The purpose of this study was to investigate the effect of submaximal physical activity (PWC170 test) on electrocardiogram (ECG) amplitude parameters in men of different ages. Materials and methods. The research involved apparently healthy men aged 20–29 (n = 27) and 40–49 (n = 27) years living in the European North of Russia. They performed a bicycle ergometer PWC170 test with incrementally increasing 3-minute loads (50, 100 and 150 W) and ECG recording in the Nehb leads. Results. A and D leads showed the most informative dynamics of ECG parameters in the subjects during the exercise test. It was mainly expressed in an increase in P wave amplitude, a decrease in T wave amplitude, a deepening of the S wave, and ST segment depression. The group of 40–49-year-old men, compared to 20–29-year-olds, was characterized by less pronounced T wave (lead D) amplitude changes at the beginning of the test, a less deep S wave (lead I), no shift in the ST segment (lead D) as well as a smaller number of parameters that showed statistically significant changes in the exercise test. ST segment (lead A) depression during the final load was twice as common in the older group of men (13 % in 20–29-year-olds and 25 % in 40–49-year-olds). Heart rate (HR) at all stages of the test, except for the last one, was lower in 40–49-year-olds; however, its more significant increase by the end of the test eliminated the statistical differences in HR at the final stage and in physical work capacity (PWC170) between the groups. The revealed differences in ECG and HR parameters may be associated with morphological changes occurring in the cardiovascular system with age, in particular, with the decrease in left ventricular function. Submaximal physical activity in men of the older age group involves a greater expenditure of myocardial reserves.
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