A Brief History of Sleeping Bags
Long before the advent of the sleeping bag, frontiersmen – indeed anyone sleeping in the great outdoors – would use one or more animal hides to provide warmth during the nights.
Some tribesmen still make use of animal hides even today.
Even after the advent of hand-spun threads and hand-woven fabrics, a combination of hides and blankets were the only real options when it came to night time coverage in the great outdoors.
The first known design for what we would recognize today as a Sleeping Bag was patented by a mail-order pioneer named Pryce Pryce-Jones in 1876.
He sold some 60,000 of these to the Russian Army, and also supplied a large number to the British armed forces as well.
His design included an air-tight, inflatable pillow; quite staggering when you consider we’re talking about the 19th century. The civilian-sold units came without the addition of this pillow.
Things have certainly changed since then.
Mixtures of natural and synthetic materials enable us to choose from a vastly diverse selection of sleeping bags, designed to cover a near-equally vast range of conditions.
We tend to think of extremely cold environments when thinking about sleeping bags, but a sleeping bag is every bit as important in hot climates as it is in the cold.
From scorching deserts, to freezing mountains, and everything in between; there’s a sleeping bag designed for quite literally every conceivable climate on Earth… and even beyond.
That’s not a typo… there are actually sleeping bags designed for use in space.
For use on the MIR and International Space Stations, the Russians produce a sleeping bag like the one you see here.
It’s designed to aid the body in regulating its optimal temperature in conjunction with the life support systems aboard man-made space-fairing vessels and facilities.
"Down" and "Synthetic" - what does it mean?
Generally speaking, there are two fundamental categories of sleeping bag: “Down,” and “Synthetic.”
A “Down” sleeping bag utilizes feathers from Ducks and/or Geese to provide its insulation.
The advantage of down-filled sleeping bags is that they are significantly lighter than an equivalent “Synthetic” sleeping bag, and can be compressed to a smaller pack size.
One significant negative consideration when it comes to down-filled sleeping bags is that, should they become wet such as through rain, they lose virtually all of their insulation value.
This means you have to be extremely careful to keep a down-filled sleeping bag dry at all times.
“Synthetic” sleeping bags are very different.
Synthetic sleeping bags tend to retain some (if not most) of their insulating value even when damp or wet to some degree.
On the downside, Synthetic sleeping bags tend to be significantly heavier and bulkier than their equivalently-rated down-filled counterparts.
Essentially, it is down to you to decide for yourself whether you value lighter-weight and a smaller pack size, or insulating performance should the sleeping bag somehow become wet.
A Bag for a Season
Whether you opt for a down-filled sleeping bag, or a synthetic sleeping bag, you need to consider that a one-bag solution – regardless of the bag’s rated thermal range – is only really perfect for whatever season happens to fall within the middle of its thermal range.
Put simply: a Winter-rated sleeping bag is only going to be optimally comfortable during winter – cold – conditions.
It is very likely to be uncomfortably warm during the hotter seasons, and so you’re likely going to end up buying different sleeping bags for different seasons.
What use is a cold-weather-specific sleeping bag during the warmer seasons? That’s right, none!
From my perspective, purchasing cold-weather-specific sleeping bags is a waste of money, and a waste of kit.
Sure, if you happen to live in the Arctic or Antarctic, where it’s freezing cold year-round, then it makes sense to own cold-weather-specific sleeping bags.
Fortunately, there is a better way!
A Bag for all Seasons - The Modular Sleep System
A “Modular Sleep System” is, simply put, any sleeping solution comprising multiple – thinner – layers to, once combined, provide warmth and comfort to an Arctic-level low temperature extreme.
Such solutions can be purchased as a product, or assembled by yourself.
Regardless of whether your Modular Sleep System is purchased as a product, or self-assembled, they each comprise three essential components.
First, we have a breathable-but-waterproof (e.g. “Goretex”) bivouac (or “bivy”) bag layer.
This forms the outer-most protective layer, principally for keeping your sleep system dry during wet conditions.
Second, a “three-season” rated, medium-density sleeping bag
This would be suitable for use in conditions where it’s too cold for a summer-rated sleeping bag, but not quite cold enough for a winter sleeping bag to be comfortable.
Third, a thin, summer-rated, low-density sleeping bag.
This would be suitable on its own only for use during the summer months, where nights tend to be quite hot.
The Modular Sleep System shown throughout the photos in this article is the “US GI Modular Sleep System” from Tennier Industries.
This system used to be issued to American forces as their defacto solution for sleeping in any climate on Earth.
It has since been replaced by a newer version of, fundamentally, the same basic system; only with a few improvements made specific to the needs of military personnel.
Modular Sleep Systems provide greater flexibility when it comes to changes in climate.
The one system can be used to ensure an ideal degree of comfort at any temperature, at either extreme or anywhere between.
A further advantage is one of redundancy, where individual layers of your Modular Sleep System can be packed into your kit in separate drybags.
This means that, should one layer be compromised in some way (or even lost) you retain any other layers packed separately within your kit.
While losing any one layer of your Modular Sleep System may significantly reduce your level of comfort, you have to agree that surviving an uncomfortable night is certainly preferable to death from hypothermia.
Best of all, you can use a down-filled sleeping bag for the thinnest component layer of your own Modular Sleep System, then use a synthetic sleeping bag for the outer layer, protecting the down-filled bag from becoming wet; with or without the use of the outer-most waterproof bivy bag.