— There is great variation between individuals and between the sexes regarding the conditions necessary for a good night’s sleep.
— The primary source of warmth while sleeping is your body furnace (i.e., metabolism); tents, sleeping bags, clothes, pads, etc., provide no warmth by themselves.
— It's much harder to get warm than to stay warm.
— Keeping the core warm will go a long way to warm the extremities.
— Between going to bed at night and arising the next morning, there is often a large shift in the factors affecting a good night’s sleep: heat generating metabolism gradually slows down; ambient temperatures usually drop; sleep is deeper early on and lighter towards morning. The ideal is to have a flexible sleeping system that will handle these nightly variations.
— The minimum sleeping system should include an insulating sleeping pad, a sleeping bag or quilt, an adequate pillow arrangement and an adequate shelter for the conditions. Don't short-change these basic items.
— What you have under you is as important as what is on top of you; don't hesitate to double up pads, especially under your body core.
— The ideal is to do a pre-trip organization of several different sleeping systems that will cover a wide range of conditions, then select the system to fit conditions anticipated for the specific trip.
— Even though being warm enough is usually the primary concern, being too warm is also a serious problem. Being too warm will cause sweating which will dampen and lessen the effectiveness of your insulation when temperatures drop.
Above is my take on the most important principles underlying an effective sleeping system. Would you add to or subtract from this list?
For numerous practical suggestions that utilize the above sleeping system principles, click on this article “Good Night’s Sleep in the Backcountry.”