HighCycle Study: Effect of High Altitude on Acute Mountain Sickness in Women Related to Their Menstrual Cycle Phase

HighCycle Study: Effect of High Altitude on Acute Mountain Sickness in Women Related to Their Menstrual Cycle Phase: A Prospective Cohort Study at 3600 m

Status

Completed

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT06499714

Enrollment

Registered

2024-07-12

Start date

2024-07-15

Completion date

2025-08-31

Last updated

2026-06-05

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Acute Mountain Sickness

Keywords

Women, Hypoxia, Prevention, Acetazolamide, Altitude

Brief summary

Prospective cohort study investigating the menstrual cycle phase (MCP)-dependent incidence of acute mountain sickness (AMS) in women travelling to 3600 m.

Interventions

OTHERExposure to 3600 m

Participants will travel to and stay for 2 days at an altitude of 3600 m.

Study design

Observational model

COHORT

Time perspective

PROSPECTIVE

Eligibility

Sex/Gender

FEMALE

Age

18 Years to 44 Years

Healthy volunteers

Yes

Inclusion criteria

* Healthy, non-smoking women, age 18-44 years, without any disease 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

Design outcomes

Primary

Measure	Time frame	Description
Acute Mountain Sickness (AMS) Incidence, LLS 2018	Day 1 to 3 at 3600 m	MCP-related difference in the AMS incidence. AMS incidence will be defined as a Lake Louise Questionnaire version 2018 score of ≥3.

Secondary

Measure	Time frame	Description
Acute Mountain Sickness (AMS) Incidence, LLS 1993	Day 1 to 3 at 3600 m	MCP-related difference in the AMS incidence. AMS incidence will be defined as a Lake Louise Questionnaire version 1993 score of ≥3.
Acute Mountain Sickness (AMS) Severity, LLS 2018	Day 1 to 3 at 3600 m	MCP-related difference on the AMS severity assessed by the Lake Louise Questionnaire version 2018.
Acute Mountain Sickness (AMS) Severity, LLS 1993	Day 1 to 3 at 3600 m	MCP-related difference on the AMS severity assessed by the Lake Louise Questionnaire version 1993.
Arterial blood gases	Day 2 at 760 m and day 2 at 3600 m	MCP-related difference on the arterial blood gases (pH, PaO2, PaCO2, SaO2).
Hypoxic ventilatory response	Day 2 at 760 m	MCP-related difference in the hypoxic ventilatory response assessed under FiO2 of 0.115 and while cycling on a bicycle at 30% of predicted maximal work capacity.
Perceived pain visualization	Day 1 to 3 at 3600 m	MCP-related difference on perceived pain sensations, visualized by the SMaRT tablet app

Countries

Kyrgyzstan

Contacts

STUDY_CHAIRMichael Furian, Prof. Dr.

University of Zurich

STUDY_DIRECTORTalant Sooronbaev, Prof. Dr.

National Center of Cardiology and Internal Medicine, Bishkek, Kyrgyzstan

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Jun 6, 2026