20 Ways to Increase Sleeping Bag Warmth

It must be getting colder outside because I’m on the hunt for ways to keep warm lately … either that or the YouTube algorithm sent me down a rabbit hole because every other video they recommend has something to do with cold weather survival, lol. (Or maybe they know something I don’t and are trying to warn me?) I’ll summarize the video as I go through it below. And if you want links to the gear he discusses, see the video description on YouTube. Enjoy!

1. Adjust your feathers and down. If your sleeping bag has continuous baffles, you can unzip it, shake the down, and shuffle it into the chest area to warm the bag up.
2. Add a liner. A thermal reactor liner (like those from sea2summit) can increase the warmth by maybe five to maybe seven degrees.
3. Add a vapor barrier liner. Make sure to put the vapor barrier liner inside your bag, as putting it over your bag will cause perspiration and respiration to fill the down and make things colder.
4. Get some booties. Down booties, which are only a couple of ounces, make a huge difference.
5. Increase and improve your ground insulation. Upgrade from a basic, light-duty, thin pad to an insulated pad (like the Thermo Rest Extreme).
6. Use double pads. Add a Z rest on top of an extreme thermal or a down light pad in extreme locations like Denali, Antarctica, and Greenland.
7. Wear some clean wool long underwear. Adding wool long underwear on a shirt and on your legs can make a difference, as wool will keep you warm even if you are sweaty and grimy.
8. (I think he missed this one. What could it be!?)
9. Air out your sleeping bag every morning. Unzip your bag, open it up, and flip it completely inside out, even if it is super cold or if you have some sun, to allow perspiration and respiration to evaporate out.
10. Eat some high-energy food right before you go to bed. Eating some high sugars right before bed will get your metabolism cranked and help warm you up.
11. Do some jumping jacks or push-ups before you get into bed. Flapping your arms and jumping up and down builds up heat by using your muscles.
12. Pre-wrap your bag on you as you’re sitting in the tent. Lay on the bag to warm it up several degrees so it is not minus 30 or minus 40 when you get in.
13. Add some hot water bottles to your sleeping bag. Get some boiling water, put it in your Nalgene, screw the lid tight, turn the bottle sideways, ensure it does not leak, and put the water bottle in a waterproof bag.
14. Go relieve yourself of bodily fluid prior to going to sleep as in go pee. Doing this gets rid of the cold “I need to go” reaction where your feet get cold and miserable, and you will feel warmer and sleep longer.
15. Wear a hat. Wearing a hat can warm yourself up a lot, based on the theory that you lose at least 20 percent of the heat out of your head, though I believe this is a myth.
16. Wear fresh wool socks. Do not wear the socks you have worn all day that are sweaty, and always have a clean pair dedicated just to sleeping. For hardcore cold, get the Mountaineer or Expedition smart wool socks.
17. Wear a neck buff. Use the Pollard style neck buff that has a much thicker fleece lining around your neck to increase the warmth of your sleeping bag.
18. Use the fleece pillow jacket. Bring a fleece jacket to wear as a layer above your inner shirt, and use it as a pillow.
19. Wear less clothes. If you end up compressing the down from the inside by wearing too many clothes, you will actually make yourself colder; the general saying is “sleep near naked,” meaning wear basic boxer underwear, long underwear, and some sort of shirt (a fresh, thin, or long sleeve shirt).
20. Open your bag early. As soon as you get into your tent, pull your sleeping bag out of the stuff sack and jam it up against the wall of the tent so it can expand (real oft), otherwise you will freeze for a long time.
21. (Bonus) Layer a down jacket over your feet or chest for added warmth; do not use anything heavy.

Two Things Not to Do:

1. Do not add a blanket to your sleeping bag. Adding a blanket or regular fleece clothing on top of the sleeping bag compresses the down, which will actually make you colder.
2. Do not wear cotton t-shirts, cotton pants, cotton socks. Cotton will make you colder when it is super cold because it picks up oil and does not retain heat; use wool or synthetics instead.