Varijabilnost srĉane frekvencije tokom oporavka od testova za procenu energetskih kapaciteta uaerobnim i anaerobnim sportovima

Abstract

Kardiovaskularni odgovor na različite fiziološke stimuluse moguće je pratiti putem analize razlika utrajanju srčanih ciklusa – varijabilnosti srčane frekvencije (VSF). Ona ima široku primenu u oblasti sporta budući da je monitoring putem VSF krajnje bezbedan, jeftin i jednostavan za izvođenje. Njeni indeksi se razlikuju između treniranih i netreniranih, uvećavaju se u odgovoru na trening izdržljivosti, a padaju ukoliko dođe do pojave zamora i pretreniranosti. Cilj istraživanja je bio da se utvrdi da li postoji razlika između sportista iz grupe dominantno anaerobnih sportova (AN), sportista iz grupe dominantno aerobnih sportova (AE) i nesportista (NS) u VSF u miru i u autonomnom odgovoru nakon testova za ispitivanje aerobnog i anaerobnog energetskog kapaciteta, kao i da li postoji povezanost između rezultata ovih testova i parametara VSF unutar grupa. Ispitivanju je pristupilo 75 sportista koji su zatim razvrstani na osnovu dominantnih metaboličkih zahteva treniranog sporta tako da ih je u AN grupi bilo 36 (20.7±2.4 god., 1.83±0.07 cm, 83.5±12.3 kg), a u AE grupi 39 (20.5±1.9 god., 1.79±0.06 cm, 75.6±8.1 kg). U NS grupi bilo je 39 ispitanika (21.4±1.8 god., 1.82±0.06 cm, 83.1±11.2 kg) iste uzrasne dobi i sličnih demografskih karakteristika sa sportistima. Ispitanici su u različitim danima bili podvrgnuti anaerobnom Vingejt testu (WanT) i inkrementalnom testu za određivanje maksimalne aerobne potrošnje (VO₂max). VSF je registrovana Polar pulsmetrom, a podaci su obrađeni u Polar ProTrainer 5 softveru. Sportisti iz AE grupe imali su više vrednosti parametara SDNN (standardna devijacija NN intervala (interval između R zubca jednog do R zubca narednog, normalnog QRS kompleksa)) i RMSSD (kvadratni koren srednje vrednosti sume kvadrata razlika) merene u mirovanju u odnosu na ostale grupe. Razlike u VSF između grupa tokom oporavka od WanT i VO₂max testa nije bilo. U AN grupi parametar SDNN umereno negativno je korelirao sa vrednostima prosečne snage (eng. mean power, MP) i maksimalne snage (eng. peak power, PP) u VSF u miru i tokom oporavka od WanT. Parametar lnLF (prirodni logaritam vrednosti niskofrekventnog opsega spektra) pokazivao je istovetnu korelaciju u miru sa MP i PP, a tokom oporavka od Want umereno negativno je korelirao samo sa vrednosti PP. Parametar VSF u miru – lnHF (prirodni logaritam vrednosti visokofrekventnog opsega spektra) umereno negativno je korelirao sa MP. Odnos niskofrekventnog prema visokofrekventnom opsegu spektra (LF/HF) pokazivao je umerenu pozitivnu povezanost sa vrednosti maksimalne snage prema kilogramima telesne teţine (PP/kg) i u miru i tokom oporavka od WanT. U AE i NS grupi nisu uočene povezanosti sa rezultatima WanT u miru i oporavku. Kod AE sportista u miru vrednost prosečnog NN intervala (NNRR) umereno pozitivno je korelirala sa vršnom vrednošću VO₂ (VO₂ pik), a umerena negativna povezanost ispoljena je za vrednost maksimalnog broja otkucaja na kraju VO₂max testa (HRmax) sa SDNN, SD1 (kratkoročna varijabilnost Poenkareovog zapleta), RMSSD, pNN50 (procentualni udeo NN intervala duţih od 50 ms u ukupnom broju NN intervala), ukupnom snagom spektra (TP), vrednosti opsega spektra vrlo niskih frekvencija (VLF), vrednosti niskofrekventnog opsega spektra (LF), lnLF, vrednosti visokofrekventnog opsega spektra (HF) i lnHF. Umerena negativna korelacija postojala je i za vrednost srčane frekvencije na ventilatornom pragu (HRvt) sa vrednostima SDNN, SD1 i RMSSD. Tokom oporavka od VO₂max testa kod ovih sportista postojala je umerena negativna povezanost vrednosti VO₂pik sa lnHF, vrednosti visokofrekventnog opsega spektra izraženu u normalizovanim jedinicma (HFnu) i LF/HF, a VO₂pik je i umereno pozitivno korelirao sa HF. U NS grupi naglašeni parasimpatički (PNS) markeri VSF (NNRR i pNN50) u miru dovođeni su u negativnu vezu sa progesijom srčanog ritma tokom VO₂max testa, a dominacija u niskofrekventnom opsegu spektra bila je u direktnom odnosu sa ostvarenim vršnim vrednostima VO₂. U aerobnim sportovima u VSF u miru dominiraju PNS obeležja. Niska VSF u miru i u uslovima oporavka od WanT karakteristika je sportista iz anaerobne grupe sportova. Naglašenost pojedinih PNS markera u miru i uslovima oporavka od VO₂max testa moguće ukazuje na bolji aerobni kapacitet u sportovima izdržljivosti. Među nesportistima bolju aerobnu izdržljivost imaju oni kod kojih u miru postoji dominacija u niskofrekventnom opsegu spektra.

