The concept of ‘layering’ is key to choosing the correct clothing for outdoor sports and activities throughout the seasons. Unless you wish to confine your riding or running to sunny days only, or are lucky enough to live in a rain-free part of the world, you will need to invest in a selection of clothing that helps keep out the elements while at the same time allow heat and moisture generated by exertion to escape.
As the name suggests, base layers are intended to serve as the foundation of your layered wardrobe, and are thin, form-fitting garments worn next to the skin. Base layer garments serve two purposes – to keep you dry by transporting moisture away from the body to the outer surface of the cloth (a process known as wicking), and to keep you warm in cold conditions by trapping a layer of air against the skin, which warms up to provide insulation.
The type of base layer you choose will depend on the conditions you are active in and how important each of the above is to you – a light, sleeveless mesh base layer, for example, will aid moisture management in hot weather, while the thermal properties of an insulated, long-sleeve base layer will keep you warm in winter conditions.
Read on for more information about the types of base layers that are available and to help you choose one which is right for you.
The right base layer for you will depend to a large extent on the type of conditions to intend to use it in. As outlined above, a light summer base layer will have very different properties to an insulated winter one, and base layers designed for transition seasons (spring and autumn) will meanwhile aim to strike a balance between moisture management and insulation to keep you comfortable in changeable conditions. Ideally you will have a selection of base layers in your wardrobe to choose from as conditions demand; from lightweight summer specials to thick winter woollies, and something in between for those days that can’t quite make up their own mind.
Before you look at the different base layers on the market, it’s worth knowing a little about the different types and features.
• Materials: Base layers are made of a variety of materials and fabrics, both natural and man-made (synthetic). Merino wool is the most commonly-used natural fibre, with nylon, polyester, polypropelene and Lycra being common synthetic alternatives. Many base layers may utilize a blend of synthetic materials to achieve the desired balance of properties, or indeed a mixture of Merino and man-made fibres.
• Sleeves: Base layers are available in sleeveless, short-sleeve and long-sleeve versions. For the most part, sleeveless base layers are summer-only garments primarily worn for their wicking properties, short-sleeve base layers are ideal for cooler conditions in spring and autumn, and long-sleeve base layers help provide maximum insulation in the winter or on the ski slopes.
• Fit: Base layers should be snug and close-fitting in order to work properly, but not so restrictive as to impede movement. The inherent stretch in most base layer fabrics will help with this, although some base layers use contour mapping, where the weave of the fabric differs in certain areas, e.g. allows for more stretch over the shoulders. For cycle-specific base layers you may want to look for a cut the reflects the ergonomics of the on-bike position. Because a cyclist’s body shape changes when he or she is in a riding position, crouched over the handlebars, the design of bike wear reflects this. This position will pull up the rear and sleeves of the garment so arms are longer to ensure full coverage and some base layers will feature a long tail at the rear to prevent it riding up and exposing your back – also useful for protecting against wheel spray.
• Features: As above, all base layers should work to wick moisture away from the body and to trap an insulating layer of warm air when it’s cold. However some additional features are useful to watch out for – many synthetic base layers, for example, feature a microbial treatment on the fabric to combat the buildup of bacteria (from perspiration) and to help prevent odour. Others may have features such as flatlock seams which help prevent chafing and irritation.
Synthetic or natural fibre?
For many people choosing base layers the most common question is whether to go for a natural fibre – typically Merino wool – or a synthetic fibre such as polyester or polypropelene.
Merino: The Merino is an ancient breed of sheep adapted to life in colder climbs, and wool from this animal has excellent wicking and insulation properties as well as natural resistance to odour. The individual fibres are smoother and finer than normal coarse wool, making them soft and comfortable next to the skin and resulting in a stretchy fabric that is quick to adapt to the contours of your body yet returns easily to its original shape. The smooth fibres also offer less places for bacteria to hide and grow, meaning Merino wool stays smelling fresher, for longer. Merino additionally absorbs moisture and odour rather than wicking it to the surface like a synthetic fabric, making it the preferred choice of athletes who intend to spend long hours on the bike, track or slopes. The downsides of Merino, however,is that it can be relatively expensive and does require care when washing and drying. Additionally, the natural fibre may cause irritation in those with sensitive skin.
Synthethic fabrics: Synthetic base layers are usually made up of polypropylene, polyester, nylon or a blend of one or more of these. They are light, durable and have excellent wicking properties and moisture management abilities. Some synthetics such as polypropylene may use hollow fibres which are very effective both at wicking and at trapping air next to the skin – an essential feature for thermal base layers intended for winter use. Synthetic fabrics are easier to manipulate and therefore generally less expensive than Merino, and also don’t require as much specialised care when washing. However they may not be quite as comfortable next to the skin as natural Merino and without wool’s natural antibacterial properties can be prone to becoming smellier, faster. Some manufacturers use microbial treatments to combat this but in general, synthetic fabrics are more pungent than Merino.
Taking care of base layers
It’s essential to follow the manufacturer’s care instructions when washing and drying base layers, as natural fibres like Merino can shrink or be damaged with harsh soaps and hot wash cycles, while synthetic garments with microbial treatments may need similar care in order not to wash out the treatments from the fabric.
For Merino wool and treated synthetics a delicate soap, low spin setting and low temperature wash is advisable, and air drying rather than tumble drying. However individual garments may have their own requirements so check the label before bunging them in the wash!
Summer base layers
Short-sleeved or sleeveless summer base layers are designed to wick moisture away from the skin in hot conditions. They are made of thin fabric or even mesh with little insulating properties.
Spring/autumn base layers
Short-sleeved ‘transition’ base layers strike a balance between wicking and insulation for the changeable conditions of spring and autumn.
Winter base layers
Long-sleeved winter base layers have thermal properties and keep you warm by trapping a layer of air next to your skin. Base layers for extreme conditions may feature hollow-fibre construction for additional insulation and touches such as high collars to reduce exposure to cold.