Correlation between the intensity of pulse longevity accumulation and the rate of oxygen demand formation and blood lactate accumulation in performing limiting cyclic exercises of different duration

The purpose of the study was to search for the relationship of Pulse Debt Accumulation Intensity (PDАI) with the rate of formation of oxygen demand and the accumulation of lactate in the blood during the performance of limiting cyclic exercises of various durations.Methods: 14 athletes‑cyclists (1st category, 20 ± 3 years, MОC — 52.9 ± 5.10 ml / min / kg), performed a series of bicycle ergometric exercises of maximum power on different days at a fixed duration of 10, 30, 60, 120, 360 and 1800 s. Based on the pulse sums of the five‑minute recovery (minus the pre‑start HR level) and the exercise time, the intensity of accumulation of pulse debt was calculated for all exercises in each subject. The rate of accumulation of lactate concentration in the blood (SNCL) and the rate of formation of oxygen demand (OCR) were also calculated.Results: SOCS, SNCL and PDАI have a close non‑linear relationship with exercise time (respectively: r2 = 0.84, r2 = 0.91, r2 = 0.96, at p < 0.05), as well as with relative exercise power (respectively: r2 = 0.80, r2 = 0.86, r2 = 0.90, at p < 0.05). INPD has a close relationship with SRCS and SNCL (respectively: r2 = 0.80, r2 = 0.94, p < 0.05).Conclusions: The results of the study make it possible to use the INPD heart rate indicator for a fairly reliable determination of exercise intensity and for predicting the level of lactate accumulation, and on this basis, determining the direction of the exercise and normalizing the training load.