Which of the following is NOT a physiologic change associated with the immediate stress response?

The immediate stress response, often referred to as the "fight or flight" response, triggers a series of physiological changes designed to prepare the body for action. This includes the release of stress hormones such as adrenaline, which facilitate heightened awareness and physical capability.

Decreased pain perception is one of the key aspects of this response, allowing an individual to endure injury or discomfort while focusing on immediate survival needs. This analgesic effect is a protective mechanism, enabling better performance during stressful situations without being hindered by pain.

In contrast, increased heart rate, diversion of blood flow to major organs, and increased respiratory rate are all integral components of the immediate stress response. These changes ensure that the body can deliver oxygen and nutrients more efficiently to essential organs and muscles, supporting rapid movement and heightened alertness. Specifically, an increased heart rate pumps blood faster, while an increased respiratory rate enhances oxygen intake, both of which are critical during times of stress.

Therefore, the correct answer highlights the unique nature of pain perception in the context of stress, distinguishing it from other physiological changes that occur in response to stressors.