Many people underestimate the importance of having insulation underneath them when spending time in the outdoors. But anyone who has done camping or hiking in even cooler weather knows that insulation between you and ground it Is critical.
In most scenarios, this insulation is provided by a sleeping pad. A sleeping pad is made of foam or an inflatable material and provide the layer between you and the cold ground. Even in moderate temperatures, the earth remains cool. Since the mass of the soil and rock underneath you at any given time is so great, there’s no way you can actually warm that up with your body heat.
Conductive heat exchange
This is called “conductive” heat loss. If you’ve ever sat down directly on the surface of snow, or on a cold rock, and felt the chill began to seep into you, you have experienced conductive heat loss. The same phenomenon explains why grabbing a cold metal railing begins to chill your fingers rapidly. Conductive heat loss is very dangerous in a survival situation.
Conversely, conductive heat gain can be dangerous as well. The extreme version of this phenomenon occurs when you grab a hot pan off the stove and burn yourself. But the same principle applies in hot and desert environments in survival situations. Laying down to rest on an extremely hot rock that has been baking in the sun can quickly add a great deal of extra heat to your body, leading to heat exhaustion or heat stroke. Using a pad or other material to insulate you from the hot surface is a sensible precaution.
About sleeping pads
The most basic type of sleeping pad is simply a section of closed-cell foam. These foam pads are lightweight, affordable, durable, and effective.
They also have the advantage of flexibility. A foam pad can serve as a great sit pad while cooking. In an emergency, it can be cut into multiple pieces and repurposed as a splint for an injured limb. Parts of a foam pad can be used for countless things, including custom cheek rests for a rifle, sit pads for hunting stands, simple armor padding that can be inserted inside clothes, or a floatation device.
The second main type of pad is the inflatable pad. This pad is essentially a flattened air bladder with a valve for inflation. The air (along with foam or, more rarely, down or synthetic “puffy” insulation) serves to increase the warmth of the pad and provides a comfortable sleeping surface. For many years this market was dominated by the “Therm-a-rest” but now many other manufacturers have similar products available.
These pads are comfortable, but their main drawback is durability. If your pad is punctured, insulation and comfort declines notably. Patch kits are available, but that’s another piece of gear to carry
Increasingly, pad manufacturers are providing “R-value” insulation ratings on their sleeping pads to give you an idea of how warm they will be. Multiple sleeping pads can also be stacked to increase the insulation value of a pad.
Single pads vary from an R-value of about 1 to about 10. The higher the value, the colder conditions that pad is suitable for.
Many experienced outdoorspeople choose a hybrid approach during cold seasons. By using two pads, you get a warmer bed. If you choose one inflatable pad and one foam pad, you can also strike a nice balance between comfort and durability.
Improvised sleeping pads
Several alternatives to traditional sleeping pads do exist. You can also improvise sleeping pads of many other materials, both natural and man-made. The traditional method of staying off the ground involves cutting fresh boughs from nearby trees to create a “mattress” of sorts. Done correctly, this can provide significant insulation.
Other natural materials that can be heaped or mounted to create a sleeping platform include:
These materials should be as dry as possible to provide insulation. When wet, they lose much of their insulating value. However, wet pad materials may be better than nothing.
When it comes to man-made materials, you have many options as well. Many homeless people use cardboard and newspapers as an insulation layer between themselves and the ground. As long as this material is kept dry, this can be very effective. Almost any other material can be used here. Paper, extra clothing, scraps of fabric, even something like books an additional layer of insulation between you and the earth.
The bottom line here is pretty simple: keeping insulation between yourself and the ground is almost always essential. Make sure to plan for this when preparing yourself for survival and emergency situations. I recommend including a sleeping pad in your bug-out-vehicle and extended duration bags.