Hypoxia, Altitude, Appetite, Energy Intake
Conditions
Brief summary
The goal of this clinical trial is to investigate the effects of acute passive continuous hypoxemia (simulated high-altitude at rest) on appetite and energy intake in healthy young female adults. The main questions it aims to answer are: * Does six hours of simulated high-altitude (5000 meters) reduce scores of subjective appetite and energy intake? * Do changes in appetite and energy intake persist in the hours following the end of hypoxic exposure? Researchers will compare the effects of simulated high-altitude to a control normoxia (sea-level) condition to see if exposure to low oxygen levels independently affect appetite and energy intake. Participants will: * Visit the laboratory for a preliminary screening session to assess eligibility. * Undergo two randomized, single-blind, experimental sessions consisting of six hours of passive exposure to normoxia or hypoxia in a climate-controlled chamber. * Consume foods provided from a curated list, served in ad libitum quantities, after leaving the laboratory to assess post-exposure energy intake.
Interventions
OTHERNormoxia
Participants will undergo a 6-hour passive exposure to normoxia in a climate-controlled environmental chamber maintained at 22°C with 30% relative humidity. They will remain in a fasted state throughout the exposure period.
OTHERHypoxia (simulated altitude of 5000 meters above sea-level)
Participants will undergo a 6-hour passive exposure to a simulated altitude of 5000 meters above sea-level in a climate-controlled environmental chamber maintained at 22°C with 30% relative humidity. They will remain in a fasted state throughout the exposure period.
Sponsors
University of Ottawa
Natural Sciences and Engineering Research Council, Canada
Hopital Montfort
Institut du Savoir Montfort
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 30 Years
Healthy volunteers
Yes
Inclusion criteria
* English or French speaking * Ability to provide informed consent
Exclusion criteria
* History or evidence of chronic disease * Current use of hypolipemic medication * Current use of hormonal contraceptives * Current use of antidepressants * Current use of anticoagulants * Ongoing smoking status * Experiencing pregnancy, puerperium, or irregular menstrual cycles
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change from baseline in desire to eat | Baseline and 6 hours; Baseline and 24 hours | Scores of subjective desire to eat, measured using visual analog scales. Measurements are performed upon arrival at the laboratory (baseline), hourly during the exposure, immediately after a 30-minute ad libitum buffet, immediately before bedtime, and 24 hours after the baseline measurement. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Heart rate | 6 hours | Measured continuously throughout the exposure. |
| Oxyhemoglobin saturation | 6 hours | Measured continuously throughout the exposure. |
| Change from baseline in hunger | Baseline and 6 hours; Baseline and 24 hours | Scores of subjective hunger, measured using visual analog scales. Measurements are performed upon arrival at the laboratory (baseline), hourly during the exposure, immediately after a 30-minute ad libitum buffet, immediately before bedtime, and 24 hours after the baseline measurement. |
| Systolic blood pressure | 6 hours | Measured upon arrival at the laboratory (baseline), hourly during the exposure, and immediately after eating. |
| Change from baseline in fullness | Baseline and 6 hours; Baseline and 24 hours | Scores of subjective fullness, measured using visual analog scales. Measurements are performed upon arrival at the laboratory (baseline), hourly during the exposure, immediately after a 30-minute ad libitum buffet, immediately before bedtime, and 24 hours after the baseline measurement. |
| Diastolic blood pressure | 6 hours | Measured upon arrival at the laboratory (baseline), hourly during the exposure, and immediately after eating. |
| Change from baseline in prospective food consumption | Baseline and 6 hours; Baseline and 24 hours | Scores of subjective prospective food consumption, measured using visual analog scales. Measurements are performed upon arrival at the laboratory (baseline), hourly during the exposure, immediately after a 30-minute ad libitum buffet, immediately before bedtime, and 24 hours after the baseline measurement. |
| Lake Louise Acute Mountain Sickness Score | 6 hours | Peak score on the Lake Louise Acute Mountain Sickness questionnaire, measured upon arrival at the laboratory (baseline), hourly during the exposure, and immediately after eating. |
