Oxygen (100% concentration) – Pure oxygen administered as a medical gas. This therapy involves breathing in oxygen at high concentration levels. It’s commonly used to increase the amount of oxygen in the blood. During this study, researchers are examining how this high concentration of oxygen affects blood flow and blood vessel resistance in different parts of the body, including the heart, lungs, and throughout the circulatory system.

Pulmonary Hypertension – A condition where blood pressure in the pulmonary arteries becomes abnormally high. The pulmonary arteries carry blood from the heart to the lungs. This increased pressure makes it harder for the heart to pump blood through the lungs. The blood vessels in the lungs become narrowed and thickened over time.

Coronary Microvascular Dysfunction – A condition affecting the small coronary blood vessels that branch off from the larger coronary arteries. These tiny vessels don’t function properly, leading to reduced blood flow to the heart muscle. The small blood vessels may not dilate properly or may have irregular contractions.

Hypoxia – A condition where the body or a specific part of the body doesn’t receive enough oxygen. It occurs when oxygen levels in the blood fall below normal levels. The body’s tissues need oxygen to function properly, and when oxygen levels are too low, cells begin to work less efficiently.

Heart Failure – A chronic condition where the heart cannot pump blood effectively enough to meet the body’s needs. The heart muscle becomes too weak or stiff to work properly. This leads to fluid buildup in the lungs and body tissues, causing symptoms such as shortness of breath and swelling.