Primary dysmenorrhea and physical activity. Med. Sci. Sports Exerc., Vol. 30, No. 6, pp. 906-909, 1998. It has been widely claimed that exercise is beneficial to dysmenorrhea, yet solid evidence is lacking. Studies investigating this relationship have been reviewed for this paper. Most showed decreased prevalence and/or improved symptomatology with exercise. However, controlled longitudinal studies involving women with confirmed primary dysmenorrhea who are sufficiently blinded to the study objectives are necessary before a definite relationship between exercise and dysmenorrhea can be established.