A high-quality sleeping bag will not let you freeze even in the most extreme trip
Don't think that a sleeping bag is just a substitute for a blanket. A hiker is not always able to choose a dry and warm place to spend the night. This means that the sleeping bag must meet certain requirements. In particular, it should be light, protect from cold, dampness and moisture. Different types and models of sleeping bags help to cope with these adversities to varying degrees.
Depending on the intended purpose, sleeping bags can be shaped like a blanket or a cocoon (trapezoidal). It's easy to guess that at lower temperatures a 'cocoon' is used: a person is closed from all sides in it, unlike a blanket which is simply covered with. Such a sleeping bag narrows towards the bottom and widens towards the top. Because of this shape, heat is better retained. This is especially important if children will sleep there. After all, children's overalls although they protect from cold, additional measures are needed at night.
But shape is not the only factor affecting the level of comfort in a sleeping bag. Much depends on the filler. As is known, it can be both natural and synthetic. The natural filler is most often goose down, and the synthetic is sintepon or holofiber. Previously, cotton wool was also used for these purposes, but today it is no longer relevant.
Which filler is better? It is believed that natural material – goose down – most effectively resists cold. Nothing better than it has been invented yet by sleeping bag manufacturers. But synthetic materials are easier to produce and cheaper. Also, eider down is used among natural materials for stuffing sleeping bags. Its cost is very high, as such down is collected by hand in bird nests. It is used only for individual custom sewing of sleeping bags.
The most popular are sleeping bags with synthetic fillers – sintepon, ThermoLoft, 3M Thinsulate and others. Their advantage is that they weigh little, compress easily and easily return to their original shape, and also dry quickly. The main disadvantage of synthetic materials is that they do not tolerate washing very well, partially losing their properties.
For hikes in the forest and similar trips, when the air temperature remains within a positive range, sleeping bags with one or two layers of sintepon are used. If frost is expected, then sleeping bags with inserts are chosen: one sleeping bag is inserted into another. Due to the air layer that forms between them, additional thermal insulation is provided. In such sleeping bags it is comfortable even at -20 degrees. Obviously, the volume of such equipment is not small, so it is not very convenient to transport anywhere.
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