What happens to hemoglobin at higher carbon dioxide levels?

Hemoglobin exhibits a right shift in the oxygen dissociation curve at higher levels of carbon dioxide, a phenomenon known as the Bohr effect. This shift indicates that hemoglobin's affinity for oxygen decreases in the presence of elevated carbon dioxide levels. The physiological rationale behind this is important for oxygen transport: as tissues produce more carbon dioxide during metabolism, it causes the pH of the blood to lower (become more acidic). Consequently, hemoglobin changes its conformation to release more oxygen into the tissues that need it most.

In a right-shifted curve, for any given partial pressure of oxygen, hemoglobin is less saturated than it would be at lower carbon dioxide levels. This adaptation is crucial for efficient oxygen delivery in actively metabolizing tissues where both carbon dioxide and hydrogen ions (resulting from increased metabolism and decreased pH) are produced. Thus, an increase in carbon dioxide not only facilitates the release of oxygen but also enhances the overall efficiency of gas exchange in the body.