I came across a TikTok video of a guy trekking across Scandinavia. In the video, he gets into his sleeping bag wearing only boxers. The comments were divided between people claiming that sleeping naked is warmer because a sleeping bag traps heat from your body more effectively without cold clothes, and those saying wearing clothes provides additional insulation and therefore more warmth. Which is true?
Wearing clothes inside a sleeping bag is definitely warmer. The myth that sleeping naked keeps you warmer isn’t based in fact. However, wet or overly tight clothing can indeed make you colder by either drawing heat away from your body or restricting blood flow. Clothes help keep body warmth close to you, and additional layers like a puffy jacket or fleece pants will increase warmth within the bag.
@Quincy
What exactly do you mean by tight? Like uncomfortably tight, or skin-tight that doesn’t hinder movement but fits closely?
Briley said:
@Quincy
What exactly do you mean by tight? Like uncomfortably tight, or skin-tight that doesn’t hinder movement but fits closely?
Generally, anything that leaves an imprint on your skin, like socks that leave rings around your ankles when removed, or pants that are tight around the waist could be problematic for warmth. A snug pair of leggings might be okay as long as they don’t impede circulation. When unsure, it’s safer to choose looser clothing.
You’ll generally be warmer with layers as long as they are dry. Similar to how you would layer under a down jacket while hiking. I’ve backpacked in very cold temperatures and using a sleeping bag liner has also significantly added warmth.
While it’s true that wearing clothes is warmer, there are more efficient ways to manage the weight/bulk of clothing or sleepwear. For instance, carrying a down jacket and pants could be substituted by a warmer sleeping bag or quilt due to the ‘mitten effect’—sharing a warm microclimate is more efficient than the ‘glove effect’ of isolated sections created by individual clothing pieces.
Wearing clothes is warmer than not wearing them in a sleeping bag. Clothes also help protect the sleeping bag from body oils and wear.
The idea that it’s warmer to sleep naked is nonsense. More layers mean more trapped air, which is how insulation works to keep you warm.
Sleeping without clothes can feel sticky and uncomfortable, and isn’t very hygienic after a long day outdoors. I find wearing clean, dry clothes like merino wool, which regulates temperature well and prevents odor, much more comfortable and efficient for maintaining warmth, especially with additional layers like a down hoodie in colder conditions.
Experiment with this at home. Try sleeping in warm clothes like sweatpants and a fleece under the covers and note if you overheat. Then try sleeping without any clothes and compare the warmth.
Layering generally means more insulation. However, too many layers or very thick layers can slow down the heating process inside the bag and can be uncomfortable or restrict circulation if not properly fitted.
From my experience in the army, sleeping with minimal clothing, often just underwear, felt warmer and more comfortable than wearing several layers. I would keep my day clothes at the bottom of the sleeping bag to keep them warm for the morning.
In my opinion, it’s not necessarily warmer, so it’s more about personal comfort. I use my clothes as a pillow since I sleep with a cotton liner.
The idea of removing clothes to get warmer in a sleeping bag doesn’t really hold up in practice.
The warmth might depend on who else is in the sleeping bag…
I usually sleep without clothes because I find it too warm otherwise.
The person in the video might have avoided bringing separate sleeping clothes, perhaps because his hiking clothes were damp. In that scenario, less clothing might feel warmer.
Consider the practicality of getting up in the middle of the night without clothes on, especially in cold conditions.