The GO Outdoors Guide To Baselayers
The first part of the layering systems starts next to the skin, with a baselayer. The baselayer is designed to trap a thin layer of warm air against the body and it also works to pull sweat away from the skin, which is known as ‘wicking’.
There are 2 main types of fabric you can choose for a baselayer, Merino wool, or synthetic fabrics.
Merino wool is a natural fabric that is comfortable and odour resistant, but is a less effective fabric at wicking sweat. Merino is ideal for extreme cold conditions. Synthetics are lightweight and wicking alternative to merino, but are less efficient at resisting odour. However they do dry very quickly and also cost less than merino layer.
Whatever you choose- make sure you avoid cotton. Cotton soaks up sweat like as sponge and when it’s wet; it draws heat away from the body, which can cause hypothermia. (Hypothermia can be contracted even in ‘mild’ weather!)
A baselayer should fit closely like a 'second skin', an should be made from an appropriate wicking material which not only allows you to move freely, not chaffing your skin as you do so, but also allows you to transport moisture away from the skin.
Do Baselayers Prevent Sweat?
Baselayers do not prevent you sweating. Sweat is a natural response that is created during activity, it is released in order to keep you cool. By releasing excess heat and bodily salts the body attempts to cool you as your core temperature rises.
With 2 and a half million sweat glands on average on our bodies, these are all 'venting' areas on our bodies for dampness and moisture.
The sweat you produce varies from each individual, with any amount of 1 to 3 litres being produced during a day of activity. This is why it is so important to stay hydrated.
The sweat as a liquid is scentless, but can still stain. The odour comes from bacteria mixing with the sweat and the proteins within in, which produces a smell.
This is why many baselayers concentrate on using anti microbial properties on the surface, such as silver ion technology which breaks down the cellular wall of the bacteria to not prevent sweating, but to prevent the smells that can form on a baselayer.
Baselayers work by releasing this excess sweat into the fibres of your baselayer. The baselayer, if it is wicking, then draws this moisture away from your skin, where it is evaporated. This process ensures you maintain an optimum body temperature and stay cool and dry.
For this process to happen, the baselayer must be next to the skin, and must be made from a technical fabric, capable of releasing moisture, known as a ‘breathable’ or ‘wicking fabric’.
Baselayers are different from garments such as t-shirts because they never use 100% natural fibres such as cotton.
Although cotton feels comfortable, and can fit close to the skin, it is unsuitable as a technical layer as it soaks up moisture and holds on to it, preventing quick evaporation, leaving the wearer cold and uncomfortable.
Baselayers are essential for any form of outdoor activity in both cold and warm conditions and many baselayers are designed with inbuilt SPF (Sun protection factor). 100% SPF indicates the baselayer can protect from UVA, UVB and UVC rays.
Mesh areas are usually found in baselayers to add additional ventilation to your baselayer and zips and adjustable cuffs are common, allowing you to create open venting points to speed the cooling and drying process.
Wool is included in many baselayers because despite appearnaces, wool can work in the same manner as a technical synthetic. The fibres of the wool are important, and it is merino wool from merino sheep found in New Zealand that is typically used in technical clothing and baselayer construction.
Merino wool has a much smoother final finish than a standard sheep's wool, and the fibres are non abrasive and ideal for people with sensitive skin.
Wool works as a baselayer by absorbing the excess mositure, rather than passing it through a layer as with synthetics such as GORE-Tex. A wool baselayer holds 30% of it's own weight in water absorption before this reaches the skin level of the wearer, and throughout the process of absorption the natural fibre construction means that Merino Wool can remain breathable.
Wool is also a great natural insulator, holding heat within the fibres and distributing this warmth evenly, which makes Merino wool a good choice for a variety of climates.
Wool can perform well when wet for a certain time period, and is also comfortable and soft. It also typically fends off bacteria, which causes odour when combined with sweat for longer periods that similar baselayers made from synthetics.
However, synethtics typically dry off quicker than wool.
The most preferable option for a travel shirt is a fabric blend that consists of both a typical synthetic such as CoolDry, or polyester, mixed with a merino wool percentage for the benefits of both the fabrics.
Bamboo extracts, or carbon bamboo can be inclued in baselayers. A recent addition to technical fabrics, the use of bamboo is widespread because it is a sustainable resource.
In terms of capabilities, bamboo is manufacture to be very smooth and soft.
Bamboo drapes easily and sits close to the skin, making it an ideal fabric within a treavl shirt for moderate temperatures.
The draping oes sit fairly close, and some outoor enthusiasts have observed this fabric blend is too close for extreme temperatures.
However, in compasrison with cotton, or a similar natural fibre, excluding merino wool, bamboo is a performance fabric, able to dry off quickly and to wick away odors and bacteria.
Clean your baselayer after each use, and make sure it dries naturally, if possible to ensure any protective coatings are maintained.
Using a fabric softener can reduce the amount of wicking ability that the baselayer has, so if possible, handwash your baselayer using a specific cleaner.
A GO Outdoors staff member can advise you on the best washing method for your specific baselayer.
Harsh detergents should always be avoided because they strip the baselayer of it’s protective coatings.
Regular washing should take care of your baselayer and ensure your baselayer's longevity season after season.