Winter swimming in South Boston began in the 19th century, by some accounts as early as 1865. The practice was likely introduced by European immigrants, who believed that cold water plunges followed by saunas or steam baths were good for one's health. Swimmers who came regularly to the L Street Bathhouse in South Boston usually swam nude or with minimal clothing, and became known as the "Brownies" because of the deep tans they acquired from daily exposure to the sun. The Brownies claimed that swimming and tanning were beneficial to the heart, skin, and circulation, and credited the practice with miraculous cures. The belief that winter swimming strengthens the immune system has persisted into the 21st century.
