Final answer:
The exhaustion stage of the General Adaptation Syndrome leads to a temporary reduction in immune system functioning and is associated with long-term stress.
Step-by-step explanation:
The exhaustion stage of the General Adaptation Syndrome is characterized by a reduction in immune system functioning that will be temporary if the stress is over quickly. This stage of exhaustion occurs if the stress continues for a longer term, leading to symptoms such as depression, the suppression of the immune response, severe fatigue, or even a fatal heart attack. The hormones of the adrenal cortex, particularly cortisol released via the HPA axis, mediate these symptoms.