Effect of Acute Blood Pressure Reduction on Oxygen Kinetic Values in Hypertensive Cases

Exercise tests performed at the submaximal level are valuable in the evaluation of complaints during daily activities. Fatigue and shortness of breath are among the common complaints of most hypertensive patients during daily activities. We aimed to evaluate this the effects of blood pressure control on oxygen kinetic values. Twenty-eight patients with uncontrolled blood pressure were included. Patients performed exercise tests with modified Bruce protocol for 6 minutes upon which blood pressures rose to 183±13mmHg systolic and 94±9 mmHg diastolic levels. Oral captopril administration reduced these readings to 133±8 mmHg and 84±5 mmHg, respectively. Variability in oxygen kinetic values (oxygen deficit and mean response time) between both tests was investigated. Oxygen deficit values and the mean response time measured during the exercise tests, which the patients performed at a constant velocity and when their blood pressures were high, were found to be 511±138 mililiters (ml) and 44±12 seconds (sec), respectively. During the second exercise tests performed after blood pressure reduction with captopril, oxygen deficit and mean response time to exercise were 397±126 ml and 36±9 sec respectively. The difference was statistically significant (p=0.0001, p=0.001). Hence, there is a significant improvement in oxygen kinetic values in the early period with normalization of blood pressure. This is in support of the concept that the heart adapts to exercise more easily and performs the same amount of work with less energy and this underlines the importance of blood pressure control.