The effect of Exercise on the Age at Menarche in Girls at Guidance Schools of Shiraz, Iran

Menarche is a woman’s first menstruation and is determined by multiple factors. The aim of this study was to evaluate the effect of exercise on the age of menarche in girls at guidance schools of Shiraz, Iran. This cross-sectional study attempted to evaluate the effect of regular exercise on the age of menarche in relation to demographic data in 483 randomly selected girls from guidance school in Shiraz, Iran, using statistical analysis including independent t-test, variance analysis and linear regression tests. Participants were divided in two groups including 181 and 302 athletic and non-athletic girls, respectively. A statistically significant difference was found in the mean age at menarche between athletic 12.4 ± 0.9 SD and non-athletic girls 12.1 ± 1.0 SD years (P = 0.003). Linear regression indicated that mother’s age (P = 0.049) and exercise (P = 0.001) both have significant association with age at menarche. The age at menarche for the athletic group was significantly delayed. Exercise and mother’s age were significantly associated with age at menarche, whereas no significant association was observed between age at menarche and weight, BMI, father’s age, and mother’s and father’s educational levels.