Ketogenic Diet for Reduction of CNS Oxygen Toxicity in Working Divers

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.