Autonomic Activity During Nap Under Hypoxia

Study Overview
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Brief Summary
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Sleeping under hypoxic conditions can impair cognition and autonomic nervous activity. A short daytime nap can modify these changes. Here we propose a randomized, cross-over study to evaluate the heart rate variability during a 90 min nap in a normobaric hypoxic chamber. In addition, we will investigate sleep architecture, vigilance, attention and memory.

Official Title
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Effects of Normobaric Hypoxia on Autonomic Activity During a Nap in Healthy Adults (NAPOXIA)

Conditions
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Hypoxia, Sleep, Healthy

Intervention / Treatment
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* Other: Normoxia
* Other: Hypoxia 1
* Other: Hypoxia 2


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men and women Age 25-45 years BMI 20 - 28 kg/m^2 Exclusion Criteria: Severe, manifest illnesses in need of treatment Postoperative phases Acute and chronic infections Sleep disorders such as sleep apnea, insomnia or somnolence Altitude exposure (> 2500 m asl) within 6 months before enrollment Regular migraines Smoking Athletes Significant weight change within 1 month before enrollment Inability to understand significance and scope of the study Drug or alcohol abuse

Ages Eligible for Study
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Minimum Age: 25 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Normoxia<br>20.9% oxygen | Other: Normoxia<br>* Nap in hypoxia chamber at 20.9% oxygen (36 m asl)<br>|
| Active Comparator: Hypoxia 1<br>15.0% oxygen | Other: Hypoxia 1<br>* Nap in hypoxia chamber at 15.0% oxygen (simulates 2660 m asl)<br>|
| Active Comparator: Hypoxia 2<br>12.8% oxygen | Other: Hypoxia 2<br>* Nap in hypoxia chamber at 12.8% oxygen (simulates 4000 m asl)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart rate variability | Mean RR interval measured by polysomnography (ms) | During 90 minutes nap under normoxic (20.9%) vs. 12.8% hypoxic condition | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart rate variability | Mean RR interval measured by polysomnography (ms) | During 90 minutes nap under normoxic (20.9%) vs. 15.0% hypoxic condition | 
| Sleep Efficiency (SE) | Measured by continuous polysomnography (min) | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 
| Wake After Sleep Onset (WASO) | Measured by continuous polysomnography (min) | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 
| Sleep Onset Latency (SOL) | Measured by continuous polysomnography (min) | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 
| Low Frequency / High Frequency Band | Mean LF/HF ratio measured by continuous ECG | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 
| Standard Deviation 1 / Standard Deviation 2 | Mean SD1/SD2 ratio measured by continuous ECG | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 
| RR intervals longer than 50 ms | Percentage pNN50 measured by continuous ECG (%) | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 
| Core Body Temperature | Mean temperature measured by continuous double sensor monitoring (°C) | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 
| Skin Temperature | Mean temperature measured by continuous double sensor monitoring (°C) | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 
| Digit Span Task | Longest memorized digit series (n, normal range 5-9, higher is better) | After 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 
| Psychomotor Vigilance Task Subscale 1 | Number of lapses (normal range 0-6, higher is worse) | After 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 
| Psychomotor Vigilance Task Subscale 2 | Mean reaction time (normal range 100-500 ms, higher is worse) | After 90 min nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 
| Color Stroope Task Subscale 1 | Number of incongruency errors (normal range 0-5, higher is worse) | After 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 
| Color Stroope Task Subscale 2 | Congruent response time (normal range 400-500 ms, higher is worse) | After 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 
| Color Stroope Task Subscale 3 | Incongruent response time (normal range 600-800 ms, higher is worse) | After 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 
| Color Stroope Task Subscale 4 | Congruent accuracy (above 95% is normal, higher is better) | After 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 
| Color Stroope Task Subscale 5 | Incongruent accuracy (above 85% is normal, higher is better) | After 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Hypoxia, Sleep, Heart rate variability, Sleep architecture