Psychophysiological effects of stress in diabetic patients, ischaemic heart patients and healthy subjects

This thesis is concerned with the relationships between physiological changes and subjective and behavioural responses to stress. The effects of noise stress were examined under laboratory conditions, and retrospective studies of stress induced by life events were also carried out.\ud \ud Changes in blood glucose levels were of particular significance under stressful conditions and interesting relationships were found between changes in blood glucose levels and performance at experimental tasks under stressful conditions. Performance and the experience of stress were shown to be affected by the experimental manipulations of blood glucose levels.\ud \ud The effects of stressful conditions on diabetic subjects with impaired control of blood glucose levels were of particular interest. The poor control of blood glucose levels in the 'high glucose diabetics' was exaggerated when working under noise stress. Studies of life events demonstrated that diabetic subjects' experience of life events was associated with physiological disturbance of diabetic control. Diabetics' subjective experiences of stressful conditions were also examined and compared with the experiences of control subjects.\ud \ud Previous research showed considerable evidence to suggest that stress was a promoting factor in ischaemic heart disease (IHD). Subjects with IHD and controls were included in the present research. Experiments similar to those with diabetic subjects were carried out. The IHD subjects had enhanced physiological responses to noise stress which were associated with significantly low levels of reported stress. Subjective experiences of stress were further examined with investigations of the degree of stress associated with life events by Myocardial infarction patients.\ud \ud Differences in subjective experience of stress by patient groups and their controls were discussed in relation to the concept of alexithymia.\ud \ud Experiments with healthy subjects were carried out in order to examine the mechanisms involved in the relationships found between glucose, performance and the perception and experience of stress. The effects of glucose preloading were shown to be primarily of physiological rather than of psychological origin, and a vagal-insulin model was proposed to account for the relationship between glucose preloading and performance efficiency. Experimenter effects were examined in the studies of healthy subjects and the implications of such effects discussed in relation to the results of the experiments with hospital subjects in this work and with reference to other psychophysiological research.\ud \ud The experimental findings were evaluated and suggestions made for further research. In particular research directed towards the possibility of developing a more flexible, individual approach to diabetic management, taking account of unavoidable sources of stress, was outlined