Investigating the Effects of Time-of-day and Menstrual Cycle Phase (Low and High Progesterone) on… (NCT07399847) | Clinical Trial Compass
Not Yet RecruitingNot Applicable
Investigating the Effects of Time-of-day and Menstrual Cycle Phase (Low and High Progesterone) on Female's Cognitive and Strength Performance
30 participantsStarted 2026-02
Plain-language summary
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.
Who can participate
Age range
18 Years – 30 Years
Sex
FEMALE
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria:
* Female (assigned at birth)
* Aged 18-30 years
* Tier 2 athlete which requires the participants to identify with a specific sport, train with a purpose to compete, regularly train \~3 times per week and compete at a local level (for example being a member of a BUCS sport and competing regularly with that sport)
* Regular menstrual cycle - considered between 21-35-day cycles with at least 9 periods a year.
Exclusion Criteria:
* The current/previous (in the last 3 months) use of any contraceptive method that alter the menstrual cycle
* The use of the emergency contraceptive pill either 3 months prior to the study or during the study
* Diagnosis of menstrual disorders including (but not exclusively) endometriosis and Polycystic Ovary Syndrome (PCOS)
* A formal diagnosis of sleep disorders such as insomnia
* Consume \>400mg/day of caffeine
* A musculoskeletal injury in the past 3 months
* A formal diagnosis of neurological or psychiatric disorders such as Attention-Deficit/Hyperactivity Disorder (ADHD), Autism Spectrum Disorder (ASD), Dyslexia or schizophrenia
* Taking prescribed medication that may affect sleep for example stimulants such as Methylphenidate
* No regular night shift work
* No trans-meridian travel within 10 days of their expected participation dates (travel that will cause jetlag)
* Have given blood in the last 12 weeks - this is not strictly an exclusion; participants will just need to wait until after 12 weeks before taking part in the s…
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Change in muscle strength with time-of-day and menstrual cycle phase
Timeframe: 07:00, 12:00 and 18:00 hours in phase 1 and 4 (the points of low and high progesterone) of the menstrual cycle (each cycle is 21-35 days). Phase 1 is during menstruation and phase 4 is +7 days (±1) after the confirmation of the luteinising hormone peak.