College of Science and Health Theses and Dissertations

Date of Award

Summer 8-21-2022

Degree Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Susan Tran, PhD

Second Advisor

Jocelyn Carter, PhD

Third Advisor

Kathy Grant, PhD


Young adulthood is a critical point of transition accompanied by a number of different stressors. Exposure to a stressor activates two systems – the hypothalamic pituitary axis (HPA) and sympathetic adrenal medullary (SAM) system. Research has primarily examined HPA axis and its corresponding stress hormone, salivary cortisol with little attention on sympathetic nervous system (SNS) markers. However, emerging research has proposed salivary alpha amylase (sAA) as a potential surrogate for SNS activity. The existing neuroendocrine research on sAA has largely focused on acute stressors and it is important to understand how sAA behaves in response to different levels of stressors – both proximal and distal stressors. This study sets out to examine the impact of daily hassles, life stressors, and chronic medical conditions on sAA in young adults. Exploratory analyses were conducted to understand how life stressors and chronic medical conditions influence diurnal patterns of sAA. Longitudinal data were collected from 83 young adults (63.9% female) between the ages of 18-24 at a large Midwestern University. Results found a significant relationship between the number of life stressors and average sAA output where average sAA output increased as the number of life stressors increased. Diurnal patterns of sAA demonstrated significant differences in high life stressors groups compared to the life stressors group 30 minutes after waking and in the evening. Daily hassles and CMCs did not significantly influence sAA output. Results suggest distal stressors impact SAM sensitivity. Future longitudinal research is warranted to further substantiate sAA as a measure of SNS activity and better understand how different types of stressors impact SNS activity.

SLP Collection


Included in

Psychology Commons