Advances in Rain Gear
Breathable waterproof fabrics have been around since the 1970s. These technologies, whether using polyurethanes or other substances, work in a similar way, repelling moisture on the outside, while actually attracting moisture (from sweat) on the inside. The inside moisture seeks to find equilibrium from the warm, humid interior to the cooler area outside, where it can evaporate.
Unfortunately, when your body is under greater exertion, you can create more sweat than the material can successfully remove. This causes moisture to build up inside the clothing and can lead to either overheating as your activity continues or chilling once you stop. Polyurethane films in particular are continually being advanced and reformulated to tackle this very challenge. Overall design can also help, with air vents or zippers that can be adjusted as your body temperature changes.
In the end, all materials perform better when there is a greater variation between the outside and inside temperatures. So, when you are choosing rain gear, you may also want to consider polyurethane’s additional benefits. Gear made with polyurethane is generally lighter and easier to pack into small spaces and also has greater stretch. This not only helps garments keep their shape, it also protects it against hard impacts with substances like rock or ice. That means your gear is less likely to tear.