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

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.

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 study