The effect of Stress on the Defence system

Stress is the body’s physiological, emotional, behavioural & cognitive response to all types of environmental threats & demands. Many times, stress is used in place of anxiety, pressure & strain.

The body tries to stay focused, & energetic and the defence system gets activated into an intense autonomic process of fight or flight reaction in case of real or imaginary danger-induced stress.

Keeping the defence system in panic mode due to constant stress brings unnecessary harm to physical & mental health.

How does the body respond to stress?

Stress incorporates a variety of physiological and psychological transformations.

1. Evaluation & recognition of stress

2. Coping resource availability is checked

3. The body gets prepared for confrontation or avoidance

4. Activation of the sympathetic nervous system & adrenaline & noradrenaline production hormones into the bloodstream

5. Blood pressure increases as the heart & respiratory system start accelerating fast

6. The body starts circulating oxygen-rich blood to the core which is the brain & large muscles instead of the extremities

7. There is more acute hearing, muscle tension, eye dilation, sweat gland activation & paleness of skin

8. Impairment of concentration & focus occurs including a negative effect on short-term memory & decision-making ability

9. There is an increase in anxiety, dull mood, fearfulness, irritability, restlessness & escapism

Effect of stress on the defence mechanism

Hypothalamic-pituitary-adrenal (HPA) axis & the sympathetic nervous system (SNS) are the major pathways involved in building a defence system. Increased stress exposure enhances the susceptibility to inflammatory disorders, infectious diseases & subnormal immunity.

The innate immune system & adaptive immune system are compromised by a stress-induced defence system decline.

Epithelial Surfaces

Stress affects the protective mechanism of mucous membranes & protein-specific biological actions.

Macrophages

Cytokine production surges as stress raises, leading to an increase in acute-phase reactants & induction of hepatic synthesis via cytokines. Substance P causes stress-induced changes in cytokine levels & macrophage responses.

NK Cells

Chronic stress impairs NK responsiveness to cytokines.

T lymphocytes

Stress decreases lymphocyte proliferative ability in response to mitogens, lectins, & to T-cell receptor activation. Simultaneously reduce the % of total T lymphocytes & Th lymphocytes.

Chemotaxis

Prolonged stress reduces chemotaxis response, the protective role of chemotactic agents & increases additional pathological parameter variation risk.

Humoral Immunity

Stress decreases antibody response & inhibits cytokine synthesis leading to putting off the balance of the Th1/Th2 cytokine network.

Along with endocrine changes, lifestyle imbalances like alteration of alcohol consumption, cigarette smoking, physical activity, and sleep deprivation hampers the humoral immune response. 

Conclusion

Brief acute stress has an exhilarating effect on immunity but, enduring stress decrease the body’s self-protection response to psychological challenges. Proper counselling & medical support may soothe the harmful effects of chronic stress, helping persistent stressed individuals to maintain the strength of their defence systems.