When the temperature climbs and your workout heats up, one thing becomes crystal clear: your underwear choice matters. While technical running shoes and moisture-wicking outerwear tend to take the spotlight, it’s often what you wear underneath that makes or breaks your comfort level. If you’re running in hot weather and find yourself dealing with chafing, sweat build-up, or discomfort, your underwear is probably to blame — and switching to breathable, natural fibres like bamboo or cotton could be the change your body thanks you for. At British Boxers, we specialise in lightweight, breathable underwear made from bamboo jersey and pure cotton — ideal for both everyday wear and light exercise, including summer running, walking, or cross-training in warm weather. What Should You Look for in Running Underwear? Good underwear for running in hot weather needs to be breathable, moisture-wicking, supportive, and non-restrictive. The goal is to minimise friction, allow airflow, and prevent sweat from sitting against the skin — particularly in high-friction areas. Most technical performance underwear on the market today is made from synthetic fibres like nylon, polyester, or elastane-rich blends. These can perform well in terms of moisture-wicking, but they don’t always suit people with sensitive skin, and can trap heat and bacteria when worn for long periods — especially if you’re not showering immediately after your run. That’s where natural fibres like bamboo and cotton offer a cooler, more skin-friendly alternative. Why Bamboo Underwear Is Ideal for Hot Weather Running Bamboo fabric is one of the best-kept secrets in the underwear world — especially for runners and active people. Its natural moisture-wicking properties help draw sweat away from the skin, while its thermoregulating abilities work to keep your body temperature balanced, even in the heat. Bamboo is also incredibly soft, meaning you’re far less likely to experience irritation or chafing on long runs. It’s hypoallergenic, antibacterial, and resists odour better than synthetic blends — all of which make it a great choice for running in high heat, especially if you’re layering over compression shorts or gym leggings. At British Boxers, our bamboo boxers and women’s full briefs are cut with just the right amount of stretch, support, and softness to make them perfect for low- to mid-impact summer workouts or outdoor jogs. Is Cotton a Good Choice for Running in the Heat? Cotton often gets a bad rap for workouts — but that’s only because the wrong type of cotton can retain moisture. However, lightweight, breathable, premium cotton underwear (like ours at British Boxers) performs much better. Our woven and jersey cotton underwear is light, airy, and naturally breathable. It’s perfect for shorter runs, everyday movement, and situations where you're likely to sweat but want to stay cool and comfortable. While cotton may not be as fast-drying as bamboo, it’s still a great choice for those with skin sensitivities or anyone who prefers the crisp, classic feel of all-natural fabric next to their skin.