Autonomic Activity During Nap Under Hypoxia (NAPOXIA)

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

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.

Study Overview

• Status: Completed
• Conditions: Healthy; Hypoxia; Sleep
• Intervention / Treatment: Other: Normoxia; Other: Hypoxia 1; Other: Hypoxia 2

• Study Type: Interventional
• Enrollment (Actual): 16
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Germany
  • Berlin, Germany, 13125
    • Experimental & Clinical Research Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 25 years to 45 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

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

What is the study measuring?

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%)

Collaborators and Investigators

• Sponsor: Charite University, Berlin, Germany
• Investigators: Principal Investigator: Alain Riveros, MD, Charite University, Berlin, Germany

Publications and helpful links

General Publications

• Riveros-Rivera A, Penzel T, Gunga HC, Opatz O, Paul F, Klug L, Boschmann M, Mahler A. Hypoxia Differentially Affects Healthy Men and Women During a Daytime Nap With a Dose-Response Relationship: a Randomized, Cross-Over Pilot Study. Front Physiol. 2022 May 24;13:899636. doi: 10.3389/fphys.2022.899636. eCollection 2022.

Helpful Links

• Results publication

Study record dates

Study Major Dates

• Study Start (Actual): October 30, 2019
• Primary Completion (Actual): December 30, 2020
• Study Completion (Actual): December 30, 2020

Study Registration Dates

• First Submitted: October 25, 2019
• First Submitted That Met QC Criteria: October 30, 2019
• First Posted (Actual): October 31, 2019

Study Record Updates

• Last Update Posted (Actual): July 11, 2022
• Last Update Submitted That Met QC Criteria: July 7, 2022
• Last Verified: July 1, 2022

More Information

Terms related to this study

• Keywords: Sleep; Hypoxia; Heart rate variability; Sleep architecture
• Additional Relevant MeSH Terms: Signs and Symptoms, Respiratory; Hypoxia
• Other Study ID Numbers: NAPOXIA

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Yes
• IPD Plan Description: Individual participant data that underlie the results of reported articles (text, tables, figures, supplemental data) will be shared after deidentification.
• IPD Sharing Time Frame: Beginning 9 months and ending 36 months following article publication.
• IPD Sharing Access Criteria: Researchers who provide a methodologically sound proposal.
• IPD Sharing Supporting Information Type: Study Protocol

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No