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Completed

NCT Number: NCT05826808

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

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.).

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Key information

Conditions

Healthy

Age range

18 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Kantonsspital Graubünden

Chur, Switzerland

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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)

Treatment and study plan

Descent to low altitude

Diagnostic Test

The polysomnographic recordings include electroencephalogram (EEG), electrooculogram (EOG), electromyogram (EMG), electrocardiogram (ECG), pulse oximetry, transcutaneous capnography, nasal airflow and thoracic and abdominal respiratory effort.

Primary outcomes

  1. 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.

Secondary outcomes

  1. 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.

  2. 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.

  3. 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. 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.

  5. 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.

  6. 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.

  7. ODI (oxygen desaturation index)

    Time frame: 4 nights

    ODI is defined as the number of oxygen decreases ≥3% per hour of sleep.

Sponsors and collaborators

Lead sponsor

Tsogyal Latshang

Other

Registry information

Official study title

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

Important dates

Study start
2023
Primary completion
2024
Study completion
2024
First posted
Apr 24, 2023
Registry last updated
Feb 18, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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