Final answer:
A fever does indeed decrease the affinity of haemoglobin for oxygen, mainly because higher body temperatures lead to greater dissociation of oxygen from haemoglobin, making it more available to active tissues in need of oxygen.
Step-by-step explanation:
The question 'A fever may decrease haemoglobin's affinity for oxygen.' can be answered by understanding how haemoglobin's oxygen-binding capacity is influenced by various factors. One crucial factor that affects hemoglobin's oxygen affinity is body temperature. A fever, which is an elevated body temperature, leads to a physiological response that decreases the affinity of haemoglobin for oxygen. This is because higher temperatures promote the dissociation of oxygen from haemoglobin, making oxygen more readily available to tissues that are highly active and therefore in need of more oxygen.
It is also important to recognize that other variables, such as changes in blood pH or the presence of carbon dioxide, can influence haemoglobin's affinity for oxygen. However, specifically related to temperature, the presence of a fever will reduce the affinity of haemoglobin for oxygen and enhance the delivery of oxygen to the tissues.1