Lessons learned about research on premenstrual syndrome.

We discuss specific problems in implementing research to evaluate exercise treatment for premenstrual syndrome (PMS). Modifications of lifestyle, such as implementing exercise regimens, frequently are recommended as treatment for PMS, but evidence supporting this treatment is largely anecdotal. Originally, we designed a study to examine the effects of physical exercise on the symptoms of PMS. Despite initial enthusiasm, the majority of participants dropped out before beginning the active intervention segment of the study. This unexpected attrition resulted in a review of methodology, including recruitment and study design, in an attempt to understand factors related to research on exercise-based treatments of PMS so future researchers would be cognizant of the obstacles inherent in such research. Such understanding will allow research to advance more efficiently by enabling investigators to avoid the pitfalls we identified.