Stress is thought to cause health issues. For example the release of Adrenaline and Cortisol restrict blood vessels and increase heart rate, and this could lead to cardiovascular problems. Also Cortisol reduces the immune system in order to help Fight or Flight, however over time this could lead to an inability to fight of infection.
AIM – To test the link between acute stress and proficiency of the immune system.
PROCEDURE – Took blood tests of Medical students before and after exams to measure NK blood cell activity within the students. This would show the effectiveness of their immune systems.
FINDINGS – The number of NK cells, and therefore immune system activity, was a lot lower before the stressful exam period than after.
CONCLUSION – Acute stress can cause lower immunity to infection.
EVALUATION – The students might not be a representative sample of the whole population.
AIM – To test a link between Chronic stress and the speed of healing
PROCEDURE – Blistered arms of unhappy married couples with highly hostile relationships (high chronic stress levels) and those of happy couples.
FINDINGS – The blisters on the arms of happy couples healed 60% faster than those in unhappy relationships
CONCLUSION – Chronic stress can significantly reduce the body’s ability to heal
Evaluation of Research
Other Research – a meta-analysis of 293 studies by Segerstrom and Miller found that acute stress actually helps the immune system, helping the body prepare for infection, however chronic stress is still harmful.
Difficult to establish a causal link – This is because:
1) Health is affected by many factors
2) Health tends to be slow to change, so it is hard to show that the change is due to stress
3) Showing a link between long-term stress and health is impractical, so most research is done on acute, short-term stress
Individual Differences – People respond differently to stress, as do their immune system. For example elderly people’s immune system are more affected by stress than younger people.