When looking for running pants, consider trousers with some synthetic material since 100% cotton pants trap moisture and keep sweat near to your body. You are more likely to feel chilly and unpleasant if your skin remains wet in freezing conditions; you are also more likely to get hypothermia. Therefore, choose running pants that are made of polyester or nylon fabric instead of cotton. Cotton is the most common material used in clothing because it's breathable, comfortable to wear and affordable. However, cotton absorbs water which can lead to pant legs being soaked through when running in heavy rain, making you feel cold and uncomfortable. This is why many runners prefer pants made from polyester or nylon materials instead. These fabrics are able to "breathe" so you don't overheat while running in hot climates or during exercise sessions that last long enough to become hot and sweaty. There are two types of running pants: those that fit at the waist and lower leg and have elasticized panels, and those that fit at the waist but not below it. The first type are easier to put on and take off than the second, as they do not need to be pulled up all the way or down all the way before being tied. They also tend to be less expensive than the second type of running pants. The best running pants have a lot of ventilation because sweat tends to evaporate if it isn't allowed to escape.