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The Psychophysiological Effect of Simulated and Terrestrial Altitude

The Psychophysiological Effect of Simulated and Terrestrial Altitude

Status
Completed
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT04075565
Acronym
Hypoxia
Enrollment
20
Registered
2019-08-30
Start date
2019-06-24
Completion date
2022-04-30
Last updated
2026-02-19

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

Conditions

Altitude, Altitude Hypoxia, Altitude Sickness, Hypoxia, Hypoxia, Altitude, Mountain Sickness

Keywords

hypoxia, altitude, physiology, cognition

Brief summary

The aim of this study is to compare the psychophysiological effects of terrestrial altitude with a normobaric, hypoxic situation.

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.

Interventions

BEHAVIORALTerrestrial 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.

BEHAVIORALCloud 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.

Sponsors

University of Applied Sciences and Arts of Southern Switzerland
Lead SponsorOTHER
University of Portsmouth
CollaboratorOTHER
Vrije Universiteit Brussel
CollaboratorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Investigator)

Intervention model description

The study design is a crossover design.

Eligibility

Sex/Gender
ALL
Age
18 Years to 50 Years
Healthy volunteers
Yes

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

Design outcomes

Primary

MeasureTime frameDescription
Oxygenation of the BrainBaseline (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.
Oxygenation of the BloodContinuously 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.
Mean Arterial PressureAt 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.
Heart Rateat 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.
Concentration of Blood Lactateat 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.
Sleep QualityBefore 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.
Altitude SicknessAfter 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.
Concentration of Salivary CortisolAfter 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.

Countries

Switzerland

Contacts

PRINCIPAL_INVESTIGATORRon Clijsen, PhD

University of Applied Sciences and Arts of Southern Switzerland (SUPSI)

Participant flow

Recruitment details

This is a randomised crossover trials. The same 20 participants were tested in all conditions

Baseline characteristics

Characteristic
Age, Continuous
Females
24.8 years
STANDARD_DEVIATION 5.1
Age, Continuous
Males
30.3 years
STANDARD_DEVIATION 6.3
Sex: Female, Male
Female
10 Participants
Sex: Female, Male
Male
10 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
EG002
affected / at risk
deaths
Total, all-cause mortality
0 / 200 / 200 / 20
other
Total, other adverse events
0 / 200 / 200 / 20
serious
Total, serious adverse events
0 / 200 / 200 / 20

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 20, 2026