Investigating the Effects of Time-of-day and Menstrual Cycle Phase (Low and High Progesterone) on Female's Cognitive and Strength Performance

This study is designed to determine whether time-of-day and menstrual cycle phase influence athletic performance and is expected to contribute valuable insight into how both time-of-day, and hormonal factors can influence performance and expand existing research. This study aims to support more inclusive, effective and personalised approaches to training and competition schedules for female athletes. The study will involve two testing days that require a participant to complete a compilation of tests at 07:00, 12:00 and 18:00 hours. The testing days will be arranged for when a participant is in phase 1 (lowest levels of progesterone in the menstrual cycle) and phase 4 (highest level of progesterone in the menstrual cycle). The tests will examine a participant's executive function and physical strength. This study will aim to recruit thirty 18-30-year-old females from Lancaster University who identify with a sport that they train \~3 times a week for with a purpose to compete. The females recruited must have a regular menstrual cycle and no history of sleep disorders. Aim: To investigate the effects of time-of-day and menstrual cycle phase (low and high progesterone levels) on executive function and strength in females. Objectives: 1. To determine the effects of time-of-day on executive function and strength tests. 2. To determine the effects of menstrual cycle phase on executive function and strength tests. 3. To examine if there is an interaction between time-of-day and menstrual cycle phase on executive function and strength tests.

NCT Number	NCT07399847
Lead Sponsor	Lancaster University Collaborators: Liverpool John Moores University
Conditions	Circadian Rhythm, Menstrual Cycle Phase, Female Athletes, Executive Function (Cognition), Eumenorrhea, Strength
Enrollment	30 participants
Start Date	2026-02
Primary Completion	2026-06 (estimated)
Study Completion	2026-09 (estimated)
Updated on ClinicalTrials.gov	2026-02-10