Final answer:
An increase in blood pH leads to an increased affinity of hemoglobin for oxygen due to the Bohr effect, where a more basic pH inhibits oxygen dissociation from hemoglobin.
Step-by-step explanation:
An increase in pH, which means a more basic or alkaline environment, inhibits oxygen dissociation from hemoglobin, therefore increasing hemoglobin's affinity for oxygen. This is known as the Bohr effect, a phenomenon describing the inverse relationship between the pH of blood and the oxygen affinity of hemoglobin.
When the pH decreases (becomes more acidic), hemoglobin's affinity for oxygen diminishes, and oxygen is more readily released to the tissues. This is important during exercise when muscle activity produces carbon dioxide, leading to a mildly acidic environment and the need for more oxygen in active tissues.