What effect does a low pH (high H+) have on the O2 dissociation curve?

A low pH, which indicates a high concentration of hydrogen ions (H+), leads to a rightward shift in the oxygen dissociation curve. This phenomenon is known as the Bohr effect, where increased acidity (lower pH) enhances the release of oxygen from hemoglobin.

In a more acidic environment, hemoglobin's affinity for oxygen decreases, meaning that it is more likely to release oxygen to tissues that are in need. This is particularly important during situations of increased metabolic activity, such as exercise or in tissues that are undergoing inflammation, where carbon dioxide levels are higher, leading to a drop in pH.

As a result, a rightward shift indicates that at any given partial pressure of oxygen, hemoglobin is less saturated with oxygen, facilitating better oxygen delivery to the tissues. This adaptation is crucial for maintaining adequate oxygen supply to areas where it is most required, especially under stress or during increased metabolic demands.