pack.

Warm Clothing

If you’re truly willing to rough it, you can go without blankets entirely. Just lay out your chosen camping bed, grab a pillow, and snooze away. This isn’t the ideal choice for everyone, but for some, it might be just the way to go.

Before you opt for this method, make sure that you’ve checked the weather and know how cold it may get at night. The last thing anyone wants is to head out onto their camping trip only to find that it’s just too cold for them to get a good night’s sleep.

A good way to test your theory out is to try and sleep in your backyard.

Backcountry Beds

If you’re interested in options that are close to sleeping bags, but not quite the same, then a backcountry bed could be a solution. These camping beds are quite similar to sleeping bags. They often use the same kinds of materials and basic design. However, backcountry beds like the Frontcountry Bed (Amazon) made by Sierra Designs offer a bit more freedom.

Depending on the temperature around you, you can either bundle up tightly in the bed, or you can use it to just cover the lower half of you if you want more air and space to move around. All you have to do is adjust the bed setup to fit your desired temperature, and you’ll be good to go.

Peter

Peter is a software developer who loves to take every opportunity to go outside that he can get. Peter grew up going on long backpacking excursions with his family every Summer and now enjoys staying at the beautiful Texas State Parks and swimming in the amazing Texas Rivers.

Recent Posts