Effects of menstrual cycle phases on sprint training adaptations in women

Influence of Menstrual Cycle Phase on Metabolic and Performance Adaptations to Sprint Interval Training

This study tests how different phases of the menstrual cycle affect how women respond to sprint training to see if timing their workouts can help improve their performance.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 24 (estimated)
• Ages: 18 Years to 35 Years
• Sex: Female
• Sponsor: University of Toronto (Academic / other)
• Locations: 1 site (Toronto, Ontario)
• Trial ID: NCT06744517 on ClinicalTrials.gov

What this trial studies

This study investigates how different phases of the menstrual cycle affect the body's response to sprint interval training in healthy women. Participants will be randomly assigned to train during either the follicular or luteal phase of their menstrual cycle over a two-week period. The training consists of multiple short, intense sprints, and various performance metrics will be measured before and after the intervention. Blood and urine samples will confirm menstrual cycle phases and assess hormonal changes. The goal is to enhance understanding of female-specific training adaptations.

Who should consider this trial

Good fit: Ideal candidates are healthy, eumenorrheic women who engage in regular physical activity and meet specific fitness and menstrual cycle criteria.

Not a fit: Patients with hormonal contraceptive use, polycystic ovarian syndrome, or significant metabolic or cardiovascular diseases may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to optimized training protocols for women based on their menstrual cycle, improving athletic performance and health outcomes.

How similar studies have performed: While there is limited research on this specific topic, studies on exercise adaptations in women have shown varying results, indicating that this approach may provide new insights.

Eligibility criteria

Inclusion Criteria:

* Participating in 150 min of moderate-vigorous physical activity/week
* VO2peak of 'good' or above based on American College of Sport Medicine (ACSM) normative values(greater than 35.0ml/kg/min)
* Body mass index (BMI) between 18-27 kg/m2
* Performing 2-4 structured exercise sessions/week.
* Weight stable (within ± 2kg for at least 6 months)
* Non-smoker
* Menstrual cycle length of 27-35 days
* Minimal menstrual cycle length variability (less than 3 days)
* Ovulating monthly evidenced by a positive urinary luteinizing hormone surge
* Blood progesterone concentration greater than 16 nmol/L.

Exclusion Criteria:

* Hormonal contraceptive use within the last 3 months
* Polycystic ovarian syndrome (PCOS) or endometriosis
* Failure to meet MC verification criteria.
* Diagnosed with cardiovascular or metabolic disease, hyper- or hypogonadism, and/or PCOS
* The use of medication for managing blood glucose or lipid metabolism
* Current use of oral contraceptives or use within the last 3 months
* Irregular menstrual cycles (\<27 days or \>35 days)
* Pregnant or post-partum in the last 12 months, lactating or breast feeding within 3 months of the start of study, or menopausal
* Recreational smoking tobacco
* Inability to perform the study exercise protocols or follow the pre-trial dietary or physical activity controls
* Taking medications affecting substrate metabolism (corticosteroids or nSAIDs)
* Actively engaging in a low-carbohydrate diet (e.g., ketogenic, Atkins)

Where this trial is running

Toronto, Ontario

• Goldring Centre for High Performance Sport — Toronto, Ontario, Canada (Recruiting)

Study contacts

• Study coordinator: Jenna Gillen Assistant Professor, PhD

Conditions Healthy; exercise; women