Abstract
Background: Menstrual period is a critical time in the life of females. It influences different daily life aspects; the pain during menstruation is one of the most common complaints in reproductive health and significantly affects the quality of life of the women. Most girls and women have primary dysmenorrhea of varying intensity at some point during their cycle. In some women, the pain is so severe to carry out their usual daily activities, like going to work or school, on 1 to 3 days every month. Exercise is one of the ways to reduce the severity of this pain. The purpose of this study was to observe the effect of aerobic exercises on primary dysmenorrhea among women.
Methodology: This is community based cross sectional study, conducted at Hail city, where 302 women were participated in this study. Data were collected by using a self-administered questionnaire which cover different variables, such as: socio-demographic characteristics and other variables related to study objectives.
Results: This study indicated that, the age of participants ranged from 21 to 29 years old within the mean of 25 years and SD of 4 years, while the number of aerobic exercises per week ranged from 2 to 4 days per week within mean of 3 days and SD of 1 day, while the degree of menstrual cycle pain severity ranged 2 to 6 points out of ten within the mean of 4 points and SD of 2 points. It also found that the prevalence of dysmenorrhea was 86% among participants and only 46% of participants consider aerobic exercises as a tool to reduce pain during primary dysmenorrhea. Finally, the study showed that there was statistically significant difference between regular aerobic exercises, average of aerobic exercises per week and primary dysmenorrhea.
Conclusion: The occurrence of pain during menstrual cycle is very high, and the use of regular aerobic exercises with moderate intensity can reduce or prevent the occurrence of primary dysmenorrhea.

Key words: Aerobic exercises, menstrual cycle, primary dysmenorrhea, Hail city, Saudi Arabia