The Effect of the Menstrual Cycle on Immune Cell Activity and Recovery After Resistance Exercise

Recruiting

• Conditions: Healthy Women; Menstruation; Resistance Exercise

• Registration Number: NCT06985420
• Lead Sponsor: University of Central Florida

Brief Summary

The goal of this observational study is to learn how the menstrual cycle affects immune cell activation, recruitment, and recovery responses after resistance exercise in healthy, resistance-trained women aged 18-40. The main questions it aims to answer are:

Does the menstrual cycle influence neutrophil recruitment and adhesion after resistance exercise? Does the menstrual cycle affect markers of muscle damage and functional recovery? Researchers will compare three menstrual phases (early follicular, late follicular, and mid-luteal) to see if immune responses and recovery outcomes differ across these phases.

Participants will:

Complete resistance exercise protocols across three different menstrual cycle phases.

Provide blood samples to assess immune cell activation and muscle damage markers.

Track sleep, mood, and recovery with questionnaires and wear an accelerometer.

Detailed Description

Not available

Study Timeline

• Study Start: 2024-08-16
• Study First Submitted: 2024-09-16
• Status Verified: 2025-05
• Primary Completion: 2025-05
• Study Completion: 2025-05
• Study First Submitted QC: 2025-05-14
• Last Update Submitted: 2025-05-14
• Study First Posted: 2025-05-22
• Last Update Posted: 2025-05-22

Recruitment & Eligibility

• Status: RECRUITING
• Sex: Female
• Target Recruitment: 40

Inclusion Criteria

• Women between the ages of 18 and 40.
• Must weigh at least 110 pounds.
• Healthy as determined by medical history, physical activity readiness, and menstrual cycle questionnaires.
• Actively resistance training for at least 6 months (minimum of 3 resistance training sessions per week, with at least one lower body session).
• Pre-menopausal and have a regular menstrual cycle (eumenorrheic), with a clear start of menses (early follicular phase).
• Not currently pregnant or planning to become pregnant during the study.
• Have not used hormonal birth control or intrauterine devices in the past 3 months (or three full menstrual cycles).
• Able to recall approximate start dates of their last 6 menstrual cycles.
• Willing to follow study instructions, including avoiding exercise, alcohol, and caffeine before testing visits.
• Free from previous or current lower body injuries that could limit performance.
• Not regularly taking any medications that could interfere with the study.
• Determined to have a high likelihood of successful blood draws by a certified phlebotomist.

Exclusion Criteria

• Do not give consent to participate.
• Have been determined unfit to participate based on medical or activity history (using health questionnaires).
• Currently take prescription or over-the-counter medication that could affect the study results.
• Have a chronic illness requiring medical care.
• Not currently resistance-trained (don't meet the exercise requirement).
• Pregnant or planning to become pregnant during the study.
• Do not have regular periods or have been diagnosed as amenorrhoeic (absence of menstruation).
• Currently taking any performance-enhancing drugs.
• Currently using hormonal birth control or intrauterine devices (IUDs), or have used them in the past three months (or three full menstrual cycles).
• Determined unlikely to have a successful blood draw by a trained phlebotomist.
• Weigh less than 110 pounds.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Neutrophil Recruitment and Adhesion Dynamics	From enrollment, through study completion, an average of 4 months.	Measure: Neutrophil cell index (impedance reflecting neutrophil migration) using Real-Time Cell Analysis (RTCA). Objective: To assess the differences in neutrophil recruitment and adhesion across menstrual cycle phases (early follicular, late follicular, and mid-luteal).; Time Frame: Assessed at 2 time points (baseline and 4 hours post exercise) on 3 experimental trial days (1 per menstrual cycle; up to 4 cycles per participant, over approximately 16 weeks).
Systemic Concentrations of CXCL8	From enrollment, through study completion, an average of 4 months.	Measure: Plasma levels of CXCL8 (interleukin-8). Objective: To evaluate if menstrual cycle phases influence systemic chemokine levels in response to exercise.; Time Frame: Collected at 2 time points (baseline and 4 hours post exercise) on 3 experimental trial days (1 per menstrual cycle; up to 4 cycles per participant, over approximately 16 weeks).
Muscle Function and Recovery- Active Range of Motion	From enrollment, through study completion, an average of 4 months.	Measure: Changes in active range of motion (AROM). Objective: To examine the impact of the menstrual cycle on functional recovery following resistance exercise.; Time Frame: Assessed at 5 time points (baseline, immediately post-exercise, 4 hours post, 24 hours post, and 48 hours post) on 3 experimental trial days (1 per menstrual cycle; up to 4 cycles per participant, over approximately 16 weeks).
Muscle Function and Recovery- Pain Pressure Threshold	From enrollment, through study completion, an average of 4 months.	Measure: Changes in pain pressure threshold (PPT). Objective: To examine the impact of the menstrual cycle on functional recovery following resistance exercise.; Time Frame: Assessed at 5 time points (baseline, immediately post-exercise, 4 hours post, 24 hours post, and 48 hours post) on 3 experimental trial days (1 per menstrual cycle; up to 4 cycles per participant, over approximately 16 weeks).
Muscle Function and Recovery - Countermovement Jump	From enrollment, through study completion, an average of 4 months.	Measure: Changes in countermovement jump (CMJ) height. Objective: To examine the impact of the menstrual cycle on functional recovery following resistance exercise.; Time Frame: Assessed at 5 time points (baseline, immediately post-exercise, 4 hours post, 24 hours post, and 48 hours post) on 3 experimental trial days (1 per menstrual cycle; up to 4 cycles per participant, over approximately 16 weeks).
Muscle Function and Recovery - Maximal Voluntary Isometric Contraction	From enrollment, through study completion, an average of 4 months.	Measure: Changes in maximal voluntary isometric contraction (MVIC). Objective: To examine the impact of the menstrual cycle on functional recovery following resistance exercise.; Time Frame: Assessed at 5 time points (baseline, immediately post-exercise, 4 hours post, 24 hours post, and 48 hours post) on 3 experimental trial days (1 per menstrual cycle; up to 4 cycles per participant, over approximately 16 weeks).

