Van Dyken had severe asthma throughout her childhood and into adulthood. She began swimming on the advice of a doctor as a way to strengthen her lungs to cope with her condition and prevent future asthma attacks.
She won six Olympic gold medals in her career, four of which she won at the 1996 Summer Olympics, making her the first American woman to accomplish such a feat and the most successful athlete at the 1996 Summer Olympics. She won gold in the 50-meter freestyle, 100-meter butterfly, 4×100-meter freestyle relay, and 4×100-meter medley relay.
