One thing many people don’t imagine is that when you sleep at altitude, your sleeping bag is not just for sleeping. It becomes almost like your little home for the night.
Between 3,500 and 5,700 meters, I always keep several things inside my sleeping bag with me. Not because I want comfort like in a hotel, but because up there, anything you leave outside can get very cold, freeze, or simply make your morning harder.
The first thing I always keep inside is a bottle with hot water. I drink water during the night, and if I leave it outside, it can become icy cold. But that same bottle has also helped me more than once with something else: opening the tent zipper.
Sometimes, during the night, the tent zipper freezes. And when you need to open it, it is not as simple as just pulling it. I quickly pour a little bit of hot water on it and then you have to pull the zipper straight away, because in just a few seconds it can freeze again. These are the small mountain details that nobody tells you before, but up there they become very real.
Inside my sleeping bag, I also keep a small bag especially for electronics. I keep my phone, power bank, watch and the most important things inside: spare batteries, chargers, the mini pump for inflating the sleeping mat, headlamps and small accessories that I don’t want to leave out in the cold. At altitude, batteries drain much faster, so I prefer to keep everything protected and close to my body during the night.
Another thing I always keep with me is the clothing I’m going to wear in the morning: my thermal top and trousers. Putting on cold clothes when you wake up inside a tent or a freezing room is not a very pleasant feeling. This way, at least the clothes keep a little bit of warmth and the morning feels a bit more human.
Sometimes I also put the inner boot from my double boots inside the sleeping bag, so it doesn’t freeze during the night. Not always, but when it is very cold, I prefer to keep it inside with me or between my things, because putting on a frozen boot in the morning is one of the worst feelings at altitude.
I’m speaking only from my own experience. At these altitudes, I personally sleep best with good leggings, warm socks and a good thermal top. I don’t like sleeping with too many layers, but what I wear has to be good quality, dry and warm.
And of course, a headlamp always needs to be close. If you wake up during the night, you don’t want to start searching for things in the dark. The headlamp has to be somewhere you can find it quickly.
In the end, sleeping at altitude is not just about getting inside a sleeping bag and closing your eyes. It is about organizing your little world so you can get through the night better.
Your water, your clothes, your batteries, your light, your basic things.
Everything close.
Everything protected.
Because up there, a better night often depends on these small details.
And this is only one part of what happens inside a sleeping bag at altitude. Later, I will also share how I protect my head and face while sleeping, because up there the cold doesn’t only come through your feet. The wind, the dry air and the loss of heat during the night can make a big difference, and small details can completely change how well you rest.