As hackneyed as this old proverb may be, its relevance is indisputable. For as all of you outdoor enthusiasts know, a good or bad night’s rest can play a significant role in determining your performance and overall well-being in the great outdoors. If you toss and turn at night, feel every little pebble through your sleeping mat or simply freeze your tail off, that’s usually where the outdoor fun stops. Not even the most beautiful of tent pitches could cheer you up!
Imagine finding out in the middle of a multi-day trip that you’ve packed an uncomfortable or poorly insulated sleeping mat. It doesn’t get much worse than that, does it? Anybody who’s ever laid on an utterly useless mat in icy cold conditions knows how energy-sapping and unpleasant it can be, not to mention how harmful to your health.
But, how would you go about choosing the best sleeping mat? Is there an all-purpose mat?
Things to bear in mind
First, ask yourself a couple of basic questions: what are the temperatures going to be like where you’re going? How will the mat be carried and how much comfort do you need?
All these factors play a significant role in selecting the appropriate sleeping mat. In terms of temperature, there is something call an R-value, which allows you to compare sleeping mats relatively easily.
The R-value indicates the thermal resistance of a material (similar to the formula symbol “R” for electrical resistance, from the Latin resistere, to resist). It is thus the reciprocal of the so-called thermal conductivity or heat transfer coefficient of a body (physical formula symbol lambda (λ), which indicates the ability to conduct heat.
It is therefore true that if the heat transfer coefficient λ :
- high = poor insulation,
- low = good insulation
Conversely, for our R-value (i.e. thermal resistance), this means:
- the higher R, the better the insulation,
- the lower R, the worse the insulation.
So: the higher the R-value, the better the insulation of the selected insulating mat. For insulating mats, the specified value always applies to the complete mat; the outer material and filling are used as a total unit for measurement.
Comparability of the R-value data through the F3340 standard
Apart from that, one problem with the specification of the R-value was for a long time that there was no standardised determination procedure for this, but that different manufacturers each did their own thing. Since the beginning of 2020, however, the American Society for Testing and Materials (ASTM) has issued the F3340 standard, which is intended to enable good comparability of the R-value data of different manufacturers.
The procedure (outlined in simplified form): the material to be tested is placed between two plates, whereby the lower plate remains cold (and simulates the ground), while the upper plate is heated to human body temperature. The energy required to maintain the (body-warm) temperature of the upper plate is now measured; this in turn yields the R-value. However, since the measurement is made under laboratory conditions and is supposed to correspond to an average person who is sensitive to cold, the result cannot be regarded as an absolutely valid categorisation, but rather as a rough guideline. This is all the more true as not all relevant parameters (e.g. inflation pressure for air mats, number of test cycles) have been finalised yet.
In the following, the R-values with associated minimum temperatures and the corresponding use are summarised in a table as points of reference.
|R-Wert||Minimum temperature||Range of application and seasons|
|1||+7°C||Summer +-1-2 months, depending on mildness of temperatures|
|2||+2°C||Spring to autumn, but without ground frost|
|3||-5°C||Suitable all year round (with mild winter)|
|4||-11°C||Suitable all year round|
|6||-24°C||Winter, mountaineering, alpine|
|7||-32°C||For extreme temperatures; expeditions (e.g. arctic areas, high mountains)|
|8||-38°C||For extreme temperatures; expeditions (e.g. arctic areas, high mountains)|
|9||-45°C||For extreme temperatures; expeditions (e.g. arctic areas, high mountains)|
|10||-50°C||For extreme temperatures; expeditions (e.g. arctic areas, high mountains)|
Transport and comfort
As mentioned above, you should think about how the mat is going to be carried. If, for example, you don’t have much room in your pack and are looking to go light, then you should focus on completely different mats than a skier who is planning on pulling a pulk.
And, of course, we can’t forget your personal and very subjective perception of comfort. If you’re more modest and fancy travelling with a light pack, then a lighter and thinner sleeping mat will be more appropriate. Some people even take a very short and small mat along that primarily protects their upper body. In this scenario, your legs would rest on your pack or clothing you brought with you.
If you tend to sleep on your side, toss and turn at night and always feel totally knackered, then I would recommend getting a thicker mat with a thickness of at least 5-6cm. These mats won’t allow your hip to bottom out, and you won’t be able to feel every little pebble through the mat.
Don’t be left out in the cold in the winter – or in the summer for that matter
Out of all the seasons, I’d say that winter has a special status. So, when selecting an inflatable sleeping mat for winter, you should keep the following in mind. Inflatable sleeping mats can be either manually inflated (using your mouth) or self-inflating, with the latter allowing for better overall inflation. In very cold conditions, however, blowing up a mat with your mouth can lead to water condensation getting into the interior and subsequently freezing inside the mat. Seeing as condensation negatively impacts the mat’s thermal efficiency, traditional and more resilient sleeping mats and mats insulated with down or synthetic fibres that include a built-in hand pump or pump sack are used more frequently in the wintertime.
For winter trips, the combination of a traditional sleeping mat with a self-inflating mat has proved successful, as this combo provides both protection from the cold and plenty of comfort. Speaking of warmth and comfort, in Scandinavia you’ll also see reindeer fur on the outside of rucksacks, but these furs are not only heavier but also tend to shed, not to mention they’re not available at Alpinetrek, nor will they be in the foreseeable future.
Swapping your mouth for a pump or a pump sack is recommended for the summer as well. Why? Well, the air you breathe into your mat can lead to a build-up of algae, which will eventually end up ruining the mat and its insulating properties.
What kind of mats are there and where can they be used?
