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The effects of stress on the immune system
Short term stressors- examination stress
Kiecolt-glaser et al. (1984) she took blood samples from medical students a
month before exams and during examination period. She looked at their NK
cell activity and found that in the blood samples taken during examination
period the NK cell activity was significantly reduced than in the blood samples
taken a month before the exams when the students were experiencing low
levels of stress. This shows us that short term stress has an effect on our
immune system and makes us more vulnerable to illnesses.
Marucha et al- inflicted a punch biopsy in the mouths of students during
summer holidays and 3 days before an exam. He found that the wounds given
3 days before exams took 40% longer to heal than the wounds given during
the summer holidays.
Ongoing stressors- relationship stress.
Kiecolt-glaser et al looked at the impact of interpersonal conflict on wound
healing; she found that blister wounds on arms of married couples took longer
to heal after a discussion which was conflicting rather than supportive.
Further, kiecolt-glaser et al compared women separated from their partners
with matched married controls and found poorer immune system functioning in
women who had separated in the last year.
Stress can sometimes enhance the immune system:
Evans et al looked at the activity of an antibody- slgA- which helps protect
against infections. They arranged for students to give talks to other students
(mild but acute stress) these students showed an increase in slgA activity
whereas levels of slgA decreased during examination periods which stretched
over several weeks. So Evans et al propose that stress may have two effects
on the immune system: up regulations (increased efficiency) for acute stress
and down regulation for chronic stress.
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Meta analysis done by segerstorm and miller.
A meta analysis of 293 studies conducted over the past 30 years found:
1. short term, acute stressors enhance the immune system/ boost the immune
2. Long term chronic stressors led to suppression of the immune system.
3. The longer the stress the more the immune system shifted from potentially
adaptive changes to potentially detrimental changes.…read more