| Energy intake immediately after 6 hours of exposure (buffet) | Hour 6 of exposure | Energy intake in the laboratory during a 30-minute ad libitum buffet immediately after 6 hours of exposure, administered using a validated food menu (McNeil, 2012) and analyzed using the Food Processor SQL from ESHA Research, Inc. |
| Fluid consumption during exposure | 6 hours | Average hourly fluid consumption calculated by weighing participant water intake at the start and end of each hour of exposure (normalized to the exposure duration). |
| Energy intake post-buffet | 6.5 hours of exposure and 24 hours | Energy intake outside the laboratory between end-buffet and bedtime, administered using a validated food menu (McNeil, 2012) and analyzed using the Food Processor SQL from ESHA Research, Inc. |
| Change from baseline in explicit liking using the LFPQ | Baseline and 6.5 hours of exposure | Explicit liking will be measured using the Leeds Food Preference Questionnaire. Measurements will be taken upon arrival at the laboratory (baseline), following 5 hours of exposure, and after a 30-min ad libitum buffet. |
| Change from baseline in explicit wanting using the LFPQ | Baseline and 6.5 hours of exposure | Explicit wanting will be measured using the Leeds Food Preference Questionnaire. Measurements will be taken upon arrival at the laboratory (baseline), following 5 hours of exposure, and after a 30-min ad libitum buffet. |
| Change from baseline in implicit wanting using the LFPQ | Baseline and 6.5 hours of exposure | Implicit wanting will be measured using the Leeds Food Preference Questionnaire. Measurements will be taken upon arrival at the laboratory (baseline), following 5 hours of exposure, and after a 30-min ad libitum buffet. |
| Change from baseline in olfaction | Baseline and Hour 4 of exposure | Olfaction will be measured using the Sniffin' Sticks (Burghart Instruments, Wedel, Germany), a 3-test battery of odorized markers that measure odor detection threshold, odor discrimination, and odor identification. Measurements will be performed upon arrival at the laboratory (baseline) and following 4 hours of exposure. |
| Change from baseline in gustation | Baseline and Hour 4 of exposure | Olfaction will be measured using Taste Strips (Burghart Instruments, Wedel, Germany). Measurements will be performed upon arrival at the laboratory (baseline) and following 4 hours of exposure. |
| Change from baseline in resting energy expenditure | Baseline and Hour 5 of exposure | Resting energy expenditure will be measured via indirect calorimetry upon arrival at the laboratory (baseline) and following 5 hours of exposure. |
| Change from baseline in respiratory exchange ratio | Baseline and Hour 5 of exposure | Respiratory exchange ratio will be measured via indirect calorimetry upon arrival at the laboratory (baseline) and following 5 hours of exposure. |
| Change from baseline in plasma glucose concentrations | 6 hours | Plasma glucose concentrations will be measured via colorimetric assays from venous blood samples collected upon arrival at the laboratory (baseline) and hourly during the exposure (i.e., 0 or baseline, 60, 120, 180, 240, 300, and 360 minutes). |
| Change from baseline in plasma insulin concentrations | 6 hours | Plasma insulin concentrations will be measured via colorimetric assays from venous blood samples collected upon arrival at the laboratory (baseline) and hourly during the exposure (i.e., 0 or baseline, 60, 120, 180, 240, 300, and 360 minutes). |
| Change from baseline in plasma non-esterified fatty acid concentrations | 6 hours | Plasma non-esterified fatty acid concentrations will be measured via colorimetric assays from venous blood samples collected upon arrival at the laboratory (baseline) and hourly during the exposure (i.e., 0 or baseline, 60, 120, 180, 240, 300, and 360 minutes). |
| Change from baseline in plasma triglyceride concentrations | 6 hours | Plasma triglyceride concentrations will be measured via colorimetric assays from venous blood samples collected upon arrival at the laboratory (baseline) and hourly during the exposure (i.e., 0 or baseline, 60, 120, 180, 240, 300, and 360 minutes). |
| Change from baseline in plasma beta-hydroxybutyrate concentrations | 6 hours | Plasma beta-hydroxybutyrate concentrations will be measured via colorimetric assays from venous blood samples collected upon arrival at the laboratory (baseline) and hourly during the exposure (i.e., 0 or baseline, 60, 120, 180, 240, 300, and 360 minutes). |
Countries
Canada
Outcome results
None listed