A bra should not be worn for swimming because it is made of different material that can be damaged by the chlorine in pool water. The bra will no longer be as elastic. If you do wear one while swimming then afterward it should be washed in anti-chlorine shampoo. It should also not be worn while swimming at the beach. First of all bras are not made to me waterproof and second bras can soak up water and become too heavy. Wear bikinis and bathing suits instead that are meant for swimming.