During exercise, sweat gets drawn away from your skin and onto the fibers of your T-shirt. If your tee is made from a natural fabric like cotton, the moisture gets absorbed into the fibers. This makes the T-shirt feel wet and heavy. Consider Your Activity: If you are just going to the gym, or if your outdoor excursion will not take long, you might be able to get away with choosing comfort and style over performance. During exercise, sweat gets drawn away from your skin and onto the fibres of your T-shirt. If your tee is made from a natural fabric like cotton, the moisture is absorbed into the fibres. This makes the T-shirt feel damp and heavy. Burning, Bleaching, Ironing, Exposure To Liquids, Tumble Drying, Clothing Tears, Washing Incorrectly.