Fear Free Veterinary Certification 2026 – 400 Free Practice Questions to Pass the Exam

The immediate stress response, often referred to as the "fight or flight" reaction, is characterized by rapid physiological changes that are initiated by the sympathetic nervous system. When an animal perceives a threat or stressor, this system triggers a cascade of bodily responses that prepare the individual to either confront or escape the situation.

These responses include increased heart rate, heightened blood pressure, rapid breathing, and the release of stress hormones such as adrenaline. These changes occur almost instantaneously and are designed to enhance the animal's ability to respond to acute danger.

Other types of stress responses, such as chronic or delayed stress responses, involve more prolonged or gradual changes and do not provide the immediate physiological reactions characteristic of the sympathetic nervous system. Therefore, the immediate stress response is the most accurate descriptor of quick physiological changes that occur in the face of immediate threats.