Information for consumers on the design, use,
maintenance and lmitations of


Even during summer nights cold weather can be expected. In mountainous areas, cold is even more common. Knowing how to properly use a sleeping bag can make the difference between a cold miserable night and a comfortable restful sleep till morning.Keeping warm in a sleeping bag is divided into three main parts; human components, environmental components, and your sleep system components.
Remember, your sleeping bag does not produce heat. It is only an insulator that slows heat being lost from your body. In cold conditions it is important to start the night warm. You will sleep comfortably if you maximize your body’s heat production and minimize heat loss.

1. Human Components
(a) Role of metabolism and body mass
Taking a short walk or light exercise is a way to increase metabolism by getting your muscles to generate heat. But do not work to the point that you will begin to sweat, this could cause the inside of your bag to become damp.
(b) Diet (protein, carbohydrates, sugar or hot beverage)
It is important to have enough to eat and drink before going to sleep. Your body will burn fats throughout the night and generate heat. A hot beverage with sugar just before retiring will warm you up so that your bag heats quicker. Sweet food will boost your metabolism and warm your sleeping bag’s insulation.
(c) Age / Physical condition
In general older people or people in “poor” health will have a lower metabolic rate and therefore, they will have a harder time warming their bag. In this case they should buy a warmer rated bag.

2. System components/Auxiliary products
Your sleep system includes more than just your sleeping bag. Other components that affect your warmth are a sleeping pad, ground cloth, bivy sack or tent. All of these items will increase your chances of having a warm night’s sleep by reducing the amount of heat lost through convection and conduction.
(a) Ground and ground pad, conductive surfaces
Using a ground pad made with an insulate foam will help prevent conductive heat loss between you and the ground. EVA pad is a major building block of foam and is a good conductor of heat.
(b) Cots, hammocks
The use of a cot or hammock presents a unique situation.
(c) Tent
The use of a tent or bivy bag helps to create another layer of dead air space and helps to reduce convective heat loss.

3. Clothing
Since the majority of heat is lost from your head, wearing a hat and resonable extra clothing layers, the more insulation, leading to a warmer sleep solution. The theory that sleeping naked is warmer may be fun, but it is no true.

4. Human/Environment Interaction
(a) Campsite selection / protection from the elements
Avoid camping in low areas where cold air collects. Moving air causes convective heat losses so camp sites should be sheltered from the wind. Be prepared for high elevations to cool quicker when the sun sets or goes behind clouds.
(b) Bag conditioning in the field
It is suggested to open up your sleeping bag as early as you can before sleeping. Giving your bag as much time as possible to fully loft will maximize its insulate value. Pull your bag out of its sack and shake it and fluff it to get air mixed into the insulation. Do this several times before retiring.

Manipulating bag features, adjusting insulation, controlling heat loss
Some models of down bags for instance are constructed with continuous baffles. In warmer weather move the insulation to the bottom of the bag and when you find the weather cooler than you expected, move more of the insulation on top of you provided you are using a good sleeping bag.

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