HighCycle Study: Effect of High Altitude on Sleep Disordered Breathing in Women Related to Their Menstrual Cycle Phase

Recruiting

• Conditions: Sleep-Disordered Breathing
• Interventions: Other: Exposure to 3600 m

• Registration Number: NCT06498544
• Lead Sponsor: University of Zurich

Brief Summary

Prospective cohort study investigating the menstrual cycle phase (MCP) dependent sleep disordered breathing (SDB) in women travelling to 3600 m.

Detailed Description

Not available

Study Timeline

• Status Verified: 2024-07
• Study First Submitted: 2024-07-05
• Study First Submitted QC: 2024-07-05
• Last Update Submitted: 2024-07-05
• Study First Posted: 2024-07-12
• Last Update Posted: 2024-07-12
• Study Start: 2024-07-15
• Primary Completion: 2025-12-31
• Study Completion: 2025-12-31

Recruitment & Eligibility

• Status: RECRUITING
• Sex: Female
• Target Recruitment: 90

Inclusion Criteria

• Healthy, non-smoking women, age 18-44 years, without any diseases and need of regular medication (including oral contraceptives).
• BMI >18 kg/m2 and <30 kg/m2
• Born, raised and currently living at altitudes <1000 m
• Written informed consent
• Premenopausal, eumenorrheic cycle

Exclusion Criteria

• Other types of contraceptives (hormonal intrauterine device, vaginal ring, subcutaneous injections or implants, among others)
• Pregnancy or nursing
• Anaemic (haemoglobin concentration <10g/dl)
• Any altitude trip <4 weks before the study
• Allergy to acetazolamide and other sulfonamides

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Women in luteal MCP	Exposure to 3600 m	Women being in their luteal MCP on the day of ascent to high altitude.
Women in follicular MCP	Exposure to 3600 m	Women being in their follicular MCP on the day of ascent to high altitude.

Primary Outcome Measures

Name	Time	Method
Nocturnal oxygen saturation (SpO2)	Night 1 at 760 m and Night 1 at 3600 m	MCP-related difference in altitude-induced change in the mean nocturnal oxygen saturation measured by pulse oximetry.

Secondary Outcome Measures

Name	Time	Method
Nocturnal oxygen desaturation index (ODI)	Night 1 at 760 m and Night 2 at 3600 m	MCP-related difference in altitude-induced change in the ODI (number of ∆SpO2 \>3% per hour time in bed measured by pulse oximetry).
Nocturnal oxygen saturation (SpO2)	Night 1 at 760 m and Night 2 at 3600 m	MCP-related difference in altitude-induced change in the mean nocturnal oxygen saturation measured by pulse oximetry.
Apnea/hypopnea index (AHI)	Night 1 at 760 m and Night 2 at 3600 m	MCP-related difference in altitude-induced change in the mean number of apneas/hypopneas per hour.
Subjective sleep quality	Night 1 at 760 m and Night 2 at 3600 m	MCP-related difference in altitude-induced change in subjective sleep quality assessed by a 100-mm visual analog scale.

Trial Locations

Locations (1)

National Center for Cardiology and Internal Medicine; 🇰🇬 Bishkek, Kyrgyzstan