Noninvasive assessment of mental, physical and respiratory stressors on cardiovascular function

Stress is encountered in daily life from relationships with people, work obligations, and our environment. Often viewed from the realm of the social sciences, this field of study was perceived to be limited to descriptive measures, which only captured information discretely. As medicine started to investigate the biological ramifications of the stress response, it elevated the importance of stress as a precursor to several chronic diseases, which manifest both physically and mentally. As a result, many sub-areas of research have emerged to examine the relationship of stress to various systems within the human body, which include the endocrine, cardiovascular, respiratory systems. Growing understanding of the biological realities of stress will help disentangle the multiple connotations of stress. It can aid in producing better targeted medications and treatments. This thesis compared three types of stressors and sought to determine which cardiovascular parameters were most sensitive to stress. Young volunteers were subjected to mental, physical and respiratory stressors while their variability of heart rate, blood pressure and blood flow velocity were measured to examine the role of stress on the cardiovascular system. From comparisons between the rest and different stressor interventions for each subject, statistics from paired T tests show significant differences exist between each stressor and rest phase. In addition, testing of the null hypothesis against T wave amplitude, QT interval, R-P onset, frequency, beats per minute, change in blood pressure and change in blood flow velocity reveal the most sensitive cardiovascular parameters are frequency, beats per minute, blood pressure and flow velocity. These cardiovascular parameters can be used as indicators to study the course of coronary artery disease, myocardial infarction, atherosclerosis and hypertension. The present study can be improved by including measurement of glucose and stress hormones during stressor interventions to enhance our understanding of the stress response. This would aid in studying other stress-induced diseases outside the realm of the cardiovascular system.M.S.Includes bibliographical references (p. 89-91)