Cohen
- Natural experiment were 349pps answered questionnaires and were given stress scores. They were then exposed to a low dose of the common cold virus through a nasal spray. 82% of participants developed a cold and the chances of doing so were seen to be significantly correlated with stress scores.
- The higher the stress score the more likely to become infected – reduced effectiveness of the immune system
Keicolt-Glazer
- 75 medical students aged 23, both males and females had blood samples taken one month before exams and again during. NK cells were significantly reduced during exams showing lower immune systems due to higher stress levels.
Evans
- Stress improves the immune system for a short period of time