Foam sleeping mats
For example: the Therm-a-Rest Z-Lite
R-value: 1.7 / Thickness: 2mm / Weight: 410 g
Foam sleeping bag are the traditional sleeping mats. They are reliable and pretty unsusceptible to punctures. Even if you accidently stand on it with your crampons on, it shouldn’t be problem. High-quality sleeping mats are made of a closed-cell foam, such as Evazote. This material is very tough and resilient, won’t go flat and insulates well. It is available in a variety of thicknesses.
Ideal for winter tours; if you need the mat to be very tough and resilient; very versatile, if it needs to be –for example, you could make an insole for your shoe or padding for your rucksack out of it.
For example the Therm-a-Rest NeoAir Xlite
R-value: 4.2 / Thickness: 6.4cm / Weight: 460 g
For the last couple of years now, these air mattresses have been taking the market by storm. But, the only thing they have in common with the originals now is that the airtight envelope is inflated into an air mattress with several chambers.
For these mats, extremely lightweight and durable material is used. Depending on the construction, the mats feature a baffled internal structure that provides stability and support. Plus, it has heat-reflecting material which traps air and thus prevents a loss of warmth.
Perfect for those who want something lightweight and packable; the thickness makes it very comfortable; considered by some to be somewhat less resilient; easy to repair – patch it and it’s ready to go.
Filled air mats
For example the Exped Dura 6R
R-value: 5.8 / Thickness: 7cm / Weight: 850 g
Similar to the “regular” air mattresses, these mats feature airtight fabric with baffles filled with down or synthetic fibres in order to increase their thermal efficiency. Despite how light these mats are, they are exceptionally warm. Plus, they’re extremely compressible.
Perfect for trekking tours where comfort is a must; suited for winter tours (an integrated pump or pump sack makes inflating easy); very well insulated.
Self-inflating sleeping mats
For example the Therm-a-Rest ProLite Plus
R-value: 3.2 / Thickness: 3.8cm / Weight: 650 g
Self-inflating mats are produced by several companies in several varieties. Therm-a-Rest invented a line of self-inflating mattresses in the 1970s and is now basically synonymous with self-inflating sleeping mats. These mats consist of an airtight envelope filled with a sheet of open-cell foam. When a valve is opened, the mat fills itself up with air. Then you simply close the valve – that’s it.
However, the term self-inflating should be taken with a grain of salt, for most mats require you to use your mouth to blow more air into the mattress to increase firmness. Still, it is much quicker and easier than inflating an air mattress.
To pack the mat, all you have to do is open the valve and roll up the mat tightly to force the air out and then close the valve. Depending on the mat of your choice, you’ll be able to get it quite small.
Perfect for trekking tours; great balance of comfort and thermal efficiency; depending on the model, very robust; easy to repair – some patches and Seam Grip and that’s it!
Self-inflating mats in detail
How to operate
Although the term self-inflating mat sounds somewhat technically complex, the actual function is quite simple. Inside the mat is a special PU foam. This is provided with open cells. When rolled up, the foam is extremely compressed. If you now unroll the mat, the foam expands. Opening the valve also creates a vacuum, which sucks air into the pores of the foam from the outside inwards. In this way, the sleeping mat inflates by itself, so to speak, and increases in density and thickness. Of course, the valve must also be closed again after the mat has fully inflated, otherwise the air will escape again when you lie down on it.
Additional air regulation options
As with mattresses, some people like it a little harder, others softer. Therefore, the hardness and thickness of a self-inflating mattress can be adjusted individually. The ground conditions are also decisive for this. To get more air into the mat, simply blow air through the valve or an additional mouthpiece.
However, when adding air from your mouth, you should always bear in mind that moisture and bacteria can penetrate the inside of the mat. In the worst case, this can attack the material and damage the mat in the long run. Moisture can cause moss to form inside the mat, which not only causes the foam to stick together, but also reduces the insulating performance of the mat. Another disadvantage of moisture in the mat: it can freeze in the mat at low temperatures and again reduce the insulating performance.
With mats that contain down for insulation in addition to their foam (e.g. from Exped or Mountain Equipment), you should generally avoid getting moisture in the mat, as the moisture will stick the down together and cancel out the insulating properties.
If you want to prevent moisture from getting in the mat, there are different systems for manually filling the mats with air without using your mouth. These can be integrated pump systems, for example, or systems in which the pack sack of the mat serves as a bellows. The systems vary greatly from manufacturer to manufacturer.
If, on the other hand, you want the mat to be a little softer, simply let as much air as you want escape through the valve.
The next morning, you will need to stow the sleeping mat in a compact way, but first you need to let the air out. This works just as easily as with an air mattress: open the valve and fold the mat two or three times and press the mat. Then, close the valve and roll up the mat from the foot end. The remaining air, which is still inside the mat, will collect at the upper end. By opening the valve again, this air will also escape. Finally, the close the valve again and store the mat away for transport. Ideally, you would keep it in a rolled shape. Use a stuff sack to transport the mat and protect it.
What do the different thicknesses mean
A clear distinction is made between the individual thicknesses of the sleeping mats in the comfort range. There are mats ranging from 3 cm to 10 cm thick. A thickness of 3 cm should really only be taken if it is a small tour, because it is less comfortable. However, these mats have an extremely small pack size. A thickness of 4 – 6 cm is better. Combined with a high-quality sleeping bag, a pleasant night’s sleep can be achieved. Sleeping mats with a thickness of 10 cm or more are the most comfortable. However, you should always bear in mind that the pack size increases depending on the thickness.
As is true of almost every product, there is a variety of accessories to go along with sleeping mats. Of course, some are more practical than others.
Those definitely worth mentioning are: the very important repair kit, the abovementioned pump and pump sacks as well as sleeping mat covers to make you feel at home and Vaude’s Navajo Sheet, which makes your camp into a double bed and is compatible with sleeping bags from the Navajo series.