Date of Award

8-2020

Document Type

Campus Access Thesis

Degree Name

Master of Science (MS)

Department

Exercise and Health Science

First Advisor

Huimin Yan

Second Advisor

Sarah Camhi

Third Advisor

Tongjian You

Abstract

African Americans (AA) exhibit heightened blood pressure following aerobic exercise compared to Caucasian Americans (CA). Emerging evidence also suggests that AA exhibit impaired cardiac autonomic modulation at rest compared to CA. Despite the growing popularity of high-intensity anaerobic exercise, few studies have examined the acute effects of this form of exercise on blood pressure and cardiac autonomic recovery, or potential racial differences in these responses.

Purpose: To compare blood pressure and autonomic recovery responses to two bouts of acute maximal anaerobic exercise in young, healthy AA and CA women.

Methods: Twenty (AA= 8; CA= 12) young, healthy women without hypertension completed two consecutive bouts of maximal anaerobic exercise performed on the cycle ergometer with 30 minutes of recovery in between. Brachial and aortic blood pressures were measured at rest and 15- and 30-minutes following each exercise bout. Baroreflex sensitivity (BRS) and heart rate variability (HRV) were recorded at rest and 20-minutes following exercise. Two-way repeated measures ANOVA (race by time) was used to test for differences between AA and CA in response to exercise. Two-way site by time ANOVA was used to test differences in brachial and aortic blood pressure during recovery in all participants.

Results: Brachial mean arterial pressure and diastolic blood pressure were higher in AA women compared to CA women during recovery from exercise (p<0.05). Regardless of race, aortic blood pressure was maintained while brachial blood pressure responded to exercise in all participants (p<0.05). In a subset of participants with HRV measurements, very-low frequency and low frequency bands of HRV, which are associated with sympathovagal balance and vasomotor tone, were lower in AA compared to CA during recovery from exercise (p<0.05).

Conclusion: AA women had higher brachial blood pressure during recovery compared to their CA counterparts, which could contribute to their increased cardiovascular risk. In addition, brachial blood pressure was responsive to exercise while aortic blood pressure was maintained, suggesting short bouts of anaerobic maximal exercise may not alter aortic blood pressure in young, healthy women. Lastly, the preliminary findings from the current study supports racial differences in cardiac autonomic recovery in AA and CA.

Comments

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