It’s very rare to be “allergic” to chlorine in the usual sense, but after repeated exposures, many people experience an “irritant reaction” which looks and feels like an allergic reaction with swelling, itching and
sneezing, sniffling, and red eyes. Sometimes a scratchy throat and coughing are caused by free chlorine
particles in the air, especially in poorly ventilated indoor pools

When your eyes are exposed to chemically treated and/or hypotonic water (containing less salt than the cornea), the cornea may swell up. This edema causes the light rays to bend as they pass through,
which results in the halos around lights that sometimes plague swimmers. The eyes may also turn red, tear, and become overly sensitive to light and cigarette smoke. A nap, rinsing the eyes, and time, will
alleviate this condition; goggles will prevent it.

Although swimming wasn’t part of the ancient Olympics, it was enjoyed by the Greeks and other early civilizations. Young men swam in ancient Greece and Rome as part of their military training. The first
recorded swimming competitions were held in Japan in 36 B.C. Modern competitive swimming began in the mid-nineteenth century. Shortly thereafter, what later came to be known as the Amateur Swimming Association was formed and established rules for competition. In 1908, FINA (Fédération Internationale de Natation Amateur), the world governing body for swimming and other aquatic competition, was founded. When the first modern Olympiad was held in Greece in 1896, there were three men’s freestyle events, which were swum in the ocean. It wasn’t until the games held in Stockholm in 1912 that swimming events for women were included. Now, swimming is a major part of the summer games.