Doctoral Dissertations

Date of Award

8-1995

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Education

Major Professor

David R. Bassett Jr.

Committee Members

Roland Bagby, Dewey Bunting

Abstract

Despite the fact that swimming is widely recommended for the prevention and treatment of hypertension, no study has examined the potential efficacy of regular swimming exercise for lowering blood pressure in hypertensive humans. To test the hypothesis that regular swimming exercise lowers resting blood pressure, previously-sedentary individuals with stage I to II hypertension were divided into a swim training (n=12) and non-exercising control group (n=6). The training group swam at 60% of maximal oxygen uptake for 45 minutes per day 3 days/week for 10 weeks whereas the control group remained sedentary. In the swim training group, systolic blood pressure fell from 150±5 to 144±4 mmHg (p<0.05). Diastolic and mean arterial blood pressure did not change significantly. Resting heart rate decreased from 81±4 to 71±3 bpm (p<0.05). Significant reductions (p<0.05) were observed in ratings of perceived exertion, heart rate, and blood lactate concentrations during fixed submaximal exercise on an arm cycle ergometer. Although caloric and macronutrient intake estimated from the dietary records stayed constant before and after training, body mass and body fat percentage showed no statistically significant changes. No significant changes were observed in plasma epinephrine and norepinephrine concentrations, casual forearm vascular resistance, plasma volume and blood volume. Fasting serum glucose and insulin concentrations, and glucose/insulin ratio were unchanged after training. There was a significant increase (p<0.05) in vigor/activity on the Profile of Mood States questionnaire. Although total and LDL-cholesterol decreased by 14.4 and 10.1 mg/dl, respectively, the relatively large change did not reach significance. There were no significant changes in any of these variables in the control group. Blood pressure changes were not associated with changes in body mass, body fat, waist-to-hip ratio, vascular resistance, plasma catecholamines, plasma volume, serum cholesterol, fasting glucose and insulin. It was concluded that swim training elicited a significant reduction in arterial blood pressure in individuals with hypertension although the magnitude of the blood pressure reduction was smaller than that typically observed in land-based exercise training.

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