CARDIORESPIRATORY RESPONSE

Cardiorespiratory Response Under Combined Psychological And Exercise Stress



CHAPTER 1: INTRODUCTION

Problem Statement

The effects of combined physical and psychological stress on cardiovascular and respiratory responses will be examined.

Rationale

The link between stress and cardiovascular disease has received much experimental psychophysiological study during the past decade (Blascovich and Katkin, 1993; Matthews et al., 1986). The usual experimental paradigm employed in such research involves the challenge of a physical (e.g., cold pressor, exercise) or psychological (e.g., mental arithl Corresponding author. metic, signal detection) stressor presented to subjects while physiological measurements will be made. While one or more types of stressors (i.e., physical or psychological) have been used singly in some studies, few studies have examined physiological responses to combinations of stressors. Investigations of the interactive effects of stressors on physiological response may prove enlightening because individuals will be often exposed in everyday life to concurrent combinations of stressors, rather than discrete isolated stressors. (see figure 01 in appendix)

Aims and Objectives

Cardiovascular responses during the combination of exercise and mental arithmetic stress will be greater than those during either stressor alone, indicating that exercise did not mask the increases in cardiovascular performance evoked by psychological stress.

respiratory responses to the combined stressor will be greater than those during isolated mental arithmetic, but less than those during isolated exercise.

Significance

The results indicate that physical and psychological stress exert a synergistic impact on cardiac performance, but not necessarily on respiratory performance. The results will be consistent with the notion that the cardiovascular response to acute psychological stress exceeds concurrent metabolic demands.

Hypothesis

concurrent physical and psychological stressors may induce a response no greater than that induced by the most demanding stressor (the masking hypothesis);

Concurrent physical and psychological stressors may induce a response that is greater than that induced independently by either stressor alone (the synergistic hypothesis).

Theoretical Frame work

Assuming that moderate aerobic exercise by itself is beneficial and produces a stronger physiological response than that produced by psychological stress, the masking hypothesis implies that exercise during psychological stress may be beneficial. This hypothesis also suggests that ongoing metabolic demands will be the predominant influence on cardiovascular responses to stress. In contrast, the synergistic hypothesis implies that the challenge of combined exercise and psychological stress may not be beneficial in alleviating cardiovascular responses to psychological stress. This hypothesis also suggests that ongoing metabolic demands will be not the sole or predominant influence on cardiovascular responses to stress, and that such responses may exceed concurrent metabolic requirements. Thus, despite the value of aerobic exercise for physicaf fitness, the synergistic hypothesis suggests that exercise during the concurrent experience of psychological stress may be ineffective in reducing psychologically mediated cardiovascular responses, and may actually increase pathophysiological risk. Although these hypotheses have not been tested explicitly, several studies of cardiovascular responses to biofeedback during aerobic exercise suggest that cardiovascular responses which will be ostensibly due to exercise can be attenuated by psychological processes (Goldstein et al., 1977; Lo and Johnson, 1984; Perske and Engel, 1980). In a related vein, Schwartz et ...