Abstract

It is accepted to make the decision about interval physical load or functional state of the body in accordance with dynamics of heart rate (HR) during physical activity. Various parameters of electrocardiogram (ECG) allows to reveal some peculiarities of cardiac functional state and to perform a more detailed assessment of cardiac performance features, including the address of myocardial mechanical workload change. The purpose of this study was to compare the peculiarities in dynamics of HR and JT/RR ratio change as a cardiac muscle workload indicator while performing a dosed aerobic and maximal anaerobic exercise tests in normal condition and state of fatigue. Participants of the study twelve middle-distance runners performed anaerobic training session. Functional state was assessed before the training session and after 15 minutes of the end of training. The study subjects performed a Roufier exercise test (dosed exercise test) and 30-s vertical jumps test (maximal anaerobic test) and after five-minutes of the rest again performed the Roufier test. Anaerobic type of training session was created by performing running bouts of 5x200 meters, in the intensity while prevailing the anaerobic pathway of resynthesis of ATP. The intervals of rest between bouts were 2 minutes. A computerized ECG recording and analysis system “Kaunas-load” was employed for continuous registration and analysis of 12-lead of ECG. Dynamics of HR, JT interval and ratio of JT/RR was analyzed. Results obtained during the study showed the steep changes of registered indices while performing the testing exercises, and the fast recovery during the first minute after exercising. After five minutes of the jumping (a single anaerobic exercise bout) performance in dose response to cardiac stress test differs significantly – there was higher increase in HR and in ratio of intervals JT/RR, i.e. accordingly, a longer duration of cardiac mechanical work. If the fast recovery during the first minute after exercising (fast recovery phase) was characteristic feature for both registered indices, the different nature in dynamics was within the next minutes of recovery. HR dynamics during the second and third minutes of recovery has the tendency to continue decrease in registered values while there no significant recovery of JT/RR. Changes in the functional state after anaerobic type of training better reflect the cardiovascular reaction to dosed exercise test while the increased duration of mechanical work of cardiac muscle to maximal exercising may be is a characteristic individual feature which does not depend an the degree of current fatigue. A rapid decrease in HR and cardiac workload values is during the fast recovery phase while at the slow recovery phase the recovery of cardiac workload is significantly less than recovery of HR. Verf.-Referat