As well as giving you something comfortable to lie on, your sleeping mat provides vital insulation from the cold ground.
Unless you’re camping in very cold temperatures, you can actually lose more heat to the ground than to the surrounding air – up to three times more in some conditions! This makes a good camping mat absolutely essential. But how do you choose?
In almost all camping situations, the ground will be colder than the human body (that's you!). When you lie down, heat passes from your body to the ground by conduction. Your sleeping bag doesn't keep you warm in this situation as all the fill beneath your body gets compressed. This squeezes all the insulating air out and means that your sleeping mat is the only thing keeping you warm from below.
There are three different types of sleeping mat, each using a different method to insulate you from this conductive heat loss.
Foam mats are made from highly insulating closed-cell foam. This foam contains lots of tiny sealed-off air pockets which provide insulation from the ground below. Closed-cell foam mats have been around for decades and they’re still going strong even now; no self-respecting Scouts trip or Duke of Edinburgh expedition is complete without a foam roll mat hanging off the bottom of a rucksack!
Closed-cell foam mats are very lightweight and you can’t puncture them so they’re almost indestructible. The downside is that they can be a bit hard to lie on, and they’re so long (the width of the average human) they have to be strapped to the outside of your rucksack. This certainly makes squeezing through train doors a challenge! Some foam mats now use a folding ‘z’ construction to make them easier to pack. Other recent innovations include aluminium film coatings to reduce heat loss by radiation and 'egg box' constructions that trap pockets of still insulating air.
Pros: Bombproof, cheap, lightweight, excellent insulation
Cons: Not as comfy as other alternatives, bulkier and often need to be strapped to the outside of your pack
People often call this type of mat a Thermarest® (in much the same way we call vacuum cleaners: ‘hoovers’) but there are a huge range of self-inflating mats available now. Self-inflating mats use open cell foam (the spongey stuff you use to wash your car… sometimes… once a year maybe) wrapped in a hard-wearing outer fabric. When you open the valve, this foam springs back into shape, sucking in air and inflating the mat. Most mats inflate within 5 minutes or so, but you may need to top up the air with a couple of lungfuls. Generally speaking, the thicker the mat, the warmer it will be.
Self-inflating mats offer the best of both worlds. The foam inside the mat traps lots of still air for insulation, and they’re much more comfy to lie on than the classic foam roll mat. Self-inflating mats can vary from beefy car camping mattresses to ultralight backpacking mats with ‘die-cut’ foam to reduce their overall weight. It’s important that you store self-inflating mats flat with the valve open; storing them rolled up and compressed can stop them from inflating properly when you next get them out.
Pros: The best balance of warmth, weight and comfort, less effort to inflate at the end of the day than inflatable mats
Cons: Not as packable as inflatable mats, can be punctured, need to be stored flat with the valve open, heavier than other mats
With their tiny pack-sizes, inflatable mats are increasingly the favoured option of lightweight backpackers and space-starved bikepackers. The insulation is provided by still air within the mat’s chambers. Some brands use reflective foil, synthetic insulation and down inside these chambers for extra warmth, although this does push the price up significantly.
Inflatable mats are lightweight, extremely comfortable and pack down incredibly small. However, they’re the least durable of all the mat options and can be a little cold for anything other than summer camping (without internal insulation). They can also be susceptible to mould and moisture build-up which can cause your mat to delaminate (the layers start coming apart). Using a pump bag to inflate your mat and storing it flat with the valve open can easily solve that issue though.
Pros: Lightweight, comfortable and by far the most packable
Cons: Not as warm as other types (without insulated chambers), can be punctured on sharp objects, you need a good set of lungs or a pump bag!
Many people still swear by the old-fashioned airbed. But unless you want to spend your whole evening manning a foot-pump or actively enjoy carrying heavy sheets of rubber up mountains, they’re best left alone!
This will usually be the most important thing you think about when you’re choosing a sleeping mat. Think about what time of year you’re likely to use your sleeping mat and in what kind of climate. For colder conditions, you’ll definitely need an insulated, fairly thick mat. If you only a need a mat for the occasional summer bivvy, warmth is less important.
What kind of trips do you want to use your sleeping mat for? If you need to carry your mat on multiday backpacking trips or fit it inside bikepacking bags, weight and pack-size could be crucial. You definitely wouldn’t want to carry a 5kg Double Dozer the length of the Cape Wrath Trail! But if you only have to carry your mat from the car to your tent, weight and pack-size probably won’t be that much of an issue.
If you’re carrying your mat a long way, you’re probably prepared to sacrifice a little bit of comfort for less weight on your back/bike. But the longer the trip, the more important a good night’s sleep becomes. If you won’t be carrying your mat at all, you may as well opt for the comfiest car camping mattress that will fit in your boot – make that basecamp as luxurious as possible!
Getting a puncture in your sleeping mat miles from civilization could be a big problem without a puncture repair kit (all Alpkit mats are supplied with one of these for this reason). It can be hard to compare inflatable and self-inflating mats for durability as there are multiple different things which can affect it. That said, fabrics with a higher denier (thread thickness) will generally be more durable.
The mat shape will make a big difference to weight and pack-size but may also have an effect on its warmth and comfort. Mummy shaped sleeping mats are lighter and pack smaller but are easier to fall off. Three quarter length mats reduce weight and pack-size significantly but you might end up with cold legs in the night!
There are lots of things that can affect your sleep when you're camping, including how much you’ve had to eat and how… um… 'sheltering'… your shelter is. Remember that your sleeping mat is only one part of your overall sleep system, along with your sleeping bag and clothing. Choosing the right sleeping mat for the conditions is just the first step to guaranteeing a warm and comfortable night’s sleep.