Effect of Short-term Descent to Low Altitude in Healthy Residents at Moderate Altitude (>1000 m.a.s.l.).

February 15, 2026 updated by: Tsogyal Latshang

The Different Diagnostic Values of Polysomnographies at Low and at Moderate Altitude - A Randomized Crossover Trial

The purpose of this study is to investigate the effect of short-term descent in healthy residents at moderate altitude (>1000 m.a.s.l.).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Polysomnographies will be done for each participant for 2 consecutive nights at the sleep laboratory in Chur (CH; 590 m.a.s.l.) as well as for 2 consecutive nights at the participants home elevations (CH; >1000 m.a.s.l.). Between the measurements at those two different altitudes there will be a two-week washout period at >1000 m.a.s.l.. The sequence of altitude exposure will be randomized.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
44

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • Switzerland
      • Chur, Switzerland
        • Kantonsspital Graubunden

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Healthy (no current medical condition or intake of regular medication, except negligible medical issues or accidents not interfering with the current health status or physical performance.)
  • Living above 1000 m.a.s.l. since at least 1 year
  • No overnight stay at altitudes <1000 m.a.s.l. in the previous 4 weeks
  • 18-70 years old
  • Body mass index 18,5-30 kg/m2
  • informed consent

Exclusion Criteria:

  • Active diseases or health related conditions that require treatment (sleep disorders (mainly sleep apnea), chronic rhinitis, cardiovascular and lung diseases)
  • Use of drugs that affect the respiratory center drive (sedatives, sleep inducing drugs, opioids), stimulants or illegal drugs
  • Regular consumption of recreational drugs (alcohol and nicotine included)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: A
Polysomnographies will be done first for 2 nights at the sleep laboratory in Chur (590 m.a.s.l.) and after a two-week washout period for 2 nights at the participants home elevations (>1000 m.a.s.l.).
Diagnostic test: Descent to low altitude
The polysomnographic recordings include electroencephalogram (EEG), electrooculogram (EOG), electromyogram (EMG), electrocardiogram (ECG), pulse oximetry, transcutaneous capnography, nasal airflow and thoracic and abdominal respiratory effort.
Experimental: B
Polysomnographies will be done first for 2 nights at the participants home elevations (>1000 m.a.s.l.). and after a two-week washout period for 2 nights at sleep laboratory in Chur (590 m.a.s.l.).
Diagnostic test: Descent to low altitude
The polysomnographic recordings include electroencephalogram (EEG), electrooculogram (EOG), electromyogram (EMG), electrocardiogram (ECG), pulse oximetry, transcutaneous capnography, nasal airflow and thoracic and abdominal respiratory effort.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
T90 (time spent in SpO2 below 90%)
Time Frame: 4 nights
T90 is the percent of sleeping time which the participant spent in SpO2 below 90%. It provides information about the duration and degree of hypoxia during the whole sleep.
4 nights

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
AHI (apnea-hypopnea index)
Time Frame: 4 nights
AHI is defined as the number of apneas and hypopneas per hour of sleep, whereby apnea is defined as a cessation of the airflow for ≥10 seconds, while hypopnea is defined as a reduction of the airflow ≥30% with an oxygen desaturation ≥3% or an arousal.
4 nights
SWS (slow-wave sleep)
Time Frame: 4 nights
SWS includes the deep sleep phase. Deep sleep is amongst other important for energy restoration, immune system strengthening and regeneration of cells.
4 nights
AI (arousal index)
Time Frame: 4 nights
AI is the number of arousals per hour of sleep, whereby an arousal is an interruption of sleep from 3-15 seconds. They prevent suffocation in the sleep apnea by interrupting breathing pauses but are also coupled with a lot of stress for the human body.
4 nights
SpO2 (oxygen saturation)
Time Frame: 4 nights
SpO2 is the amount of haemoglobin bound to oxygen. Normal values lie above 95%. Values below 90% are considered as low and require treatment.
4 nights
TcCO2 (partial pressure of carbon dioxide)
Time Frame: 4 nights
TcCO2 correlates with PaCO2 and is therefore a non-invasive alternative. A normal value of PCO2 lies between 35 and 45 mmHg. Lower values can lead to muscle cramps, abnormal heartbeat and much more.
4 nights
WASO (wakefulness after sleep onset)
Time Frame: 4 nights
WASO is the time spent awake after sleep onset. High values of WASO are for example found in sleep apnea, insomnia and restless leg syndrome.
4 nights
ODI (oxygen desaturation index)
Time Frame: 4 nights
ODI is defined as the number of oxygen decreases ≥3% per hour of sleep.
4 nights

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Tsogyal Latshang

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Tsogyal Latshang, PD Dr. med., Kantonsspital Graubunden

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 30, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 16, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 16, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 15, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 12, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 24, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 18, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 15, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2025

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2023-00636

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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