Summary
Highlights
Researchers assessed perceived stress, social networks, and external stressors in individuals and exposed them to the common cold. The most prominent predictor of getting sick was the individual's self-reported perceived level of stress, highlighting the subjective experience of stress as crucial for immune system impact.
Stress initiates a cascade of neurotransmitter and hormonal release, leading to the secretion of cortisol and epinephrine. These chemicals influence the number of immune cells produced, indicating that stress can significantly affect the immune system.
The immune system involves antigens (foreign substances), antibodies (proteins that bind to antigens), and immune cells (like natural killer cells and cytotoxic T cells) that destroy foreign substances. The immune system protects against disease, inspects for dangerous mutations, and cleans up cellular debris.
Natural immunity is the immediate, non-specific first line of defense against antigens, like the inflammatory response to a cut. Acquired immunity is more complex, recognizing specific antigens after prior exposure, leading to a targeted response, as seen with vaccines.
Sustained physiological effects of stress weaken both natural and acquired immunity, leading to immunosuppression and increased susceptibility to disease due to the body's reduced ability to fight antigens or damaged cells.
Animal studies using various stressors have shown reductions in immune response, immune cell numbers, and overall immune function. Human studies on naturally occurring stressors like exams or caregiving roles have also demonstrated decreased immune system function.
A 1995 experiment compared Alzheimer's caregivers (high stress) to a control group. Caregivers had significantly fewer immune variables in their blood and took longer for puncture wounds to heal, directly linking stress to diminished immune function and health outcomes.