A Comparison of Myocardial Oxygen Consumption during Three Modes of Sub-maximal Exercise Testing among Patients with Asthma

Abstract

Aim: Every individual would benefit from a well planned programme of exercise, asthmatics inclusive. The aim of this study is to compare the myocardial oxygen consumption of three exercise protocols in asthmatics Methods: Forty eight consecutive asthmatics were recruited between December 2005 and December 2006; each asthmatic performed the 3 exercise protocols (Cycle ergometer, step test and free running) in random order within a week. The systolic blood pressure (SBP) and heart rate (HR) were measured pre and post exercise. Rate pressure product (RPP) was used as a measure of myocardial oxygen consumption Results: The mean age of the patients was 24 .1±4.97 with equal number of females and males. There was no significant difference in HR, SBP and RPP, among the 3 exercise protocols at pre exercise phase. The post exercise RPP means results were; 21679.2±2741.3, 21993.3±3636.2, 20205.8±2922.4 free running, step test, cycle ergometer respectively. There was significant difference in the post exercise RPP (F=4.479 p=0.013) of the 3 exercise protocols with step test having the highest myocardial oxygen consumption. RPP in step test was significantly higher than that of free running and cycle ergometer (p 0.05). Conclusion: Step test was found to increase myocardial oxygen consumption more than free running and cycle ergometer