What shifts the O2 dissociation curve to the right?

The oxygen dissociation curve illustrates how readily hemoglobin binds to and releases oxygen under varying conditions. A rightward shift in this curve indicates that hemoglobin's affinity for oxygen decreases, facilitating oxygen release to tissues.

Increased temperature and elevated levels of carbon dioxide (CO2) are the primary factors that can cause a rightward shift. When temperatures rise, hemoglobin's structure changes, leading to a decrease in its oxygen-binding affinity. Similarly, increased CO2 levels promote a process known as the Bohr effect, whereby the presence of more CO2 leads to the release of protons (H+ ions), causing a decrease in pH within the blood. This acidotic environment further reduces hemoglobin's affinity for oxygen, thus encouraging oxygen delivery to metabolically active tissues that require more oxygen, particularly during strenuous activity or in conditions of high metabolic demand.

In summary, the combination of increased temperature and CO2 concentrations effectively enhances tissue oxygenation by encouraging hemoglobin to release oxygen more readily.