Date of Award

5-2021

Document Type

Campus Access Thesis

Degree Name

Master of Science (MS)

Department

Exercise and Health Science

First Advisor

Huimin Yan

Second Advisor

Azizah J. Jor'dan

Third Advisor

Kai Zou

Abstract

Aerobic exercise elicits heightened cardiovascular hemodynamic responses in Black individuals when compared to White individuals. Aortic wave reflection is a predictor of negative cardiovascular outcomes. Wave separation analysis is a novel method used to examine aortic wave reflection after exercise by decomposing the aortic pressure wave. Racial differences in anaerobic exercise responses using wave separation analysis have yet to be explored.

Purpose: To compare aortic hemodynamics after repeated bouts of maximal anaerobic cycling exercise in young Black and White women using wave separation analysis.

Methods: Twenty (Black: n=8, White: n=12) young, normotensive, healthy women completed two consecutive maximal anaerobic cycle ergometer bouts using the steep ramp test protocol with 30 minutes of recovery in between bouts. Hemodynamic measurements and brachial blood pressure were taken at rest, and 5-, 15-, and 30-minutes following each exercise bout. Forward wave, backward wave, and reflection magnitude (RM) were assessed using an automated cuff (SphygmoCor XCEL System; AtCor Medical Pty Ltd., Sydney, Australia). Systolic pressure-time integral, diastolic pressure-time integral (DPTI), and subendocardial viability ratio were also calculated. Augmentation index (AIx) was also measured. Two-way ANOVA was used to test for potential race and time differences between the groups.

Results: There was a race by time interaction for DPTI (p=0.021). DPTI, a marker for coronary perfusion, was decreased in Black women but not White women 30-minutes after an acute bout of maximal exercise, indicating lowered coronary perfusion following maximal anaerobic exercise in Black women. There were main effects of time for DPTI (p<0.001) and AIx (p=0.019). RM was greatly reduced following repeated bouts of exercise in White women but not Black women (p=0.015), indicating aortic wave reflection had returned to resting levels in Black women but not in White women following acute exercise bouts.

Conclusion: Young, seemingly healthy, normotensive Black women exhibited lowered coronary perfusion and sustained arterial wave reflection following repeated bouts of maximal anaerobic cycling exercise, compared to their White counterparts. Impaired vasodilation and greater systemic vascular resistance in Black women may contribute to these racial differences in hemodynamic responses.

Comments

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