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

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: Completed
• Conditions: Healthy
• Intervention / Treatment: Diagnostic test: Descent to low altitude

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: Interventional
• Enrollment (Actual): 44
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Chur, Switzerland
    • Kantonsspital Graubünden

Participation Criteria

Eligibility Criteria

• 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

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
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

Outcome Measure	Measure Description	Time Frame
T90 (time spent in SpO2 below 90%)	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

Outcome Measure	Measure Description	Time Frame
AHI (apnea-hypopnea index)	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)	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)	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)	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)	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)	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)	ODI is defined as the number of oxygen decreases ≥3% per hour of sleep.	4 nights

Collaborators and Investigators

• Sponsor: Tsogyal Latshang
• Investigators: Principal Investigator: Tsogyal Latshang, PD Dr. med., Kantonsspital Graubünden

Study record dates

Study Major Dates

• Study Start (Actual): June 30, 2023
• Primary Completion (Actual): March 16, 2024
• Study Completion (Actual): March 16, 2024

Study Registration Dates

• First Submitted: March 15, 2023
• First Submitted That Met QC Criteria: April 12, 2023
• First Posted (Actual): April 24, 2023

Study Record Updates

• Last Update Posted (Actual): February 18, 2026
• Last Update Submitted That Met QC Criteria: February 15, 2026
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Other Study ID 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