A study of treadmill exercise protocols for Chinese males

Treadmill stress testing currently is used in screening for coronary artery disease. Maximal oxygen consumption is the best index of work capacity and maximal cardiovascular function. Clinically, there are many exercise protocols being utilized, including Bruce, Kattus, Balke, Naughton, and Chinese Air Force (CAF). The purpose of this study is to compare five of them and evaluate their reproducibility. Each of 24 volunteers performed one exercise test per week for 3 periods totalling 15 weeks. During each period, the five different protocols were performed in individually randomized order. Maximal and submaximal oxygen consumption and heart rate were determined. Statistical analysis revealed no difference in maximal oxygen consumption among the various protocols; however significant differences did exist in maximal treadmill time. Maximal exertional duration was not affected by the test periods. All of the five protocols were equally reproducible. The Chinese Air Force has adopted a treadmill protocol with a constant speed of 3.5 mph and a 5% increase in elevation every 3 min. The physiological parameters measured by this protocol include a maximal heart rate of 181 beats/min; maximal oxygen consumption of 48 ml/kg/min; and maximal exercise duration of 17 min. Bruce and Balke protocols were 13 and 24 min, respectively, in our study. The regression equation of oxygen consumption and duration was: Y (ml/kg/min) = 1.26X (min) + 26.3. The CAF protocol is a safe, reproducible, easily performed method with moderate exercise duration. We confirm its advantages and prefer to select this protocol to serve as a routine screening or clinical method for use in testing Chinese people.