The Psychophysiological Effect of Simulated and Terrestrial Altitude (Hypoxia)

January 30, 2026 updated by: University of Applied Sciences and Arts of Southern Switzerland
The aim of this study is to compare the psychophysiological effects of terrestrial altitude with a normobaric, hypoxic situation.

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

Research has consistently shown that exposure to extreme environments (such as high altitude stays) may affect cognitive function. For logistical reasons and to control the experimental set-ups, most of these examinations are carried out in the laboratory. By testing under such controlled conditions, researchers can remove any co-foundational factors and isolate the cause of stress, thereby better understanding the mechanisms by which impairment can occur. However, when people are exposed to such environments in the "real world" (such as altitude), they often experience a number of other additional stressors at the same time, which can also affect their performance. Surprisingly, however, little attention has been paid to the study of these additional stressors in combination.

Although the oxygen content remains constant at various altitudes (20.93%), the air pressure decreases exponentially as the altitude increases. As a result, the oxygen partial pressure in arterial blood and tissue is reduced (hypoxia), leading to a deterioration in both physical and cognitive performance. Hypoxic conditions also alter the perception of pain, which may be particularly relevant for patients suffering from hypoxic conditions. According to the authors' knowledge, there is limited literature investigating and comparing simulated and real psychophysiological responses.

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.
20

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
      • Landquart, Switzerland, 7302
        • Fachhochschule Südschweiz
    • Kanton Graubünden
      • Landquart, Kanton Graubünden, Switzerland, 7302
        • Fachhochschule Südschweiz
      • Landquart, Kanton Graubünden, Switzerland, 7302
        • University of Applied Sciences and Arts of Southern Switzerland (SUPSI)

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

18 years to 50 years (Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Healthy, adults aged 18 to 50 years
  • No cardiovascular disease and / or surgery
  • no surgery on the cardiovascular system.
  • No current injuries and / or pain
  • Regular and adequate sleep
  • No terrestrial altitude of 1000 m exceeded last month (including flights)
  • No form of hypoxia exposed last month

Exclusion Criteria:

  • Age over 50 years
  • current injuries of any kind and / or pain
  • Acute and / or chronic pain conditions Known general diseases (e.g., diabetes mellitus)
  • fear of hypoxia
  • fear of heights or sensitivity to terrestrial altitude
  • Regular use of medicines (also bought by yourself), except for contraceptives
  • Cardiovascular diseases or abnormalities
  • Anomalies of the blood analysis or ECG
  • Psychological disorders
  • pregnancy / lactation

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: Basic Science
  • 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.
Active Comparator: Simulated altitude
The participants are exposed to simulated altitude in a normobaric situation.
Behavioral: Cloud 9

Cloud 9 is a solid, certified product that complies with European Directives on Electromagnetic Compatibility, Machine Directive, Air Pressure Equipment and Low Voltage Equipment (89/336 / EEC, 91/368 / CEE, 93/68 / CEE, 97/23 / EC, EN61010-1 All directives are in writing in the Supplements to this Ethics Application.

Simulated height: The subjects are in the laboratory of our institution and are connected to the Cloud 9 by means of a mask. Subjects are exposed to a simulated altitude of 3530m under normobaric conditions. By means of this intervention the psychophysiological effect under normobaric and hypoxic conditions is determined.
Experimental: Terrestrial altitude
The participants are exposed to terrestrial altitude in a hypobaric situation.
Behavioral: Terrestrial altitude
Terrestrial altitude: The volunteers are in an SAC hut at an altitude of 3000 m. By means of this exposure the psychophysiological effect under hypobaric and hypoxic conditions is determined. The subjects spend the night in this SAC hut and the measurements are repeated the next day.
No Intervention: Control
the participants are exposed to a normoxic and normobaric environment.

