Examining physical activity and menstrual cycle experiences among insufficiently active women: Project PACE protocol

Introduction Physical activity (PA) is known to mitigate risk for cardiovascular disease (CVD) and improve overall well-being, though many women do not meet national PA guidelines. Menstrual-related symptoms and related biopsychosocial fluctuations may be a key, but often overlooked, determinant of daily PA behavior. Traditional methods of assessment are limited in their ability to capture such dynamic experiences within-person. Methods Using a 45-day intensive assessment protocol, Project PACE is designed to overcome the limitations of existing approaches, to examine temporal associations between menstrual symptoms, PA, and related experiences (e.g. sleep) among insufficiently active women with at least one CVD risk marker. Participants (N = 60) will self-report menstrual symptoms, PA, PA-related cognitions, and other daily health behaviors twice per day via electronic surveys, and wear a Fitbit Inspire device for continuous assessment of PA and sleep. Primary analyses will use multilevel models to examine within-person associations between daily menstrual cycle symptoms and PA behavior, while exploratory analyses will examine potential mechanisms and sources of heterogeneity in these associations. Results We hypothesize that (1) PA behavior, menstrual experiences, and cognitive PA determinants (e.g. motivation, intentions, self-efficacy) will be highly variable within-person, reflecting low stability across days, and (2) on days when participants experience more intense symptoms relative to their typical levels, they will report lower motivation, intentions, and self-efficacy for PA. Discussion The goal of this study is to clarify these associations among women ages 18-50. This information will be useful for informing improvements to personalized and adaptive PA interventions for women.