Thermal balance: If you feel hot, so heat generated by our body is equal to or greater than the heat lost to the environment around us. The heat is generated by metabolism. But, as we lose heat? It is given by:
Driving: on contact with a cold surface, our body begins to lose heat, because there is a search for the thermal equilibrium. In this case, we’re talking about especiallythe floor under our body.
Convection: we are constantly heating the air around us, creating a “micro-climate”comfortable. However, as this air doesn’t get trapped around us, any air circulation or movement makes this air is blow away, causing our bodies to warm the air around us again. This causes waste heat constantly.
Breath: The breath, the air needs to enter into our lungs to a certain temperature.So, to breathe a very cold air, our bodies lose heat to heat the air to pass through the respiratory system.
Evaporation: the sweat is a mechanism of reduction of body temperature. When the sweat evaporates, carries heat, causing the temperature is reduced. When we are sleeping in cold environments, the impact of evaporation for heat loss is too small.
Irradiation: our body is constantly radiating heat. Also does not have a big impact,but it’s always good to use a hat to sleep, since much heat is radiated by the head, once the scalp is very watered by capillaries. Therefore, sleeping bags to colderplaces always have a hood.
The two ways to lose heat more important to a person sleeping outdoors are conduction and convection.
For a comfortable night, we need a thermal balance, that is:
Heat generated = Heat Lost (by convection, conduction, respiration, evaporation and Radiation).
Choosing a sleeping bag via Campingtopgear.com: the choices begin on filling material of the sleeping bag,that is what will promote isolation and retain body heat, creating the “micro-climate” that heat loss by convection normally impossible. This filling can be synthetic fiber or feather.
Synthetic fiber: These fibers are hollow filaments, where the air is trapped and is this air which is used as a thermal insulator. Are manufactured through a process ofthermal consolidation and are silicone, to increase your power and filling with air compression, improving the thermal insulation. Below, some of its features:
Cheaper than the feather;
Its isolation is little affected when it gets wet;
Requires less maintenance.
Feather: also known Duvet (French) and Down (from English), are usually goose feathers. The deciding factor in feather bags is the quality of the same. This quality isexpressed by the ratio of feathers and small feathers, which in the case of the best brands, is 90/10 (90% and 10% feathers of small feathers), which is the proportion of highest performance.
The origin of feathers is also a very important factor. The birds that live in more severe climates have denser and larger plumes. So the feathers of geese from areasto the North of Europe have feathers of better quality than the domesticated geese raised in China.
Below, some of its features:
More expensive than synthetics;
Its isolation is very affected when it gets wet, so it is more suitable for places withdry climate;
Higher compression ratio (weight ratio x volume);
Maintenance more difficult (but nothing that can’t be done!).
The next choice is the format of the sleeping bag. Basically, there are rectangularbags and sarcophagi.
Rectangular bags: Are more used for camping and not for trekking or hiking moretechniques. Are also used by those who will spend the night in a lodge or shelter,where there is no need for anything too technical, and can be used as ground cover or blanket.
Sarcophagi: bags are the most suitable for trekking and hiking more techniques, especially in colder locations. The ideal is to always use a sleeping bag that literallyview you, because the more room left, more heat will be needed to heat the air to be in these spaces. As this type of sleeping bag comes with the format of the outline of the body, not much free space.
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