Sleeping mats provide 2 vital benefits: cushioning and insulation. Cushioning might seem like a pad's most useful function, but often more important is its ability to insulate your body from cold surfaces.

How Do Sleeping Mats Work?

Sleeping mats insulate the same way that sleeping bags and clothing layers do. They trap and hold a layer of dead (non-circulating) air between your body and the cold (in this case, the cold ground). Your body gradually warms this layer of dead air and it becomes an insulating barrier.

Beneath you, though, a sleeping bag's heat-trapping loft gets compressed to almost nothing due to the weight of your body. As a result, you need a pad to buffer you from heat-depleting contact with the cold ground (this is known as "conductive" heat loss). The insulative performance of a pad depends upon how much air it holds inside and how free that air is to circulate.

Types of Sleeping Mats

Air Mats

These mats use air for comfort and must be manually inflated. Some models integrate foam, insulative fill or reflective materials to increase warmth.

Pros: Comfortable and lightweight. Fine for backpacking or camping in warm conditions; insulated models can be used year-round.

Cons: Can puncture, though field repairs are not difficult. Noninsulated models offer poor insulation due to free circulation of air inside.

Self-inflating Pads

Pioneered by Therm-a-Rest mats, these offer a combination of open-cell foam insulation and air. Open the mat's valve and air fills the vaccuum. These mats are wrapped in air-tight, waterproof nylon shells. Popular with backpackers, a few of the thickest models are better suited for car campers.

Pros: Comfortable; excellent insulation; firmness is adjustable; very compact when rolled up.

Cons: Heavier than simple foam pads and more expensive. Can be punctured or ripped, though field repairs are not difficult.

Foam Pads

These basic backpacking mat feature dense foam filled with tiny closed air cells.

Pros: Lightweight, inexpensive and durable; excellent insulators; won't absorb water.

Cons: Less comfortable. Relatively stiff and firm, so they tend to be bulky.

Air Mattresses

These car-camping mattresses use air for comfort and are much thicker than foam pads. They are as close to a real bed as you can get and are usually sized to take regular sheets.

Pros: Very comfortable. Easy and quick to inflate with a pump. Suitable for car or boat camping, or as a guest bed at home.

Cons: Relatively heavy and bulky. Pump required for proper inflation. Can puncture or leak. No insulation; for mild conditions only.

Choose a Mat Suited to Your Style

Your mat decision can be narrowed quickly by considering your type of travel.

• Minimalists and long-distance hikers: If you seek the lightest possible pad, pick a basic foam mat or a "short" or "3/4 length" of a self-inflating or air-mat model. Low weight and a small packed size override all other concerns.
• Backpackers: If you prefer a bit more comfort, compare pads with greater thicknesses and durability. The tradeoff, of course, is a moderate increase in weight.
• Family campers, boat campers, car campers: For you, size and weight are not limiting factors. You are free to choose a thicker, larger mattress for more luxurious sleeping comfort.
• Winter campers: Camping on snow requires more insulation. Suggest the use of 2 pads: a self-inflating or air mat atop a closed-air-cell foam pad. The foam pad adds insulation and offers insurance in case the inflatable mat is punctured.

Compare the Specs

Length: At a minimum, your shoulders and hips need to fit on a mat. Regular (typically 72" long) and long (from 75" to 78") mats will insulate your legs and feet—a big plus on chilly fall and winter trips. A short or 3/4-length mat (usually 47" or 48") weighs less and packs smaller.

Width: Nearly every mat offers a standard width of 20". If you tend to roll around a lot, you may want a width of 25" or 30" that's found in some large sizes. Tapered designs reduce volume a bit and pack smaller.

Women's mats: These mats are shorter (66" is typical), with added insulation at the hips and feet where women need it most.

R-value: Insulation is measured according to its capacity to resist (that's the "R") heat flow. The higher a mat's R-value, the better you can expect it to insulate you from cold surfaces.Thicker pads generally offer higher R-values.

Eco-friendly pads: A growing trend is mats made with recycled foam or shell-fabric materials.

Try Before You Buy

• How much cushioning (thickness) you need to be comfortable
• How long and/or wide you want your mat to be (many models are cut short to save weight and packing space)
• How quick and easy the mat is to inflate, deflate and/or pack away.

Consider the Extras

Finally, consider any additional mat features. These include multiple air chambers (for a custom adjustment), built-in pillows (for comfort), textured mat surfaces (for better insulation, less slip and more comfort) and tapered mat shapes (for less weight and bulk).