Compression Garments

Compression garments are pieces of clothing, such as socks, pantyhose, sleeves, etc., that provide support that is especially useful for people who have to stand for long periods, or people with poor circulation. The garments can come in varying degrees of compression. The higher degrees require a doctor's prescription.  Compression garments worn on the legs can help prevent deep vein thrombosis and reduce swelling, especially while traveling.

Compression sportswear is also worn by some athletes during exercise to prevent chafing and rashes, and post-exercise to ease muscle stiffness and quicken recovery time.

source: https://en.wikipedia.org/wiki/Compression_garment