Cramping begins just before or at the onset of the menstrual flow. Other symptoms include nausea, vomiting, and frequent bowel movements with cramps. Dizziness, fainting, and paleness may also occur. About 10 percent of women have severe dysmenorrhea. These women may have partial or total disability during their periods.
Menstrual pain is caused by the release of a hormone called prostaglandin.
The hormone is responsible for the normal functions of the uterus during menstruation. Other muscles in the body release this same hormone when injured. Exercise does not increase a woman's risk for severe dysmenorrhea. In fact, exercise can reduce the discomforts caused by a woman's monthly period. Female athletes report less than normal pain with their periods.