DID YOU KNOW?
Rocks, hard-packed soil, and snow steal body heat faster than softer organic materials like forest duff and wood.

The ground is your cold, hard nemesis. You need a good sleeping pad to protect against it. With the right one beneath you, you'll keep heat loss at bay and sleep in dreamy comfort 'til the sun rises again. The trick is to figure out how much padding and warmth you really need.

Go Light, Sleep Hard
Ultralight pads weigh less than a pound but sacrifice comfort to save those precious ounces. The simplest is a thin closed-cell foam pad, such as the iconic "blue foam" pad or Therm-a-Rest Z-Lite. They are lightweight (10 to 14 ounces), inexpensive ($20 to $40), and hassle-free, but are also bulky and must be attached to the outside of most packs. Lightweight inflatable pads offer more comfort and compress to in-the-pack size, but are pricier ($75 to $150) and must be blown up and deflated, a minor inconvenience. Most sub-pound versions are only an inch thick; you'll need to inflate them tautly to prevent your hips from pushing through to the ground. Pads typically come in either a full-length (usually 72 inches) or short (48 inches) version, which can save weight at the expense of your feet and lower legs.

Go Big, Sleep Deep
A wide range of inflatable pads hovers between 1 and 2 pounds, offering considerably more comfort for the extra heft and bulk. They are at least an inch and a half thick, which allows you to slightly underinflate them without risking your pointy parts touching the ground. This creates a luxurious, mattress-like effect that effectively cradles more of your body. Many pads are much thicker, up to several inches of sleeping cush. The truly luxury-minded can opt for pads that are both longer (up to 77 inches) and wider (25 inches instead of the standard 20), though they will easily exceed 2 or even 3 pounds. Expect to pay $75 to $200 for a pad in this category.

Warmth Factors
Once you've determined your desired comfort level, next consider warmth. Sleeping bags don't provide any protection from the cold ground; your weight effectively compresses the bag's insulation to nothing. It's the pad that does the work. Like any insulation, sleeping pads provide warmth by trapping dead air in place. A range of materials is used to accomplish this, including closed- and open-cell foam, synthetic fibers like Primaloft, and goose down. In order, each is increasingly compressible, lighter weight, and expensive. As a general rule, thicker pads will be warmer than thin ones, though the type of insulation also plays a big role. For this reason, most manufacturers list an "R-Value" to indicate a pad's relative warmth.

A higher R-value indicates a greater resistance to heat flow and thus a warmer pad, especially when you're sleeping on very cold or frozen ground. Keep in mind, however, that no industry-wide standard exists for testing R-values. Each manufacturer determines, and labels, its pads according to its own methods. For this reason, R-values should be considered only a guideline among styles in the same brand rather than a tool for objectively comparing every pad out there. As a general rule, an R-value between two and three will be adequate for three-season campers; cold-weather adventurers will want an R-value of at least four.

All Shapes and Sizes
A variety of pad permutations exist. Some manufacturers produce sleeping pads specifically designed for women and children. They are essentially the same as any other pad, though the lengths vary to account for gender and age differences in height. (A women's long, for example, is usually 6 inches shorter than a men's.) Women's pads also feature more insulation beneath the torso and feet. Extreme ultralighters can choose 36-inch models, just enough to provide coverage and insulation in the crucial shoulders-to-hips region. There are even some closed-cell foam pads that feature a small inflatable section in the middle for extra comfort. Whatever you choose, sleep tight, sleep right, and enjoy the night!