The purpose of this study is to determine whether hyperbaric oxygen therapy (HBOT) at 1.75 atmospheres of pressure (ATA) improves cardiovascular fitness (VO₂ max) and reduces inflammation in healthy adults. HBOT involves breathing pure oxygen in a pressurized chamber and is considered investigational for this use.

Recent research has shown that different HBOT pressures can have different effects on inflammation. Specifically, some inflammatory cytokines (measurable markers of inflammation in the body) appear to decrease at low pressures like 1.3 ATA, while a different set of cytokines responds better at higher pressures, such as 2.0 ATA.

Cytokines are small proteins that play a crucial role in cell signaling, particularly within the immune system. They help regulate inflammation, infection response, and overall immune function. While some cytokines promote inflammation to fight off threats, others help reduce inflammation when it's no longer needed. An imbalance in cytokines - especially excessive inflammatory cytokines - can contribute to chronic inflammation, cardiovascular disease, and other health issues.

In this study, we are testing an intermediate pressure - 1.75 ATA - to see if we can target both sets of cytokines at once. If successful, this approach could offer broader anti-inflammatory benefits.

We are also interested in how this intermediate pressure may improve VO₂ max, a key indicator of cardiovascular fitness. Since VO₂ max is strongly linked to heart health and overall longevity, finding a safe and effective way to improve it has meaningful implications not just for athletes, but for anyone looking to enhance their fitness and well-being.

Inclusion Criteria:

• physically active individuals with no history of chronic illness or HBOT exposure within the last three months.

Exclusion Criteria:

• individuals with contraindications to HBOT, including lung diseases or claustrophobia.