There are 2 main theories of why stress increases the risk of cardiovascular disorders; direct mechanical effects and energy mobilisation. There is evidence for and against these theories. Rosenman studied 32000 men and split them into 2 groups; type A and type B. The men in type A were competitive, active and irritant whereas participants in type B were calmer. Rosenman split them into groups by studying the participant’s behaviour during an interview, the interviewer would purposely interrupt them to see how the participant reacted. 8. 5 years later, 257 of these men had developed CHD.
Findings showed that 70% of these men were type A even when other factors were taken into account such as smoking and their diet. When these participants were investigated further, it was found that the main factor was hostility. This study supports that stress can cause cardiovascular disorders, and factors in a person’s personality can increase the chance of a disorder. This study shows the link between cardiovascular disorders and certain personality types. It has helped give advice on how to reduce the risks cardiovascular disorders by altering lifestyles.
Also it is supported by other large longitudinal studies that found the same results such as Haynes, although there are disadvantages. The participants are an unfair sample as they do not represent a variety of people, they are all men from the same area and of similar age. This makes the study less valid as it does not relate to everyone. Also it doesn’t take into account that some people do not have all characteristics of type A but do have some, it is unclear how vulnerable these people are to cardiovascular disorders. Many studies have failed to find a link between type A and cardiovascular disorders as the characteristics are so general.
This makes the study less valid, as there is support for contrasting theories. Rosenman’s study is non-experimental, therefore not all variables are controlled. This means that the cause for CHD cannot be established as there may be other factors. The participants may have changed their lifestyle after the study if they realised they were in danger, this would have reduced the amount of people that formed CHD, therefore the results are not accurate . Krantz also did a study to see if cardiovascular disorders are linked to stress.
39 participants and 12 control participants were studied while doing 3 mental tasks, each designed to cause stress. While doing tasks, their blood pressure and contraction of blood vessels was measured. Findings showed that participants with the highest blood pressure also had the highest contraction of vessels whereas some had little contraction of either. This study shows that there is a direct link between stressful cognitive tasks and psychological activity. It also shows that individual differences need to be taken into account, as participants did not all respond the same. Similar to Rosenman’s study, there are also disadvantages.
There are ethical issues as the participant was purposely put under stress. It does not take into account that some people already have a high blood pressure due to other factors or other stress. Also the participant’s blood pressure was not taken when they were not stressed therefore it is not known what their normal blood pressure was. Williams did a study to see if anger is linked to heart disease. 1000 participants were asked to rate their anger in a series of questions. 6 years later, the participant’s health was examined. 256 of the participants had experienced a heart attack, those who had scored high on the anger scale were 2.69 more likely to have a heart attack.
This study supports the link between anger and cardiovascular disorders. Although this study does have disadvantages. The participants were asked to rate their anger, the definition of angry could vary from person to person and therefore is not a very accurate way of measuring anger. Also participants may have rated their anger lower due to demand characteristic, and wanting to impress Williams. There could have been other factors contributing to the cause of the heart attack, for example it does not take into account if the participant is obese, drinks or smokes.
Russek and Zohman compared participants with stressful medical jobs (GPs) and participants with less stressful jobs (dermatologists). It was found that 11. 9% of the GPs had suffered from heart disease whereas only 3. 2% of dermatologists had. This supports the link between stress and heart disease. This study assumes that GPs have a more stressful job although it could be seen as less stressful as they have more social stimulation. Also it is not clear whether the link is direct or indirect as the GPs may be more likely to smoke or drink due to the stress, rather than the stressor itself doing the actual damage.
This study also has an unfair sample as all participants are doctors, they do not represent a variety of people as are all in a similar profession and probably of a similar intelligence. This study has emphasised the importance of support at work, as it can be stressful and have negative effects. Ultimately, all of the studies above show a link between stress and cardiovascular disorders, although it is hard to specify whether the link is direct or indirect. It is also hard to specify what the main factor is, hostility, anger or a person’s profession.