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| Name | Class |
|---|---|
| University of Portsmouth | OTHER |
| Vrije Universiteit Brussel | OTHER |
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The aim of this study is to compare the psychophysiological effects of terrestrial altitude with a normobaric, hypoxic situation.
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.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Simulated altitude | Active Comparator | The participants are exposed to simulated altitude in a normobaric situation. |
|
| Terrestrial altitude | Experimental | The participants are exposed to terrestrial altitude in a hypobaric situation. |
|
| Control | No Intervention | the participants are exposed to a normoxic and normobaric environment. |
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Terrestrial altitude | Behavioral | 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. |
| Measure | Description | Time Frame |
|---|---|---|
| Oxygenation of the Brain | 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 | 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 | 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 | 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) |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Ron Clijsen, PhD | University of Applied Sciences and Arts of Southern Switzerland (SUPSI) | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Fachhochschule Südschweiz | Landquart | Kanton Graubünden | 7302 | Switzerland | ||
| University of Applied Sciences and Arts of Southern Switzerland (SUPSI) |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 36355846 | Result | Hohenauer E, Freitag L, Costello JT, Williams TB, Kung T, Taube W, Herten M, Clijsen R. The effects of normobaric and hypobaric hypoxia on cognitive performance and physiological responses: A crossover study. PLoS One. 2022 Nov 10;17(11):e0277364. doi: 10.1371/journal.pone.0277364. eCollection 2022. |
| Label | URL |
|---|---|
| fullversion of publication | View source |
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This is a randomised crossover trials. The same 20 participants were tested in all conditions
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| ID | Title | Description |
|---|---|---|
| FG000 | Experimental: Normobaric Normoxia, Normobaric Hypoxia and Then Hypobaric Hypoxia | Twenty healthy participants completed a cognitive performance test, followed by the modified Harvard-step protocol, in four environments: normobaric normoxia (NN; PiO2: 146.0±1.5mmHg), nor- mobaric hypoxia (NH; PiO2: 100.9±1.3mmHg), hypobaric hypoxia (HH) at the first day of ascent (HH1: PiO2 = 105.6±0.4mmHg) and HH after an overnight stay (HH2: PiO2 = 106.0±0.5mmHg). |
| Title | Milestones | Reasons Not Completed | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall Study |
|
This is a crossover design
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| ID | Title | Description |
|---|---|---|
| BG000 | Experimental: Normobaric Normoxia, Normobaric Hypoxia and Then Hypobaric Hypoxia | Twenty healthy participants completed a cognitive performance test, followed by the modified Harvard-step protocol, in four environments: normobaric normoxia (NN; PiO2: 146.0±1.5mmHg), normobaric hypoxia (NH; PiO2: 100.9±1.3mmHg), hypobaric hypoxia (HH) at the first day of ascent (HH1: PiO2 = 105.6±0.4mmHg) and HH after an overnight stay (HH2: PiO2 = 106.0±0.5mmHg). |
| Units | Counts |
|---|---|
| Participants |
|
| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Continuous | This is a crossover study, using the same 10 women and 10 men (total n=20) in all conditions |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | Oxygenation of the Brain | 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. | Posted | Median | Standard Deviation | percentage of oxygen saturation | Baseline (participants seated for 15 minutes) and during the cognitive performance under normobaric hypoxia, hypobaric hypoxia, and control conditions (mean over time) |
|
From baseline (prior to first experimental condition) through completion of the last experimental condition for each participant (approximately 3 months).
The study was designed witouth a risk for mortality
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | Simulated Altitude | The participants are exposed to simulated altitude in a normobaric situation. 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. |
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| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Dr Erich Hohenauer | Rehabilitation and Exercise Science Laboratory (RES lab), University of Applied Sciences and Arts of Southern Switzerland (SUPSI) | 0041 81 300 01 75 | erich.hohenauer@supsi.ch |
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| Type | Includes Protocol | Includes SAP | Includes ICF | Document Label | Document Date | Document Uploaded Date | Document File Name |
|---|---|---|---|---|---|---|---|
| Prot_SAP | Yes | Yes | No | Study Protocol and Statistical Analysis Plan | May 1, 2019 | Aug 19, 2025 | Prot_SAP_000.pdf |
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| ID | Term |
|---|---|
| D000860 | Hypoxia |
| D000532 | Altitude Sickness |
| ID | Term |
|---|---|
| D012818 | Signs and Symptoms, Respiratory |
| D012816 | Signs and Symptoms |
| D013568 | Pathological Conditions, Signs and Symptoms |
| D012120 | Respiration Disorders |
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The study design is a crossover design.
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|
| Cloud 9 | Behavioral | 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. |
|
| Concentration of Blood Lactate | 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 | 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 | 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 | 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) |
| Landquart |
| Kanton Graubünden |
| 7302 |
| Switzerland |
| Fachhochschule Südschweiz | Landquart | 7302 | Switzerland |
| Mean |
| Standard Deviation |
| years |
|
| Sex: Female, Male | Count of Participants | Participants |
|
| Race and Ethnicity Not Collected | Race and Ethnicity were not collected from any participant. | Count of Participants | Participants |
|
| OG001 | Terrestrial Altitude | The participants are exposed to terrestrial altitude in a hypobaric situation. 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. |
| OG002 | Control | the participants are exposed to a normoxic and normobaric environment. |
|
|
| Primary | Oxygenation of the Blood | 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. | Posted | Mean | Standard Deviation | % SpO2 | 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) |
|
|
|
| Primary | Mean Arterial Pressure | 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. | Posted | Mean | Standard Deviation | mmHg | 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) |
|
|
|
| Primary | Heart Rate | 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. | Posted | Mean | Standard Deviation | beats per minute | at baseline and the end of the submaximal step test (point measurements) |
|
|
|
| Primary | Concentration of Blood Lactate | Lactate measurements are performed by capillary blood measurement. This measurement is taken during the baseline measurements and after the step-up task. | Posted | Mean | Standard Deviation | mmol/l | at the end of 15min baseline period and the end of the step-up test (point measurements) |
|
|
|
| Primary | Sleep Quality | 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. | Posted | Mean | Standard Deviation | score on a scale | Before the cognitive performance test (point measurement) |
|
|
|
| Primary | Altitude Sickness | 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. | Posted | Mean | Standard Deviation | score on a scale | After performing the 3-min step-test (point measurment) |
|
|
|
| Primary | Concentration of Salivary Cortisol | 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. | Posted | Mean | Standard Deviation | μg/l | After each experimental day, in the evening between 8:30 PM and midnight, measured once before participants went to bed (point measurment) |
|
|
|
| 0 |
| 20 |
| 0 |
| 20 |
| 0 |
| 20 |
| EG001 | Terrestrial Altitude | The participants are exposed to terrestrial altitude in a hypobaric situation. 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. | 0 | 20 | 0 | 20 | 0 | 20 |
| EG002 | Control | the participants are exposed to a normoxic and normobaric environment. | 0 | 20 | 0 | 20 | 0 | 20 |
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| D012140 | Respiratory Tract Diseases |
| after 3-min step-test |
|
| 3-min step-test |
|
| 3-min step-test |
|
| 3-min step-test |
|