Secondary Outcome Measures

Name	Time	Method
Subjective Measures of Fatigue	From enrollment, through study completion, an average of 4 months.	Measure: Visual Analog Scale (VAS) ratings for fatigue. Objective: To assess perceived fatigue across menstrual cycle phases.; Time Frame: Assessed at 5 time points (baseline, immediately post-exercise, 4 hours post, 24 hours post, and 48 hours post) on 3 experimental trial days per participant (approximately 16 weeks total).
Mood	From enrollment, through study completion, an average of 4 months.	Measure: Profile of Mood States (POMS). Objective: To examine the influence of the menstrual cycle on mood during recovery from exercise.; Time Frame: Assessed at 5 time points (baseline, immediately post-exercise, 4 hours post, 24 hours post, and 48 hours post) on 3 experimental trial days per participant (approximately 16 weeks total).
Subjective Measures of Soreness	From enrollment, through study completion, an average of 4 months.	Measure: Visual Analog Scale (VAS) ratings for soreness. Objective: To assess perceived soreness across menstrual cycle phases.; Time Frame: Assessed at 5 time points (baseline, immediately post-exercise, 4 hours post, 24 hours post, and 48 hours post) on 3 experimental trial days per participant (approximately 16 weeks total).
Objective Sleep Quality	From enrollment, through study completion, an average of 4 months.	Measure: Actigraph Accelerometer data. Objective: To investigate whether menstrual cycle phases impact objective sleep quality.; Time Frame: Continuously monitored from 72 hours before to 48 hours after exercise on each of 3 experimental trial days (approximately 16 weeks total).
Systemic Concentrations of Creatine kinase	From enrollment, through study completion, an average of 4 months.	Measure: Plasma levels of creatine kinase (CK). Objective: To determine how menstrual cycle phases affect muscle damage/inflammation markers after resistance exercise.; Time Frame: Collected at 5 time points (baseline, immediately post-exercise, 4 hours post, 24 hours post, and 48 hours post) on 3 experimental trial days per participant (approximately 16 weeks total).
Systemic Concentrations of Myoglobin	From enrollment, through study completion, an average of 4 months.	Measure: Plasma levels of myoglobin (MYB). Objective: To determine how menstrual cycle phases affect muscle damage/inflammation markers after resistance exercise.; Time Frame: Collected at 5 time points (baseline, immediately post-exercise, 4 hours post, 24 hours post, and 48 hours post) on 3 experimental trial days per participant (approximately 16 weeks total).
Systemic Concentrations of C-Reactive Protein	From enrollment, through study completion, an average of 4 months.	Measure: Plasma levels of C-reactive protein (CRP). Objective: To determine how menstrual cycle phases affect muscle damage/inflammation markers after resistance exercise.; Time Frame: Collected at 5 time points (baseline, immediately post-exercise, 4 hours post, 24 hours post, and 48 hours post) on 3 experimental trial days per participant (approximately 16 weeks total).
Subjective Measures of Perceived Recovery	From enrollment, through study completion, an average of 4 months.	Measure: Visual Analog Scale (VAS) ratings for recovery. Objective: To assess perceived recovery across menstrual cycle phases.; Time Frame: Assessed at 5 time points (baseline, immediately post-exercise, 4 hours post, 24 hours post, and 48 hours post) on up to 4 experimental trial days per participant (approximately 16 weeks total).
Subjective Sleep Quality	From enrollment, through study completion, an average of 4 months.	Measure: Self-Assessment of Sleep Survey (SASS-Y). Objective: To investigate whether menstrual cycle phases impact subjective sleep quality.; Time Frame: Assessed at 1 time point (baseline) on 3 experimental trial days per participant (approximately 16 weeks total)
Menstrual Distress	From enrollment, through study completion, an average of 4 months.	Description: Measure: Menstrual Distress Questionnaire (MEDI-Q). Objective: To examine the influence of the menstrual cycle on menstrual distress reporting. Time Frame: Assessed at 1 time point (baseline) on 3 experimental trial days per participant (approximately 16 weeks total)

Trial Locations

Locations (1)

University of Central Florida; 🇺🇸 Orlando, Florida, United States