HIF-α, or Hypoxia-Inducible Factor alpha, is a protein that plays a crucial role in how cells respond to low oxygen levels, a condition known as hypoxia. It helps regulate various genes that are involved in processes like energy metabolism, blood vessel formation, and cell survival. HIF-α is essential for adapting to changes in oxygen availability, which can occur during exercise or in certain diseases. When oxygen levels are normal, HIF-α is quickly broken down. However, under low oxygen conditions, it stabilizes and accumulates in the cell, allowing it to activate genes that help the body cope with the lack of oxygen. This mechanism is vital for maintaining proper function in tissues and organs, especially in conditions like cancer and cardiovascular diseases.