Poster Session N - Cardiovascular Medicine and Research 2.
Introduction: Physical fitness is a complex outcome of long- and short term cardiovascular-, respiratory-, metabolic- and neurohormonal adaptation to exercise. Heart rate variability (HRV) could be an indirect cardiac indicator of the sports adaptation of the autonomic nervous system.
Aim: We aimed to examine the short-term HRV variables, characterizing autonomic regulation, during exercise among youth elite athletes.
Methods: During cardiopulmonary exercise tests at maximum and in the following 5 min cool-down (CD), we determined time and frequency domain indicators of HRV and their changes compared to the resting value. The measurements were made with Polar transmitters; the analysis was done with Kubios software and in Python development environment.
Results: We analyzed the results of 228 youth water polo players (age: 15 [14-16]year, training: 15 [12.3-17.6]hour/week, m: 128). The average heart rate during maximal exercise was 189 [184-194]BPM, while during CD it was 135 [128-143]BPM. HRV parameters measured during maximal exercise were as follows: AVNN: 317.3 [309.2-327.0]ms; SDNN: 2.5 [2.2-2.8]ms; RMSSD: 3.7 [3.2-4.2]ms; pNN50: 0 [0-0]%; LFpow: 0.2 [0.1-0.4]ms2; HFpow: 0.3 [0.2-0.5]ms2; LF/HF: 0.8 [0.5-1.3], during CD: AVNN: 445.1 [421.0-467.8]ms; SDNN: 6.3 [5.0-7.9]ms; RMSSD: 4.1 [3.2-5.4]ms; pNN50: 0 [0-0]%; LFpow: 29.1 [15.4-57.6]ms2; HFpow: 5.3 [2.5-14.9]ms2; LF/HF: 5.9 [3.3-8.9]. The relative RMSSD measured during exercise and CD, as well as the relative SDNN measured during exercise showed a positive correlation with the training hours. The exercise and CD RMSSD and pNN50 were negatively correlated with the running time. The oxygen uptake measured at the anaerobic threshold showed a negative correlation with the exercise relative AVNN and LFpow, as well as the CD relative AVNN and SDNN values. The maximal oxygen uptake was negatively correlated with the exercise HFpow, the exercise relative AVNN, SDNN, and HFpow, as well as the CD relative AVNN and SDNN parameters.
Conclusion: According to our results, the reduction of several HRV parameters characterizing parasympathetic tone shows a negative correlation with some exercise parameters indicating fitness, referring to a more effective effect of sympathetic tone.
Funding: RRF-2.3.1-21-2022-00004; K135076; TKP2021-NKTA-46; EFOP-3.6.3-VEKOP-16-2017-00009; ÚNKP-23-3-II-SE-36