A sleeping bag is an insulated, lightweight, portable bedding designed for outdoor sleeping activities such as camping, hiking, and climbing. It is essentially a quilt that can be zipped up to form a tube, offering a cozy sleeping environment. The construction of a sleeping bag includes an outer layer, an inner lining, and a filler for insulation. The main purpose of a sleeping bag is to provide warmth and protect against cold weather by trapping air inside, which is then warmed by the body’s natural heat.

When selecting a sleeping bag, important factors to consider include the temperature rating, shape, size, fit, and insulation type. Sleeping bags are typically categorised by their temperature ratings, with most designed for use in conditions ranging from 10 to 50 degrees Celsius, catering to the popular summertime camping. Models rated for 10 to 35 degrees are ideal for spring, fall, and mild winter conditions, while bags rated at 10 degrees and lower are suitable for cold winter weather.

Table 1 Thermoregulation of Human body

Factors Influencing Thermo-regulation of Human Body

Slim or Heavy: People with greater fat reserves have better insulation potential. People with greater muscle mass also produce more heat and do not cool down as quickly. Slim people usually consume as many calories as they burn.

Gender: Women tend to generally feel cold faster than men. The average comfort value for a standard female is 5o C higher than for a standard male.

Age: Metabolic rates tend to slow down as one becomes older. The lower the metabolic rate, the less body heat a person generates.

Condition: People who are physically fit and often spend time outdoors are less susceptible to cold. In addition, when a person is exhausted their body generates less heat as well.

Energy Input & Consumption Before Going to Sleep: The amount of energy or warmth generated while sleeping is affected by a person’s activities and energy input.

Sleeping Bags – Construction

Sleeping Bags comprise an outer layer, a filling, and an inner lining. Within the sleeping bag’s shell are a number of chambers called Baffles. Baffles contain the down used to insulate. The better their design, the better the performance of the sleeping bag. To insulate efficiently the down has to loft, which means to expand as it traps warm air. Too much space in the baffle is inefficient as the down disperses. Too little space constricts the down and it cannot loft fully. There are a number of different types of baffles. All have advantages and disadvantages, which vary depending upon the type of product.

Table 2 Types of Baffles

Sleeping Bags – Materials

Table 3 Properties of Outer Layer/Cover fabrics

Table 4 Filling / Insulation Layer Material

Table 5 Bag Liner Materials

Table 6 Shapes of Sleeping Bags

Conclusion

A sleeping bag is an essential textile product that is aimed at protecting people in cool or cold outdoor environments. They are widely used in field training, rescue and relief work and are also becoming common equipment in travelling and recreation for ordinary people. Sleeping bags serve as an important protective textile product for human body while sleeping under cool or cold outdoor environments. A sleeping bag should allow the wearers to sleep for four to eight hours without feeling cold under the bags’ operating temperatures.