Hypoxia, Sleep, Healthy
Conditions
Keywords
Hypoxia, Sleep, Heart rate variability, Sleep architecture
Brief summary
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.
Interventions
OTHERNormoxia
Nap in hypoxia chamber at 20.9% oxygen (36 m asl)
OTHERHypoxia 1
Nap in hypoxia chamber at 15.0% oxygen (simulates 2660 m asl)
OTHERHypoxia 2
Nap in hypoxia chamber at 12.8% oxygen (simulates 4000 m asl)
Sponsors
Charite University, Berlin, Germany
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
25 Years to 45 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Heart rate variability | During 90 minutes nap under normoxic (20.9%) vs. 12.8% hypoxic condition | Mean RR interval measured by polysomnography (ms) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Sleep Efficiency (SE) | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Measured by continuous polysomnography (min) |
| Wake After Sleep Onset (WASO) | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Measured by continuous polysomnography (min) |
| Sleep Onset Latency (SOL) | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Measured by continuous polysomnography (min) |
| Low Frequency / High Frequency Band | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Mean LF/HF ratio measured by continuous ECG |
| Standard Deviation 1 / Standard Deviation 2 | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Mean SD1/SD2 ratio measured by continuous ECG |
| RR intervals longer than 50 ms | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Percentage pNN50 measured by continuous ECG (%) |
| Core Body Temperature | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Mean temperature measured by continuous double sensor monitoring (°C) |
| Skin Temperature | During 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Mean temperature measured by continuous double sensor monitoring (°C) |
| Heart rate variability | During 90 minutes nap under normoxic (20.9%) vs. 15.0% hypoxic condition | Mean RR interval measured by polysomnography (ms) |
| Psychomotor Vigilance Task Subscale 1 | After 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Number of lapses (normal range 0-6, higher is worse) |
| Psychomotor Vigilance Task Subscale 2 | After 90 min nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Mean reaction time (normal range 100-500 ms, higher is worse) |
| Color Stroope Task Subscale 1 | After 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Number of incongruency errors (normal range 0-5, higher is worse) |
| Color Stroope Task Subscale 2 | After 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Congruent response time (normal range 400-500 ms, higher is worse) |
| Color Stroope Task Subscale 3 | After 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Incongruent response time (normal range 600-800 ms, higher is worse) |
| Color Stroope Task Subscale 4 | After 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Congruent accuracy (above 95% is normal, higher is better) |
| Color Stroope Task Subscale 5 | After 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Incongruent accuracy (above 85% is normal, higher is better) |
| Digit Span Task | After 90 minutes nap under normoxic (20.9%) vs. two hypoxic conditions (12.8 and 15%) | Longest memorized digit series (n, normal range 5-9, higher is better) |
Countries
Germany
Outcome results
None listed