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
Oxygenation of the Brain
Time Frame: Baseline (participants seated for 15 minutes) and during the cognitive performance under normobaric hypoxia, hypobaric hypoxia, and control conditions (mean over time)
Brain oxygen saturation is measured non-invasively using a deep tissue oxygenation monitor (moorVMS-NIRS, moor instruments, www.moor.co.uk). For this purpose, adhesive electrodes are applied over the muscle and the forehead. This measurement is taken during the baseline measurements, and during the cognitive performance test. This outcome measure reports the change from baseline for the oxygenation of the brain.
Baseline (participants seated for 15 minutes) and during the cognitive performance under normobaric hypoxia, hypobaric hypoxia, and control conditions (mean over time)
Oxygenation of the Blood
Time Frame: Continuously during the 15-minute seated baseline period before each trial (mean over 15min) and at the end of the step-up test (point measurement)
The oxygen saturation of the blood (SpO2) is measured with a portable pulse oximeter with finger clip probe (Nonin 7500, Nonin medical B.V., Plymouth, USA). This measurement is taken during the baseline measurements and after the step-up task. This outcome measure reports the change from baseline for the oxygenation of the blood.
Continuously during the 15-minute seated baseline period before each trial (mean over 15min) and at the end of the step-up test (point measurement)
Mean Arterial Pressure
Time Frame: At the end of the 15-minute baseline seated period before each trial and at the end of the 3-minute submaximal step-test (Point measurements)

Blood pressure was measured using an automated sphygmomanometer monitor from the left brachial artery. MAP was calculated using the following formula:

MAP = diastolic blood pressure + (systolic blood pressure-diastolic blood pressure) / 3.
At the end of the 15-minute baseline seated period before each trial and at the end of the 3-minute submaximal step-test (Point measurements)
Heart Rate
Time Frame: at baseline and the end of the submaximal step test (point measurements)
The heart rate is measured using a pulse belt and an additional 2-point ECG (Actiheart, Camntech Ltd., Cambridge, UK). This measurement is taken during the baseline measurements and after the step-up task. This outcome measure reports the change from baseline for the heart rate.
at baseline and the end of the submaximal step test (point measurements)
Concentration of Blood Lactate
Time Frame: at the end of 15min baseline period and the end of the step-up test (point measurements)
Lactate measurements are performed by capillary blood measurement. This measurement is taken during the baseline measurements and after the step-up task.
at the end of 15min baseline period and the end of the step-up test (point measurements)
Sleep Quality
Time Frame: Before the cognitive performance test (point measurement)
Sleep quality of the night before the experimental day was assessed using the validated and reliable GSQS, consisting of a 16-item true or false questionnaire. GSQS scores ranged from 0 to 16 whereas higher scores indicated lower subjective sleep quality.
Before the cognitive performance test (point measurement)
Altitude Sickness
Time Frame: After performing the 3-min step-test (point measurment)
Altitude sickness is measured with "Lake Louis acute mountain sickness scale", choosing the most appropriate answer from 5 questions. Questions range from 0 (=no symptoms) to 4 (=severe symptoms). LLAMS symptoms were assessed at the end of each experimental measurement.
After performing the 3-min step-test (point measurment)
Concentration of Salivary Cortisol
Time Frame: After each experimental day, in the evening between 8:30 PM and midnight, measured once before participants went to bed (point measurment)
Salivary cortisol was assessed from the n = 10 female participants to assess the daily stress level after each experimental day. Through a straw, 3mL of saliva was collected and stored in a refrigerator until the analyses were performed the next day using the enzyme-linked immunosorbent assay (ELISA) method.
After each experimental day, in the evening between 8:30 PM and midnight, measured once before participants went to bed (point measurment)

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
Thermal comfort and sensation
Time Frame: 30 minutes
These parameters are measured by a thermal comfort scale (ranging from 0 [comfortable] to +4 [very uncomfortable]) and a thermal sensation scale (ranging from -4 [ver cold] to +4 [very hot]). These measurements are performed after the baseline measurement and after the cold water bath immersion of the hand and report the change from baseline.
30 minutes

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.
University of Applied Sciences and Arts of Southern Switzerland

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Vrije Universiteit Brussel
University of Portsmouth

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: Ron Clijsen, PhD, University of Applied Sciences and Arts of Southern Switzerland (SUPSI)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

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 24, 2019

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 31, 2021

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.
April 30, 2022

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).
August 7, 2019

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.
August 29, 2019

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.
August 30, 2019

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 19, 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.
January 30, 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.
January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

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.
  • 2019-00504

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

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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