Cardiovascular response to various physiological stimuli is possible to monitor through heart cycle length analysis – heart rate variability (HRV). HRV has a vast application in sport concerning that monitoring via HRV is absolutely safe, cheap and simple for use. HRV indexes are different among trained and untrained subjects, they are augmented in response to endurance training and lowered in the case of fatigue and overtraining. The goal of this research was to determine if there is a difference between athletes from dominantly anaerobic sports (AN), athletes from dominantly aerobic sports (AE) and non-athletes (NA) in resting HRV and in autonomic response after tests for determination of anaerobic and aerobic capacity, and also to examine if there is a correlation of results of these tests and HRV parameters intra-group. The research included 75 athletes who were classified in two groups according to the dominant metabolic demands of the trained sport – the AN group consisted of 36 athletes (20.7±2.4 yrs, 1.83±0.07 cm, 83.5±12.3 kg), and the AE group consisted of 39 athletes (20.5±1.9 yrs, 1.79±0.06 cm, 75.6±8.1 kg). In the NA group there were 39 participants (21.4±1.8 yrs,1.82±0.06 cm, 83.1±11.2 kg) who were of same age and similar demographic characteristics as athletes. The examinees were subjected to anaerobic Wingate test (WanT) and incremental test for maximal aerobic expenditure (VO₂max) in different days. HRV was registered with Polar heart rate monitor and the data were analyzed in Polar Pro Trainer 5 software. Athletes from AE group had higher values of resting SDNN (standard deviation of NN intervals (normal-to-normal intervals – intervals from the peak of one R wave to the peak of subsequent R wave of normal QRS complexes) and RMSSD (root mean square of the successive squared differences) in regard to other two groups. We did not find any differences in HRV between groups during the recovery from WanT and VO₂max test. SDNN parameter correlated moderately negatively with mean power (MP) and peak power (PP) in rest and during recovery from WanT in AN group. The natural logarithm of low frequency spectral band (lnLF) showed the same type of correlation in rest with MP and PP, and it correlated moderately negatively with PP in recovery from WanT. The resting HRV parameter – lnHF (natural logarithm of high frequency spectral band) moderately negatively correlated with MP. The low frequency spectral band to high frequency spectral band relation (LF/HF) showed moderately positive correlation with PP in respect to kilograms of body weight (PP/kg) in rest and during recovery from WanT. In AE and NA group no correlations were seen with the results of WanT in HRV at rest and during recovery. In AE group resting NNRR (average NN interval) moderately positively correlated with peak VO₂ value(VO₂peak), and moderate negative correlation existed for maximal heart rate at the end of VO₂max test (HRmax) with SDNN, SD1 (short time variability of Pointcare plot), RMSSD, pNN50 (the percentage of NN intervals longer than 50 ms in overall number of NN intervals), total spectral power (TP), very low frequency spectral power (VLF), low frequency spectral power (LF), lnLF, high frequency spectral power (HF) and lnHF. Moderate negative correlation existed for heart rate at ventilatory treshold (HRvt) with the values of SDNN, SD1 and RMSSD. During recovery from VO₂max test athletes from AE group had moderately negative correlation of VO₂peak with lnHF, high frequency spectral power expressed in normalized units (HFnu) and LF/HF, аnd VO₂peak did moderately positively correlate with HF. In NA group augmented resting parasympathetic HRV markers (NNRR and pNN50) were in negative relation with heart rate progression during VO₂max test, and a dominance in low frequency spectral band was in direct relation with achieved values of VO₂peak. In aerobic sports PNS tone is marked. Reduced HRV in rest and during the recovery from WanT is seen in athletes from anaerobic sports. Augmentation of some PNS parameters in rest and recovery conditions from VO₂max test possibly suggests better aerobic capacity in endurance sports. Among non-athletes better aerobic endurance was reserved for the ones who showed dominance in low frequency spectral band in resting-state HRV.