Base layers
Base layers are worn directly against the skin, with a snug (but not restrictive) fit. Their role is to regulate body temperature and wick moisture away from your skin. Too often hillwalkers neglect the humble base layer in favour of splashing the cash on jazzy insulated jackets and waterproofs, but this is a flawed approach – if your cotton t-shirt is damp with sweat and failing to dry quickly, you’ll end up cold and uncomfortable even if you are wearing a £400, top-of-the-range down jacket. Instead you should always wear a lightweight, technical and fast-wicking base layer as your foundation layer. But merino wool or synthetic polyester? That is your biggest decision in terms of fabrics. Merino wool base layers are warmer than synthetic ones. They are also odour-resistant, fast-wicking
and more comfortable when wet, but generally more expensive. Synthetic base layers are better value, with faster wicking and drying, but inferior warmth. A popular strategy is to opt for merino wool base layers in colder climes and synthetic layers for milder conditions or during higher-intensity activities.
Base layers are often season-specific too. Heavier, thicker and higher grades of merino wool (measured in gsm – grams per square metre) will provide more insulation for winter, while some ultra-light synthetic base layers are designed to keep you cool and dry in summer. Hybrid base layers blend merino wool and synthetic fibres into one product with the aim of retaining the best properties of both.
Perhaps the most commonly used base layers are short-sleeve t-shirts for hiking, and long-sleeved thermal tops and long johns for camping, but don’t forget about technical underwear. Technical products, such as merino boxers, bras and pants, will perform far better than your everyday pairs.