Which type of stress is associated with upregulation of natural immunity?

• A. Chronic stress
• B. Neither
• C. Both chronic and acute stress
• D. Acute stress

Answer: (D)

Acute stress can transiently boost the innate, or natural, immune response. When a stressor is short-lived, the body activates the sympathetic nervous system and releases catecholamines that rapidly mobilize innate immune cells—such as natural killer (NK) cells and neutrophils—into circulation. This quick mobilization quickens the first line of defense, aligning with upregulation of natural immunity.

In contrast, chronic stress tends to weaken overall immune function over time, with reduced activity of certain immune cells and dysregulated inflammatory responses, rather than sustaining a heightened innate response. This is why the acute pattern best fits the idea of upregulating natural immunity.

So the correct idea is that acute stress, not chronic stress, is associated with an upregulation of the innate immune system.