| Keywords |
Cardiovascular response ; Aerobic exercise ; Hypertension ; Cardiac output |
| Abstract |
The purpose of this study was to investigate physiologic response during dynamic exercise in the people with normotension, prehypertension, and hypertension. Thirty males (12 normotensive, 9 prehypertensive, and 9 hypertensives) were recruited in this study. To determine relative exercise intensity, all subjects completed maximal cycling exercise test and then performed two submaximal testing at the intensity of 40% and 60% VO2max. Subjects were instrumented to measure the cardiovascular responses by non-invasive method through the experiment. Heart rate (HR), stroke volume (SV), and cardiac output (CO) were measured by Physio Flow and blood pressure was measured by mercury sphygmomanometer from the brachial artery. The results indicate that excessive response in blood pressure was found in the both prehypertensives and hypertensives with increasing exercise intensiy compared to normotensives, and the hypertensives had a significantly higher blood pressure compared to prehypertensives. Both prehypertension and hypertension had significantly higher CO during dynamic exercise compared to normotension. The CO response also tended to be higher in hypertensives compared to the prehypertensives. Total vascular conductances (TVC) were significantly increased in three groups as the exercise intensity increased, but there were no significant differences between groups. Thus, the excessive pressor response in both prehypertension and hypertension during dynamic exercise is mediated by an increase in CO despite little change in TVC. This study suggests that the strategies to treat excessive cardiac output response may prevent an exaggerated blood pressure response during dynamic exercise in both prehypertension and hypertension. |