An interventional study of Sleep Deprivation and Caffeine in Oxygen Toxicity, Hypercapnia and Seizures, sponsored by Duke University. Recruiting at 1 site in United States. Open to participants aged 18 Years to 45 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-21.
Sponsored by Duke University · Not applicable, Interventional, and Prevention
The goal of this clinical trial is to learn about the mechanisms of oxygen toxicity in scuba divers. The main questions it aims to answer are:
Participants will be asked to do the following:
Researchers will compare the performance of each subject before and after the possible interventions described above to see if there are changes in exercise performance, respiratory function, cerebral blood flow, and levels of gene expression.
156 studies on the registry are indexed under Hypercapnia; 31 are open to participants now.
This study's planned enrollment of 62 is above the median of 36 across 120 interventional studies indexed under Hypercapnia.
Browse Hypercapnia studies →Duke University is the lead sponsor of 2,063 studies on the registry; 273 are open to participants now.
Of its 204 completed or terminated interventional studies of FDA-regulated products, 167 (82%) have results posted.
Counted across the registry records on this site, refreshed daily.
The criteria were revised on the registry on Oct 7, 2026. See what changed
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Effect of sleep deprivation on HCVR and arterial PCO2 during submersed rest and exercise at 98 fsw. Ten subjects will be tested before and after 24 hours of sleep deprivation. The order of sleep deprivation vs. control will be randomized. Measurements at 98 fsw will be obtained at rest and during 10 minutes of moderate exercise in thermoneutral (29-30°C) water.
Behavioral: Sleep Deprivation
Effect of caffeine and methylphenidate on HCVR and arterial PCO2 during submersed rest and exercise at 98 fsw. Twenty subjects will be similarly sleep-deprived, tested as above and then re-tested tested following oral administration of administration of either oral caffeine (N=10) or methylphenidate (N=10). Pre-dive caffeine will be administered 500 mg orally \[59\]. Pre-dive methylphenidate will be administered as a single dose of 5 mg \[60\]. The order of drug administration vs. control will be randomized. Measurements at 98 fsw will be obtained at rest and during 10 minutes of moderate exercise in thermoneutral (29-30°C) water. fNIRS will be used to assess cerebral oxygenation and regional blood volume.
Drug: Caffeine
Effect of caffeine and methylphenidate on HCVR and arterial PCO2 during submersed rest and exercise at 98 fsw. Twenty subjects will be similarly sleep-deprived, tested as above and then re-tested tested following oral administration of administration of either oral caffeine (N=10) or methylphenidate (N=10). Pre-dive caffeine will be administered 500 mg orally \[59\]. Pre-dive methylphenidate will be administered as a single dose of 5 mg \[60\]. The order of drug administration vs. control will be randomized. Measurements at 98 fsw will be obtained at rest and during 10 minutes of moderate exercise in thermoneutral (29-30°C) water. fNIRS will be used to assess cerebral oxygenation and regional blood volume.
Drug: Methylphenidate
Effect of simulated chronic CO2 exposure on HCVR and arterial PCO2 during submersed rest and exercise at 98 fsw. Ten subjects will be studied before and after induction of metabolic alkalosis as described above with daily oral administration of sodium bicarbonate. Oral bicarbonate to simulate hypercapnia exposure will seek to increase serum bicarbonate to 30 mM/L via daily oral intake of 6 teaspoons of NaHCO3 for five days. Subsequently, blood will be drawn and intake adjusted as necessary \[61\]. The order of alkalization vs. control will be randomized. Measurements at 98 fsw will be obtained at rest and during 10 minutes of moderate exercise in thermoneutral (29-30°C) water.
Drug: Sodium bicarbonate
24 hours sleep deprivation
Oral administration of caffeine
Oral administration of methylphenidate
Oral administration of sodium bicarbonate to simulate carbon dioxide exposure
Hypercapnic ventilatory response
Time frame: 3 months
Lactate, pyruvate
Time frame: 3 months
Arterial PCO2
Time frame: Baseline and after Intervention/arm
Integrated diaphragmatic function (IDF) composite score
A composite score comprised of maximum breathing capacity (MBC), maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), and diaphragmatic thickness will be used as the measure of Integrated diaphragmatic function (IDF).
Time frame: Baseline and after Intervention/arm, which averages 3 months
Cerebral blood oxygenation
Time frame: Baseline and after Intervention/arm, which averages 3 months
Hormone levels (leptin, adiponectin)
Time frame: Baseline and after Intervention/arm, which averages 3 months
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
Pending-funding
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drugs tested here: Caffeine · Methylphenidate · Sodium Bicarbonate