The body's immune response is affected in distinctly different ways by the two widely-recognized determinants of the stress response: the controllability or uncontrollability of the stressor, and the mental effort or demand required to cope with the stress, new research shows.
"An uncontrollable stressor that lasts 15 minutes can have consequences for health because it may interfere with cytokine interleukin-6 function, which plays an essential role in activating the immune defense," said Madelon L. Peters, PhD, head of the Dutch study.
Uncontrollable stressors also produce high levels of cortisol, which suppresses immune system functioning and may have a prolonged detrimental effect for health, the researchers reported.
On the other hand, the scientists found that the mental efforts required to cope with high-level stressors produce only brief immune changes that appear to have little consequence for health.
The researchers' findings emerged from a study that involved taking repeated blood and saliva samples, blood pressure readings and electrocardiograms from 96 male students aged 18 to 28 while they performed high-effort or low-effort mathematical and other tasks under continuous noise.
Half of the students could control the intensity of the noise coming through their earphones, the others could not. Some of the tasks in the uncontrollable condition were rigged to guarantee failure.