Mountaineering and Winter Backpacking Sleep System for Below Zero Temperatures & Manageable Weight
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As I mention in the video, backpackers - and particularly thru-hikers - talk about base weight. Essentially, that is everything accept your consumables. The idea is to keep the base weight low enough to make the long distances pleasant, rather than torturous. Of course, you also need to keep it high enough to make camp comfortable enough, too. And there in lies the balance between hiking first and camping second or the other way around.
When getting into multi-day excursions on snow in the alpine, the situation is a bit different. I simply need more tools to do the job. I will need an axe and crampons. I will need you a stove and fuel to make water, and I’ll need a camp set up that can protect me from fairly extreme temperatures.
When I think of the “big ticket” items in terms of weight (that isn’t fuel or food), I think of tents, sleeping bags, and ropes; these are the items I think you can find the biggest swings in weight across different gear options that supposedly “do the job” in the environment into which I am heading.
Now, that isn’t to say that other items can’t have significant swings in weight. There can be significant differences in boot weights. I can find ice screws that weigh three ounces less than other options; add in a dozen screws and that can be quite a lot of weight, actually.
But as singular items, it’s tents, sleeping bags, and climbing ropes. I see tents in the high peaks that range from 3 to 9.5 pounds. That’s a huge difference. A zero degree sleeping bag can run from almost 4 pounds to 2.75… and that’s before talking about quilts, as I eventually got to in the video. And climbing ropes can run from uppper-40 grams-per-meter to low-60s grams-per-meter. Add that up over 60 meters, and you can see nearly two pounds of difference in rope weight.
That’s why I spent so much time and energy dialing in a sleep system that can work at a lower weight. From my heaviest to lightest set ups, I spanned about a pound and a half difference.
There was a study that calculated a 4 pound weight around a person’s weight equated to about 4% more energy use. Plus the US Army has found that a) 1 pound on your feet equals about 5 on your back, and b) that 1 pound on your feet comes out to about 5% more energy usage, so c) we could extrapolate that 5 pounds on your back may also equal 5% more energy usage.
The point isn’t to be exact, but if we assume a continuing linear relationship, then that 1.5 pounds I saved equated to 1.5% less energy used, or thereabouts. That doesn’t sound like too much, but multiply that over each day I’m moving.
I was on Denali for 15 days. 12 of those days, I was in motion. On the average day in motion, I burned about 6000 Calories. 1.5% is 90 Calories, and that comes out to over 1000 Calories extra for the trip. To relate that to food, I would need more than half a pound of food to put that back.
I could also talk about safety margins. If one of my safety margins is my body’s ability to perform the required work, what would an increase of 1.5% mean to me?
And as much as I think the sleep system weight, alone, produces enough of a result to be worth it, if I start talking about getting lighter across all of those big ticket items, now we are talking about a 10 pound difference, or 10% energy difference, or 600 calories a day - or the equivalent of running for an hour or so after putting in my climbing work… every day.
Like the ice screws, the cumulative difference stops being small, and when we are talking differences of pounds… well, the advantages start to become obvious.
So, I encourage people to think about their sleep systems and to be willing to experiment to find something that works for them. It could make a big difference over the long haul of your adventures.
Finally, for the record - and as I state in the video - here are the gear recommendations I made to get to a 3 pound set up:
Therm-a-rest NeoAir XTherm inflatable sleeping pad