stress, hypertension, high blood pressure, cardiovascular response, military, combat, deployment
PURPOSE: Hypertension (HTN) affects one in every three adults in the United States. Often associated with the older population, this silent killer has emerged in an unsuspecting group, young military soldiers. With the rapid succession of multiple deployments, long intervals between blood pressure (BP) assessments, and the absence of cardiovascular (CV) measures during the pre and post deployment health screenings; soldiers may be at higher risk for HTN than their civilian counterparts of the same age. The purpose of this study was to explore real-time continuous CV measures of soldiers before, during, and after exposure to a simulated combat stressor as well as to assess which personal characteristics played a significant role. METHODS: Applying the Allostasis/Allostatic Load theoretical framework, a repeated measure quasi-experimental design was used to compare the CV measures of two groups: one exposed to a physical combat stressor (experimental) and the other exposed to a psychological combat stressor (control). A convenience sample of 60 college Army Reserve Officer Training Corps cadets were fitted with Tiba Medical Ambulo 2400 ambulatory BP monitors for 48 continuous hours. Several CV indices were analyzed using one-way Analysis of Variance (ANOVA), paired t-test, and independent sample t-test. Four instruments (Participant Information Sheet, State-Trait Anxiety Inventory, Paintball Perceived Stress Questionnaire, and Army Physical Fitness Test) were used to assess which characteristics played the most significant role in the CV response. RESULTS: Demographic characteristics between the two 30-cadet groups were not statistically different, with the exception of deployment history (experimental = 4, control= 0). Hours after the stress exposure, subjects in the experimental group had a higher mean awake systolic blood pressure (SBP) when compared to the control group (113.76 mm Hg vs 102.98 mm Hg, p= 009). When assessing pre and post stressor morning BP surge and evening BP decline, the control group showed the biggest change. Significant bivariate correlations (p > .05) found that: Females consistently had higher pulse rates (PR) throughout each of the phases. Age positively correlated with elevated BP during the stressor, and increased morning BP surge post stressor. African Americans had higher sleep BPs pre stressor, and decreased SBP recovery post stressor; Hispanics had higher PRs during and after the stressor. Waist circumference positively correlated with elevated BP morning surge pre stressor but, body mass index (BMI) positively correlated with elevated BP morning surge post stressor as well as elevated BP during the stressor. Family history of HTN played no significant role; however, deployment history correlated with mean awake SBP post stressor. Trait anxiety scores negatively correlated with SBP recovery while state anxiety scores positively correlated with post stressor awake mean arterial pressure and evening SPB decline. Perceived stress during the stressor negatively correlated with post stressor SBP morning surge with females reporting higher anxiety and stress. Finally, Army Physical Fitness (APFT) total scores as well as APFT run scores negatively correlated with pre and post stressor sleep PRs. DISCUSSION/IMPLICATIONS: Age, female gender, African American descent, Hispanic ethnicity, waist circumference, BMI, previous deployment history, level of fitness and the psychological stress state during and after a stressor played significant roles in soldiers' CV response. SBP was the most dynamic and informative of the CV indices and a psychological stressor was comparable to a physical stressor when observing the residual effect of stress. If a combat exercise was enough of a stressor to produce residual CV effects that lasted well into following morning, the residual effect of a lengthy strenuous deployment may be alarming. This study not only provided a snapshot of the CV health of incoming young soldiers, but also provided evidence to support policy change regarding the implementation of regular CV health assessments before and after deployment.
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Sole, Mary Lou
Doctor of Philosophy (Ph.D.)
College of Nursing
Length of Campus-only Access
Doctoral Dissertation (Open Access)
Gantt, MeLisa, "The Effect Of Combat Exercises On Cardiovascular Response: An Exploratory Study" (2010). Electronic Theses and Dissertations. 4324.