High temperature

High temperature favours the dissociation of oxy-haemoglobin at the tissues. Heat is a by-product of the metabolic reactions of all cells, and the heat released by contracting muscle fibres tends to raise body temperature. Metabolically active cells liberate more heat. The heat in turn promotes the release of oxygen from oxy-haemoglobin. This shifts the oxygen-haemoglobin dissociation curve to the right. Fever produces a similar result. In contrast, during hypothermia (lowered body temperature) cellular metabolism slows, the need for oxygen is reduced, and more oxygen remains bound to haemoglobin.