Choosing a Sleeping Mat
Why put a mat under your sleeping bag when sleeping outdoors? Sleeping mats cushion you, but more importantly, they block thermal transfer between you and the ground. Your sleeping bag, how advanced it may be, could not preserve all your body heat if it is in direct contact with a cold surface.
Your sleeping mat should prevent this. It consists of either closed cell foam or is inflatable to use air as an insulator. Both methods work, yet self-inflatable mats like our mountain mats offer better insulation. With die cut they are also lighter and more compact.
When choosing a sleeping mat, you have to consider your activity and what will be most important. A thicker mat will have a greater thermal resistance rating (it will be warmer!), but this also means you may have to compromise with extra weight. The most important things that will affect your choices are: R-rating (thermal resistance rating - the higher the number the warmer it is), packed volume, and weight.
You take sleeping mats for two major reasons: cushioning hard ground and insulation against cold from below. But what size and shape do you need?
Length and width of your mat should be selected according to your body. On a standard mat you can rest your entire body. It will be more comfortable but heavier than a small mat. If saving weight is an important issue, ensure you at least fit your hips and shoulders onto a small mat.
If you tend to toss and turn in your sleep, you might experience a cold awakening - ending up beside your sleeping mat. A wider or mummy shaped mat like the MD Pro will help solve this problem.