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Document Type

Thesis - University Access Only

Award Date

2003

Degree Name

Master of Science (MS)

Department / School

Health, Physical Education, and Recreation

First Advisor

Matthew Vukovich

Abstract

The purpose of this study was to determine the effects of a caffeine/herbal ephedra supplement on cardiovascular measurements during exercise. Ten caffeine-naive subjects (5 women and 5 men) were studied at rest, during exercise, and during recovery after the ingestion of either a placebo (PL) or 150mg of caffeine/20mg ephedrine (C+E). After the consumption of placebo or caffeine/ephedrine, subjects rested for 60 minutes. Measurements of heart rate, blood pressure, cardiac output and expired gas samples were made before and after 30 and 60 minute after supplementation. Subjects then began exercising at 60% VO2 max on a cycle ergometer. Measurements were obtained at 10, 30, and 60 minutes of exercise. Following exercise, measurements were obtained at 15, 45, 60 minutes of recovery. HR was higher (P<0.05) at 60 min rest in C+E compared to PL and remained significantly higher at 30 and 60 min of exercise and 15, 45, and 60 min of recovery. Stroke volume was lower (P><0.05) at 45 min of exercise and 15, 45, and 60 min of recovery. There was no difference in cardiac output between treatments. Systolic blood pressure (SBP) was not different at rest between treatments. SBP was higher (P><0.05) at 30 and 60 min of rest in C+E compared to PL. There was no difference in SBP during exercise and recovery between treatments. There was no difference in diastolic blood pressure between treatments. Mean arterial pressure (MAP) was higher (P><0.05) in C+E at 60 min of rest and 45 and 60 minutes of recovery. MAP was not different during exercise><0.05) at 60 min rest in C+E compared to PL and remained significantly higher at 30 and 60 min of exercise and 15, 45, and 60 min of recovery. Stroke volume was lower (P<0.05) at 45 min of exercise and 15, 45, and 60 min of recovery. There was no difference in cardiac output between treatments. Systolic blood pressure (SBP) was not different at rest between treatments. SBP was higher (P<0.05) at 30 and 60 min of rest in C+E compared to PL. ><0.05) at 30 and 60 min of rest in C+E compared to PL. There was no difference in SBP during exercise and recovery between treatments. There was no difference in diastolic blood pressure between treatments. Mean arterial pressure (MAP) was higher (P<0.05) in C+E at 60 min of rest and 45 and 60 minutes of recovery. MAP was not different during exercise ><0.05) in C+E at 60 min of rest and 45 and 60 minutes of recovery. MAP was not different during exercise between treatments. Rate pressure product was higher (P<0.05) in C+E compared to PL at 60 min of rest, 60 min of exercise and 15, 45, and 60 min of recovery. These findings indicate that C+E prior to exercise will alter the cardiovascular system by increase in heart rate prior, during, and after exercise and SBP before exercise. The higher rate pressure product prior to and after exercise indicates greater energy demands of the heart when individuals consume C+E.><0.05) in C+E compared to PL at 60 min of rest, 60 min of exercise and 15, 45, and 60 min of recovery. These findings indicate that C+E prior to exercise will alter the cardiovascular system by increase in heart rate prior, during, and after exercise and SBP before exercise. The higher rate pressure product prior to and after exercise indicates greater energy demands of the heart when individuals consume C+E.

Library of Congress Subject Headings

Caffeine -- Physiological effect
Ephedrine -- Physiological effect
Cycling -- Physiological aspects

Format

application/pdf

Publisher

South Dakota State University

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