# Transcript

NARRATOR
The fight-or-flight response is a body’s adaptive response to acutely stressful situations, both real and imagined. Acute stress causes rapid changes to occur in most body systems. There are changes to the cardiovascular systems, including increases in heart rate and contractility in heart muscle, as well as changes in the perfusion of blood through the organs of the body. There are changes in metabolism to increase the blood levels of glucose, fatty acids and amino acids. There are cognitive changes, including alterations in perception and memory. There are changes in pain perception, including stress-induced analgesia; or in other words, pain relief. There are changes to the immune system, including a short-term enhancement in its activity. Finally, there are decreases in reproductive hormone production. Overall, the response to acute stress is to prepare the body for action. This is achieved by ensuring resources are preferentially delivered to those systems needed for rapid action.