Effects of Melatonin on Sleep, Ventilatory Control and Cognition at Altitude.

Early Phase 1

Completed

• Conditions: Sleep; Altitude Hypoxia; Oxidative Stress; Neurocognitive Dysfunction; Ventilation
• Interventions: Other: Hypoxia; Dietary Supplement: Melatonin

• Registration Number: NCT03368352
• Lead Sponsor: University of California, San Diego

Brief Summary

Low oxygen at altitude causes pauses in breathing during sleep, called central sleep apnea. Central sleep apnea causes repeated awakenings and poor sleep. Low oxygen itself and the induced oxidative stress can damage mental function which is likely worsened by poor sleep. Reduced mental function due to low oxygen can pose a serious danger to mountain climbers. However there is also mounting evidence that even in populations of people that live at high altitudes and are considered adapted, low oxygen contributes to reductions in learning and memory. Therefore there is a serious need for treatments which may improve sleep, control of breathing and mental function during low oxygen. Melatonin is a hormone produced in the brain during the night which regulates sleep patterns with strong antioxidant and anti-inflammatory properties. A study previously reported that melatonin taken 90 mins before bed at 4,300 m (14,200 ft) induced sleep earlier, reduced awakenings and improved mental performance the following day. However how melatonin caused these effects was not determined. Therefore this study aims to determine how melatonin effects control of breathing, sleep and mental performance during exposure to low oxygen.

Detailed Description

Not available

Study Timeline

• Study Start: 2017-07-04
• Study First Submitted: 2017-11-20
• Study First Submitted QC: 2017-12-04
• Study First Posted: 2017-12-11
• Primary Completion: 2018-12-20
• Study Completion: 2018-12-20
• Status Verified: 2019-01
• Last Update Submitted: 2019-01-29
• Last Update Posted: 2019-01-31

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

Exclusion Criteria

• Sleep disorders
• Pregnant females
• Smokers (quit ≥ 1 year ago acceptable)
• Any known cardiac (apart from treated hypertension with acceptable drugs, see below), pulmonary (including asthma), renal, neurologic (including epilepsy), neuromuscular, hepatic disease, or patients with diabetes.
• Prior or current use of melatonin.
• Use of any medications that may affect sleep or breathing, blood-thinning medications (anticoagulants), antioxidants, anti-inflammatories, medications that suppress the immune system (immunosuppressants), diabetes medications and birth control pills.
• A psychiatric disorder, other than mild depression; e.g. schizophrenia, bipolar disorder, major depression, panic or anxiety disorders.
• Substantial alcohol (>3oz/day) or use of illicit drugs.
• Previous occurrence of high altitude pulmonary or cerebral edema.
• Recent exposure to altitude (>8000ft) in the last month or having slept at an altitude >6000ft in the last month.
• Inability to provide written informed consent or able to complete the experiment.
• Non-English speakers (necessary to complete neurocognitive testing).
• More than 10 cups of beverages with caffeine (coffee, tea, soda/pop) per day.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Hypoxia with Placebo	Hypoxia	Sleep in hypoxic tent after taking Placebo 1 hour before bed.
Hypoxia with Melatonin	Melatonin	Sleep in hypoxic tent after taking 5 mg Melatonin before bed.

Primary Outcome Measures

Name	Time	Method
Neurocognitive function	30 minutes after arousal from sleep	Stroop-color word test median number of errors. Higher numbers indicate worse performance.
Endothelial function	5 minutes after arousal from sleep	Reactive hypermedia index via EndoPat
Lipid peroxidation in serum	immediately after arousal from sleep	Concentration of Malondialdehyde in serum samples
Hypercapnic hypoxic ventilatory sensitivity	1 hour after arousal from sleep	This is the one outcome. It is the gain of the ventilatory response to changes in CO2, during sustained hypoxia. Delta minute ventilation / delta mmHg CO2 during sustained hypoxia

Trial Locations

Locations (1)

UCSD Sleep Lab; 🇺🇸 San Diego, California, United States