There's always this myth that sleeping naked in a sleeping bag is warmer than wearing clothes in a sleeping bag.
I believe this myth probably originated from the advice that you shouldn't get into a backpacking sleeping bag in cold, wet clothes.
Maybe you've even been told by both military and civilians that sleeping naked in a sleeping bag is warmer than wearing clothes inside the bag.
You might even hear this advice from a surplus store employee to a customer.
However, many experienced campers choose to strip down to their underwear or even nude in their sleeping bags.
So should you wear clothes in a sleeping bag?
The answer is Yes, wearing clothes in a sleeping bag will help make you warmer, protect your bag from dirt, sweat, and body oils, and makes you ready to get out of the bag at any moment instantly.
While sleeping naked or stripping down to your underwear might work in the summer, it's always better, warmer, and more comfortable to wear your long johns, pajamas, or sweat pants.
Sleeping naked in a sleeping bag will prematurely wear your sleeping bag, expose the bag to dirt, sweat, body oils, make you colder, and put you in a compromised situation where there's only a thin fabric wall between you and the surrounding.
Now that you have an idea of whether or not to wear clothes in a sleeping bag, let's look at how sleeping bags work to understand sleeping bag insulation better.
After that, I'll also share with you some essential tips to staying warmer in a sleeping bag and answer some frequently asked questions about wearing clothes in a sleeping bag.
Let's dive in.
How Sleeping Bags Work
Sleeping bags are essential for camping, backpacking, and other outdoor adventures. They are designed to keep you warm by trapping the heat produced by your body and preventing it from escaping so that it's sufficient to keep the inside of the bag warmer.
It works just like a room, with insulation that prevents heat from escaping to the outside environment.
Wearing clothes in your bag adds a base layer/creates a barrier between you and the ground or outside air. So more clothing equals more layers of air created around your body, and the more layers of warm air you create around your body, the warmer you'll be.
By striping down, you remove the base layer, and your body heat will warm up the bag directly, resulting in more warmth over a short period but will not last long. This is because R values are cumulative, and sleeping naked in a sleeping bag warms the bag up faster, but overall, it is colder as it provides less insulation.
By adding a base layer, your body heat will have to heat that too, so it will take longer to warm up the entire bag. More layers equal more warmth!
However, if you choose to strip down or sleep naked, we highly recommend packing a sleeping bag liner to make you warmer at night and keep your sleeping bag clean.
What Should You Wear in a Sleeping Bag?
The best practice is to wear snug-fitting, wicking long base layers (top, bottom, socks, and hat) in your bag to keep you warmer in cold weather and keep the bag clean.
Wearing loose-fitting clothes will help trap warm air near your skin's surface and prevent your feet or hand from getting cold due to loss of circulation.
While you can increase your sleeping bag's insulation by wearing an insulated coat or pants, you will want to make sure that the bag's shell is not pushing hot air out of its baffles.
If your clothes are wet or damp, it is better to dry them out before getting into your sleeping bag.
It's not a good idea to wear your clothes if they are wet or damp, but assuming they are dry, you should choose a light layer from neck to ankle and wear warm socks.
Below is a breakdown of what each piece of clothing does for warmth:
- Hat: Provides warmth by blocking wind
- Coat: Provides insulation from cold ground or air
- Pants: Provides insulation from cold air
- Socks: Provide insulation from cold ground or air
When it comes to choosing the clothes to wear in a sleeping bag, it's good to choose something in which you won't sweat, and even if you do, the material should be able to pull that moisture away from your skin and out of the sleeping bag (hopefully) where it will evaporate.
It is important to note that the amount of heat produced by your body during the night can change largely based on how recently you ate food. So if you start to sweat at night, you can unzip your sleeping bag to allow cool air to get inside and then re-zip it when you start feeling cold.
It would help if you kept in mind that sleeping warm in a sleeping bag does not happen, and your experience will vary depending on the steps you take to sleep comfortably.
These can include but are not limited to revving up your metabolism by eating something when you get chilled, wearing loose dry clothes, and venting your sleeping bag when you're too warm.
