How to Make a 40-Degree Sleeping Bag Warmer?
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In this article, I am going to show you how to increase the warmth of a sleeping bag. Let’s go through a scenario. Let’s say that you’re going to go out for a trip where the temperatures may dip down to roughly 30 degrees but your sleeping bag is only good for 40 degrees. What do you do? Well, the best thing to do without a doubt is to get a sleeping bag that is right for your conditions. But if you don’t have the money, there are ways to extend the temperature range of your existing bag.

Add a Bivy

First off, one incredible way to extend the temperature range of your bag is to add a bivy over the top of your sleeping bag. A bivy by itself will block out the wind. It will block out the moisture and will add 5 to 10 degrees of warmth to your entire sleep system. In the coldest months of the year, I always carry a bivy with me. It doesn’t matter if I have a 4-season tent or a 3-season tent, I always have one because it does such a good job of trapping that warm air and that elevates my sleep system.

Now, something to keep in mind is that a bivy can be expensive. But they’re multifunctional. So, if you have one, bring it along with you that will increase the temperature range of your bag.

Use Sleeping Bag Liners

Next up, there are products out there that are known as sleeping bag liners. These can add 5 to 10 degrees to your sleep system and these can be found in all different types of materials. Some are better than others but you can find these in silk, bamboo, fleece, etc.

Think of a sleeping bag liner as a sort of sheet that goes inside of your sleeping bag. It keeps the sleeping bag clean and keeps you warm. You may have a sleeping bag that’s rated for 40 degrees and you may have one that’s rated for 50 degrees. Add them together combined in a sleeping bag. This is an amazing way to extend the range of your sleep system. Yes, it does add some weight to your overall carry but you can stay very warm doing this, which is an excellent example of how layering works.

Add More Clothing

This is another method that involves adding clothing to your sleep system. Many times I’ve taken a 30-degree bag and I’ve taken it all the way down to a low 20. I’m able to do that by adding a nice warm jacket, a good pair of tights, and some nice warm socks, and together I’m able to sleep comfortably. Also, do not forget your beanies which are very important. A nice warm toboggan toque beanie whatever you want to call it that will assist you with keeping you warm. If you have rain gear, you can slip that on over the top of your clothes and that will hold in quite a bit of heat as well.

Use a Warm Sleeping Pad

The next thing that you can do is start thinking about sleeping pads because that is a very important aspect of your overall sleep system. What is the R-value of your sleeping pad and what can you do to add some additional protection between you and the ground? Oftentimes, taking two sleeping pads and putting them together will do the trick. Seriously folks, do not discount the power of the sleeping pad. The right amount of protection from the ground can make all the difference in the world, all the difference between being cold and being warm while you’re sleeping.

Use a Hot Water Bottle

The next tip involves a nice bottle full of warm water. If you’re going to do this make sure that the container is watertight. Boil some water before you go to bed and put it in a container which you can cuddle up with. Oh, man! Nothing is better than that. Hopping inside of a cold sleeping bag with a nice bottle of warm water that you’re cuddling up to, nothing is better. In the winter and in the fall, I do this all the time.

The most important thing to keep in mind with this element is that container should be reliable. You do not want to take any chances on that coming loose and spilling out inside of your sleeping bag. Take those precautions you will stay incredibly warm I promise you.

Eat before you sleep

Eat before you go to sleep because your body will begin to digest that food, break it down and that creates heat. The difference between going to bed full and going to bed hungry is dramatic. When it comes to what you’re going to eat focus on fat because that’s harder for your body to digest. It takes more time and creates more heat. Think of peanuts, nuts, olive oil, and stuff like that. Even cheese is a good food to eat before bed because that is going to keep your furnace going all night long.

As far as extending the temperature range of your sleeping bag, those are some great examples. I do have a pro tip for you and that involves when you’re going to bed, go to bed warm. Do not go to bed cold. Well, you may be asking yourself well how do I go to bed warm. Before you turn in for the night, do whatever you have to do to warm up. Do a little jog, some jumping jacks to heat up your body because that heat that is being released from your body will go right into your sleeping bag and you will be way warmer.

Do not exercise to the point where you’re sweating. That’s not what you want to do but you want to get warm. Once you up inside of your sleeping bag, and then take your clothes off. That way, you don’t lose that precious heat.

Make sure to test out any of your combinations when it comes to extending the warmth range of your sleeping bag before you head out on the trail. You want to ensure that your enhancements to your sleep system will get you to the level that you want to be at. Don’t discover this in the middle of the night in the middle of nowhere that you’re going to be cold all night long. Remember, some people sleep hot some are cold. Your mileage will vary.

The last point deals with something that I touched upon before. The best way to go about staying warm at night is to have a sleeping bag that is right for the environment that you’re going into. You can do combinations, you can do enhancements, and they do work but nothing is going to be more efficient than a good sleeping bag.