Oxygen Toxicity: Mechanisms in Humans

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:

* How does the training of respiratory muscles affect oxygen toxicity? * How do environmental factors, such as sleep deprivation, the ingestion of commonly utilized medications, and chronic exposure to carbon dioxide, impact the risk of oxygen toxicity? * How does immersion in water affect the development of oxygen toxicity?

Participants will be asked to do the following:

* Undergo a basic screening exam composed of health history, vital signs, and some respiratory function tests * Train their respiratory muscles at regular intervals * Exercise on a cycle ergometer both in dry conditions and underwater/under pressure in the context of medication, sleep deprivation, or carbon dioxide exposure

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.