Ketogenic Diet for Reduction of CNS Oxygen Toxicity in Working Divers

Study Overview
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Brief Summary
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The purpose of this research study is to understand the effect of nutritional ketosis on CNS oxygen toxicity in undersea divers. The investigators hope this will provide a starting point to develop methods for improving the safety of Navy divers, warfighters and submariners.

Detailed Description
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Participants in the study will undergo a physical exam and testing as well as training on cognitive testing software as part of the screening process. Eligible subjects will be assigned a normal diet or a ketogenic diet (a diet high in fat/protein and low in carbohydrates) for three days before testing. Subjects will be immersed in water to the shoulders, inside a hyperbaric (high pressure) chamber while breathing 100% oxygen at increased atmospheric pressure, and doing cycling exercise. Testing on the cognitive software, as well as blood sampling and physical monitoring will be done while in the chamber. All tests and procedures will be completed again at least one week later with the diet not assigned for the first session.

Official Title
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Ketogenic Diet for Reduction of Oxygen Toxicity in Working Divers

Conditions
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CNS Oxygen Toxicity, Ketogenic Diet

Intervention / Treatment
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* Dietary Supplement: Ketogenic Diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Males & females between 18 and 50 years old Able to pedal a bicycle ergometer continuously for 15 minutes Non-smoker No history of cardiovascular disease, including coronary artery disease, valvular disease, cardiomyopathy or hypertension. No history of lung disease Exclusion Criteria: Prolonged QTc on initial ECG Currently pregnant or attempting to become pregnant. Have a history of: Smoking Coronary artery disease Hypertension Seizures Exercise intolerance Psychiatric disorder Previous pneumothorax or pneumomediastinum Hypo or hyperglycemia Diabetes Regularly take any medications which may alter heart rate, blood pressure, neurotransmitter function, mood or affect.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 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: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Each subject will randomize to one of two arms and will crossover to the other arm at least one week later.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Normal Diet<br>The participant will eat their usual diet for at least 72 hrs prior to the experiment, document their diet during that time and be tested for ketone level immediately prior to the experiment. | |
| Experimental: Ketogenic Diet<br>The participant will follow a ketogenic diet for 72 hrs prior to the experiment and consume a ketone supplement 60 minutes prior to the experiment. They will document their diet and be tested for ketone level immediately prior to the experiment. | Dietary Supplement: Ketogenic Diet<br>* Eat a ketogenic diet (low carbohydrate, high fat diet) for 72 hrs prior to the experiment and consume a dietary ketone supplement 60 minutes before the experiment.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to First Manifestations of CNS Oxygen Toxicity | Time to the first manifestation of CNS Oxygen Toxicity: visual or hearing changes, nausea, twitching, irritability, dizziness, convulsions or change consistent with possible CNS Oxygen Toxicity. | 2 hrs |