Should You Wear Socks in a Sleeping Bag?
Wearing socks can help keep your feet warm. But if you have worn your socks for hiking during the day, you should clean and hang or spin them in a net bag to dry before wearing them. Sweaty socks will rub sweat into the lining of your sleeping bag, thereby reducing cleanliness and inviting bad odor fungi, and reducing loft efficiency.
Here are some things to keep in mind when wearing socks in a sleeping bag:
Ensure the socks are clean and not sweaty
The socks are not used for anything but sleeping in
Socks are a snug fit, not a tight fit
Why Should You Not Sleep Naked in a Sleeping Bag?
Let's go over the disadvantages of sleeping naked in your sleeping bag.
Makes You Cold: It's always warmer to wear clothes to bed, though there are some exceptions to this. Every layer of clothing you wear when sleeping adds insulation between your body and the outside. While this is not a big deal in the summer, it can increase your bag's temperature rating on cold nights.
Makes Your Sleeping Bag Dirty: Dirt, body oils, and sweat from your body will make your bag dirty when you sleep naked, and you don't want to get that grime on your sleeping bag. Wearing clothes to bed is a sure way to protect your sleeping bag from dirt so that you don't have to wash it after every camping trip. You can even use a sleeping bag liner to further protect your bag from dirt.
Frequent Washing: You'll have to wash your bag every time it gets dirty (as a result of sleeping naked inside), which you need to avoid. Frequently washing your sleeping bag can affect the insulation compacts by making it less effective and running the risk of tearing the bag. Wearing clothes reduces the amount of dirt, especially when you pair them with a sleeping bag liner, so you may not have to wash your bag more than once in a season.
You'll Not Be For Action: Wearing clothes to sleep makes you ready to get out at a moment's notice instantly. You will never know when you'll get up in the middle of the night, and maybe you have to pee, do something, or are even chased by wild animals (yes, it does happen). So needing to wear your clothes will slow you down and prevent you from Instantly taking action (you might even end up running out naked in case of wild animals).
How Can I Increase the Warmth of My Sleeping Bag?
Here are a few tips on how to increase the warmth of your sleeping bag:
Wash the Sleeping Bag
If your bag is old and doesn't seem to be as warm as it used to be, you may need to give it a good wash. This is because as you use the bag over time, dirt, sweat, and oils from your skin, together with moisture caught in the filling, will end up causing the stuffing to clump together, preventing the bag from fluffing up to keep you insulated and warm.
The bag's filling will need to puff up and expand with air to trap the heat produced by your body. So washing your bag will help clean the filling and enable it to flop up more effectively. This will allow the bag to trap more warm air and increase the insulation between you and outside cold air.
Wear a Beanie and Socks
About 30% of the heat lost by humans is through their heads. Wearing a beanie to sleep or tightening the hood of your sleeping bag can help trap more warmth.
Additionally, wearing socks and gloves to bed can keep your hands and feet warm for a better night's sleep.
Add a Thermal Liner
If you're camping in an area that's cooler below the temperature your sleeping bag is rated for, you can consider adding silk, cotton, or fleece liner to increase the warmth of your sleeping bag.
A thermal liner is made from the same material as thermal underwear and is mainly designed and rated to boost the warmth of a sleeping bag.
Adding a liner to your sleeping bag will not only be an excellent combination for the winter, but you can also use it on its own in average weather conditions.
You can choose to get a removable sleeping bag liner as it helps keep your bag cleaner, thereby leaving your filling in a better condition.
Add a Hot Water Bottle
Adding a hot water bottle to your sleeping bag can also help increase your bag's warmth, especially if you're camping in a colder environment.
You heat the billy before bed and pour the hot water (not boiling) into the hot water bottle and then tuck the bottle into your bag for some snug comfort. You can even prepare it ahead of time so that you preheat the bag before hopping in. A regular water bottle will also do, but you need to ensure that the bottle won't leak and don't make the water too hot.
