The Psychophysiological Effect of Simulated and Terrestrial Altitude
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- Enrollment
- 20
- Locations
- 2
- Primary Endpoint
- Oxygenation of the Brain
Study Overview
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.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Basic Science
- Masking
- Single (Investigator)
Eligibility Criteria
- Ages
- 18 Years to 50 Years (Adult)
- Sex
- All
- Accepts 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
Arms & Interventions
Simulated altitude
The participants are exposed to simulated altitude in a normobaric situation.
Intervention: Cloud 9 (Behavioral)
Terrestrial altitude
The participants are exposed to terrestrial altitude in a hypobaric situation.
Intervention: Terrestrial altitude (Behavioral)
Control
the participants are exposed to a normoxic and normobaric environment.
Outcomes
Primary Outcomes
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.
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.
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.
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.
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.
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.
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.
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.
Secondary Outcomes
No secondary outcomes reported