Date of Award

11-15-2006

Document Type

Thesis

Degree Name

Medical Doctor (MD)

First Advisor

David Silverman

Abstract

The purpose of this study was to determine the degree to which noninvasive measurement of blood pressure (BP) taken after discontinuation of weightlifting underestimates the peak systolic BP attained during lifting; abrupt changes in BP during such acute resistive challenges may be missed by intermittent BP measurements. In this study, 11 healthy volunteers aged 21 to 32 underwent noninvasive monitoring while performing leg thrusts to 100% of their body weight. With the subject in lifting position, baseline measurements of heart rate (HR) and BP (via automated BP cuff over a brachial artery) were obtained; ultrasonic transducers were placed over both brachial arteries. The automated cuff was removed, and manual BP cuffs were placed over both brachial arteries and inflated to 50 and 100mmHg above the baseline systolic BP. Once loss of ultrasound signal was confirmed, subjects began lifting until fatigued. If there was breakthrough by ultrasonic signal, the cuff was inflated an additional 100mmHg; the subject continued lifting until breakthrough was again detected. The peak cuff inflation pressure at which breakthrough occurred was recorded. Immediately after fatigue, an automated BP was obtained. The peak changes during lifting were compared to those of the post-lifting measurement. Data were expressed as mean ±SD; interphase differences were assessed with paired t-test. Systolic BP increased from a baseline mean of 117±11mmHg to 272±26mmHg during lifting (p<0.001) and returned to 133±11mmHg after lifting (p<0.001). HR was 67±7 beats/min at baseline and increased to 121±9 beats/min during lifting (p<0.001). The data indicate that during resistive challenges such as weightlifting, there are marked changes in BP which rapidly abate once the challenge is discontinued. This may have important implications during exercise e.g. weight lifting and in acute care settings. Monitoring the pulse distal to an occlusive cuff constitutes a simple, noninvasive method to document the changes.

Comments

This thesis is restricted to Yale network users only. This thesis is permanently embargoed from public release.

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