Purpose: The aim of this study was to determine the influence of 30min. of moderate and heavy intensity aerobic exercise to heart rate during interval incremental exercise. Methods: Eight healthy males (mean SD 23 1yr; 76 4,8 kg; 178 6,6 cm) were tested 3 times. They performed incremental veloergometer exercise test until subjective exhaustion. Pedalling rate was maintained constant at 70 rpm. Test began with 4 min. of cycling at 25 W. Then the workload was increased by 25 W and maintained for 3 min. until participant ,s heart rate (HR) reached 90 % of HRmax (220 - age, year). Between workloads the participants rested for 4 min. Two times exercise was preceded by 30 min. of moderate (equal to lactate threshold), heavy intensity (50 W heavier than lactate threshold) or no warm-up. Capillary blood samples were drawn from finger to measure lactate concentration at rest and 5, 10, 20, 30, min. during work. HR was registered before exercise and every 5 min. during work. Also HR was recorded every 5 s. during interval incremental veloergometer test. The heart rate data were modelled using single exponential models, which included amplitudes, time constants and asimptotics values. Results: Heart rate was more elevated during heavy warm-up compared to the moderate (3 min. – 140 13,7; 13 min. – 158 16,1; 23 min. – 164 13,6; 26 min. - 167 13,7 and 3 min. – 128 8,7; 13 min. – 134 11,2; 23 min. – 140 11,2; 26 min. – 142 10,9 beats/min. respectively). Heavy warm-up resulted... [to full text]