Oxygen sensing is the process by which organisms detect and respond to changes in oxygen levels in their environment. This ability is crucial for maintaining cellular functions and overall health. Specialized cells, such as those found in the lungs and blood vessels, play a key role in monitoring oxygen concentrations and signaling the body to adjust its functions accordingly. In humans, oxygen sensing is primarily managed by hypoxia-inducible factors (HIFs), which are proteins that help regulate gene expression in response to low oxygen levels. When oxygen is scarce, HIFs activate genes that promote adaptation, such as increasing red blood cell production and enhancing blood flow to tissues, ensuring that the body can cope with varying oxygen availability.