Black Pyramid Track Pants Sweatpants are usually made from cotton or polyester, often of a heavy knit. They often have elastic in the waist, and may or may not have pockets. Sweatpants are traditionally ash gray in color but are now available in most colors. They are usually quite "baggy" and loose, making them easy to put on and take off; moreover they have flexibility and comfort. In addition, this design traps less heat than most conventional, lightweight trousers, which may be a disadvantage in some conditions such as cold temperatures and an advantage in others such as body heat-increasing aerobic activities. Warmer varieties can be made from polar fleece. Once these practical pants were only worn for sporting events and at home. Now, they are available in many fashionable styles and are worn in a variety of public situations. Because of their comfort and fashion, they have become a popular choice of clothing. The sweatpant variations described below are made from many different materials and in many forms.