Swimming is great exercise, but chlorine is an asthma trigger for some people. In others, chlorine triggers itchy, red eyes or a rash. If you don't feel well after a water workout, it could be that your pool is not properly ventilated, or the maintenance crew could be using too much chlorine. Ask them to check the levels, but if you still feel awful after swimming laps, it might be time to consider a saltwater pool, which disinfects water without the use of chlorine. Some gyms have started to move away from chlorine, but the only way to know that is to call around to the pools in your area. To cut down on additional chlorine exposure and to cut down on chloroform levels circulated around your house, shower immediately in properly filtered water after swimming.