Amenorrhea and oligomenorrhea risk related to exercise training volume and intensity: Findings from 3705 participants recruited via the STRAVA™ exercise application

\Objectives: To investigate associations between self-reported exercise training habits and amenorrhea/oligomenorrhea among physically active women. Design: A cross-sectional survey was completed by 3705 women (median age = 40 years [quartile 1, quartile 3: 30, 45], body mass index = 22.1 kg/m(2) [20.5, 24.2]) representing multiple nationalities and sports via the STRAVA (TM) exercise application. Respondents selected the amount of time they participated in low intensity, moderate intensity, and high intensity exercise training per week. Amenorrhea/oligomenorrhea was defined as self-reporting <= 10 menses in the last year. Methods: Associations between weekly exercise volumefor low intensity training, moderate intensity training, and high intensity training and amenorrhea/oligomenorrhea were modeled with univariate logistic regression models, followed by adjustment for age and body mass index. Results: Amenorrhea/oligomenorrhea prevalence was 16 % (n= 576/3705), with no difference by country of origin or most sport modes. In adjusted models, participating in low intensity training >= 7 h/week or moderate intensity training >= 6 h/week was associated with 1.43 (95 % confidence interval: 1.04-1.96) and 1.46 (1.10-1.95) greater odds of amenorrhea/oligomenorrhea compared to 2 to 3 h/week, respectively. Similarly, high intensity training >= 5 h/week was associated with 1.41 (1.03-1.92) greater odds of amenorrhea/oligomenorrhea compared to 1 to 2 h/week. Participating in low intensity training for >= 30 min/week compared to 2 to 3 h/week was associated with reduced amenorrhea/oligomenorrhea odds (0.65 [0.44-0.94]). Conclusions: Taken together, these associations suggest greater weekly exercise volume, irrespective of intensity, may increase amenorrhea/oligomenorrhea risk among physically active women. (c) 2023 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.