Author(s): ABBOTT, S., HARDWICKE, J., HOUGH, J., JOHNSON, M.A., WILLIAMS, N.C., Institution: NOTTINGHAM TRENT UNIVERSITY, Country: UNITED KINGDOM, Abstract-ID: 918

INTRODUCTION:
Many female athletes perceive that their menstrual cycle (MC) impacts their ability to train and perform optimally. However, the specific effect of the MC on gastrointestinal (GI) symptoms in physically active or athletic populations has not been thoroughly explored. Furthermore, it remains unclear how potential MC-related GI symptoms may impact an athlete's planned exercise activity and nutritional behaviours pre-, during, and post-exercise. Therefore, this study sought to investigate the effect of the MC on GI symptoms and the subsequent impact on exercise and nutritional behaviours.
METHODS:
A mixed-methods observational study design was utilised, with twenty-nine physically active females completing daily questionnaires, including quantitative and qualitative measures, throughout one full MC. Data gathered from the daily questionnaire included GI symptoms and the impact of those GI symptoms on planned exercise activity and nutritional behaviours throughout the day. The MC was classified into five pre-defined phases: phase 1 (P1; indicated by the onset of bleeding until day 5), phase 2 (P2; 72 – 24 hours prior to a positive ovulation test), phase 3 (P3; the day of, and the day after, a positive ovulation test), phase 4 (P4; 6 – 8 days following a positive ovulation test), and a pre-menstrual stage (Pre-M; the final 3 days of the MC).
RESULTS:
The average total, upper and lower GI symptom scores were 82 – 208% greater in P1, compared to all other menstrual phases (p < 0.01). Within P1, daily total GI symptom score was greater on day 1 than day 3 (p = 0.002), day 4 (p = 0.005) and day 5 (p < 0.001) and was also elevated on day 2, compared to day 4 (p = 0.008) and day 5 (p = 0.005). Across all phases, the most frequently reported GI symptoms were bloating, flatulence, lower abdominal bloating and urge to defecate. Eight participants (28%) reported a perceived reduction in exercise performance due to GI symptoms experienced around exercise. During P1, fourteen participants (48%) reported that their GI symptoms impacted their planned exercise activity, including missing or adapting training by reducing the duration and/or intensity of exercise. In P1, ten participants (34%) stated that GI symptoms impacted their pre-exercise nutritional behaviours, reducing the quantity of food/drink consumed and/or avoiding eating close to the start of exercise.
CONCLUSION:
This study identified clear differences in GI symptom incidence and severity across the MC. Total, upper and lower GI symptoms scores were greatest during P1 and were found to be most elevated on days 1 and 2. These findings highlight the need for future research to develop targeted strategies to mitigate GI symptoms in physically active females, particularly during P1, to reduce disruptions to training and exercise-related nutritional practices and optimise athlete wellbeing and performance.