Known as a "base layer," thermal underwear is the warmest set of pajamas you'll need when camping in cold weather conditions. They work by trapping warmth directly against your skin to keep you warm.
It'll be a good idea to add your layers and warm them up by the campfire before getting to sleep so that the heat will build up and become easier to maintain once you hop into the bag.
Eat a Decent Sized Dinner
Eating a decent-sized dinner that is full of low GI carbohydrates will make your body use a lot of energy to digest it.
This will make your body keep burning fuel throughout the night, and the energy produced will produce heat to keep you warm at night.
However, you shouldn't overeat and go easy on the garlic, or else you'll wake up with indigestion.
Proper Tent Ventilation
While this isn't directly related to increasing the warmth of a sleeping bag, having a bit of airflow in the tent will help ensure condensation from your breath, and damp clothing does not cause your sleeping bag to get damp.
You should also not pull your sleeping bag over your face. Your breath's condensation will get into the bag and make it wet.
Exceptions to the Rule
With everything in life, there'll always be an exception. While it's rare, there are times when wearing clothes in a sleeping bag will not keep you warmer.
Below are some of the exceptions for completeness:
Wearing Too Much Extra Clothing: sleeping bags use their fluffy insulation to trap the heat from your body. Wearing so much extra clothing or filling your sleeping bag with so much extra stuff will compress the insulation in the baffles of the sleeping bag, thereby reducing the amount of air it can trap. However, wearing a light base won't affect the bag's insulation, but stuffing the bag with too much extra stuff can impact the temperature rating.
Excess Sweating: If you sweat like crazy at night, it will degrade the insulation of your sleeping bag just as it dries up, just like wet clothing; however you'd have to sweat a lot for this to happen. So you can unzip your sleeping bag if you feel the sweat coming, or sleep without a shirt or clothes and use a sleeping bag liner to protect the bag while increasing warmth.
Less Blood Circulation: Wearing tight-fitting socks and long underwear might reduce the blood circulation in your body. So less blood circulation to your extremities will make you feel colder.
Wearing Wet Clothing: It's never a good idea to hop into your bag with wet clothing or fresh out of the shower. Moisture from your clothes or wet body will end up soaking into the bag and reducing insulation.
Best Way to Sleep
Below are some ways to better sleep in a sleeping bag while maintaining warmth:
- Wear dry clothes/base layer to keep your sleeping bag warm and clean. Choosing loose-fitting clothes will keep you warm without cutting off blood circulation.
- Use your sleeping bag's zipper to regulate the temperature in the bag. Unzip it when you start feeling sweaty and zip back up when it gets colder. Your body heat will keep changing throughout the night, so you might need to unzip it after a few hours.
- Buy a sleeping bag that will give you enough space to move around. Small bags are not comfortable to sleep in, especially with bigger guys, and that extra space can help increase warmth in the bag.
- Use a sleeping bag liner to add an extra layer of insulation and protect the bag from dirt, sweat, and body oils. Sleeping bag liners are easy to wash and can significantly increase the temperature of your bag. You can even ditch your sleeping bags completely when the weather becomes warmer and instead use your bag liner.
- Never sleep in your bag with your clothes wet, and if you don't have access to dry clothes, you'll be better off stripping them off.
Ways of Heat Loss from Your Sleeping Bag
Below are some of the significant ways of heat loss from a sleeping bag:
Radiation - your sleeping bag cannot contain the heat emitted from your body. A liner can be used as an added perk to prevent this.
Conduction - when your body comes in contact with the ground, it sucks up your body heat, making you feel colder. An excellent way to combat this is by using an efficiently insulated sleeping pad between you and the ground.
Convection - the cold air around you also whisks away heat from your bag. Sleeping in an enclosed air tent will help protect against rapid heat loss by blocking breezes to prevent windchill.
Wearing clothes in a sleeping bag adds a layer between you and your surroundings which helps keep your sleeping bag warmer. Stripping down or sleeping naked will remove this base layer, which will make the bag colder and affect the bag's insulation.