Učinek molitve na variabilnost srčne frekvence v mirovanju

Žunkovič, Breda (author), Bajrović, Fajko (mentor), Kejžar, Nataša (co-mentor)

Izhodišča Variabilnost srčne frekvence (angl. heart rate variability, HRV) odraža vpliv avtonomnega živčevja in metabolnih dejavnikov na sinoatrijski vozel. Majhna HRV v mirovanju je neodvisen napovedni dejavnik za srčno-žilne bolezni in mortaliteto. Tako je v zadnjih letih eksponentno naraslo tudi število raziskav o dejavnikih, ki vplivajo na HRV. Raziskave so pokazale, da lahko diametralno različna življenjskega sloga, kot sta npr. redna vzdržljivostna telesna vadba in meditacija, na dolgi rok povečata parametre HRV, ki odražajo modulatorno aktivnost parasimpatikusa (PSIM). Molitev je najbližji korelat meditativnim tehnikam v našem kulturnem okolju in je globalno gledano pogosta praksa, vendar njen učinek na HRV še ni bil dovolj raziskan, rezultati maloštevilnih raziskav, pa niso enotni. Namen dela in hipoteze Namen naše raziskave je proučiti, ali molitev kratkoročno in dolgoročno vpliva na HRV v mirovanju, predvsem na tiste parametre, ki kažejo na PSIM modulacijo srčne frekvence. Postavili smo naslednje hipoteze: 1. Med molitvijo se povečajo HRV parametri, ki kažejo na PSIM modulacijo srčne frekvence. 2. Povečanje HRV parametrov, ki kažejo na PSIM modulacijo srčne frekvence, med molitvijo je večje pri preiskovancih, ki redno molijo, kot pri preiskovancih, ki ne molijo redno. 3. Pri preiskovancih, ki redno molijo, so v primerjavi s preiskovanci, ki ne molijo redno, HRV parametri v mirovanju, ki kažejo na PSIM modulacijo srčne frekvence, višji. Metode Pri 78 odraslih preiskovancih, ki redno molijo (49 žensk, starost 37±11 let), in pri 50 odraslih preiskovancih, ki ne molijo (35 žensk, 35±8 let), smo v mirovanju v sedečem položaju merili frekvenco dihanja in posneli elektrokardiogram (EKG). Osnovni protokol raziskave je vseboval pet zaporednih faz: mirovanje, molitev, mirovanje, recitacija nereligiozne pesmi in ponovno mirovanje. Da bi ocenili morebiten učinek časa in morebiten prenešen učinek prve intervencije na drugo, smo v podskupini preiskovancev vrstni red intervencij zamenjali (recitacija pred molitvijo). Iz 5 minutnih intervalov iz posameznih faz protokola smo izračunali HRV parametre: SDNN (angl. standard deviation of NN intervals), ki predstavlja celotno HRV; RMSSD (angl. root mean square of successive differences), ki odraža PSIM modulacijo srčne frekvence; in HF (angl. high frequency, 0,15-0,40 Hz), ki prav tako odraža PSIM modulacijo srčne frekvence. Primarni cilji so bili odgovoriti na zastavljene tri hipoteze. Za testiranje prve hipoteze smo s parnim t-testom primerjali povprečja HRV parametrov pred in med molitvijo pri vseh preiskovancih. Za testiranje druge hipoteze smo s t-testom za neodvisna vzorca primerjali povprečne spremembe HRV parametrov med molitvijo med skupinama preiskovancev (molilci in kontrole). Za testiranje tretje hipoteze smo s t-testom za neodvisna vzorca primerjali povprečne vrednosti HRV parametrov med skupinama (molilci in kontrole) v prvem mirovanju. Sekundarni cilji so bili ugotoviti, ali se učinek molitve na HRV parametre razlikuje od recitacije in glede na spol in vrstni red intervencij. Za oceno učinka spola in vrstnega red intervencij na učinek molitve smo uporabili linearni regresijski model. Za primerjavo učinkov obeh intervencij smo z linearnim mešanim modelom ocenjevali povprečno spremembo HRV parametrov med intervencijo. V modelu smo opazovali povprečno razliko v učinkih molitve in recitacije, ki je bila prilagojena na možen prenešen učinek iz prve intervencije in na učinek časa. Rezultati Med molitvijo se je povprečna vrednost RMSSD statistično značilno zmanjšala (p = 0,001), povprečna vrednost HF pa nakazano zmanjšala (p = 0,038). Povprečno zmanjšanje RMSSD med molitvijo se med skupino molilcev in kontrolno skupino ni statistično značilno razlikovalo (p = 0,507). Prav tako se skupini preiskovancev v prvem mirovanju nista statistično značilno razlikovali v vrednostih HRV parametrov (p = 0,428, p = 0,645 in p = 0,691 za parametre SDNN, RMSSD in HF). Dodatno smo ugotovili, da obstaja možnost, da se povprečna vrednost RMSSD med molitvijo pri moških bolj zmanjša kot med recitacijo (p = 0,022). Možno je, da je učinek molitve povezan s spolom in vrstnim redom intervencij skupaj z njuno interakcijo (p = 0,007 in p = 0,046 za spol in vrstni red); moškim, ki so najprej recitirali, se je RMSSD med molitvijo še posebej znižal. Prenešenega učinka prve intervencije na drugo nismo uspeli statistično dokazati. Zaključki Z rezultati raziskave nismo potrdili zastavljenih hipotez. V nasprotju z našo predpostavko sta se med tiho molitvijo HRV parametra, ki odražata PSIM modulacijo srčne frekvence, znižala in ne zvišala. Ti rezultati kažejo, da se je med molitvijo PSIM modulacija srčne frekvence zmanjšala in da je bil ta učinek nekoliko večji pri moških, kot pri ženskah. Trend večjega znižanja RMSSD med molitvijo glede na recitacijo kaže na možnost, da molitev učinkuje na HRV preko dodatnih mehanizmov in ne samo s procesiranjem govora.

• Language: Slovenian
• Keywords: Variabilnost srčne frekvence, molitev, parasimpatik, avtonomno živčevje
• Work type: Doctoral dissertation
• Organization: MF - Faculty of Medicine
• Year: 2023
• PID: 20.500.12556/RUL-153420
• Publication date in RUL: 05.01.2024

Secondary language

• Language: English
• Title: The effect of prayer on resting heart rate variability

Abstract

Background Heart rate variability (HRV) reflects influences of autonomic nervous system and metabolic factors on sinoatrial node. Decreased HRV is an independent risk factor for cardiovascular diseases and all-cause mortality, hence the research of various factors that might affect HRV has been growing exponentially. Studies showed that two very different life styles, like regular physical exercise and meditation, both increase HRV parameters, which reflect parasympathetic (PSYM) modulation of heart rate. Prayer is a common practice worldwide and represents the closest correlate to meditation in the West, however its effects on HRV are unclear. Objectives and hypotheses The primary aim of this study was to examine short term and long term effect of silent prayer on HRV parameters, especially those reflecting PSYM modulationof heart rate. For that we made three hypotheses: 1. HRV parameters, which reflect PSYM modulation of heart rate, increase during silent prayer. 2. The increase of HRV parameters, which reflect PSYM modulation of heart rate, during silent prayer is greater in those subjects, who regularly pray, than in those subjects, who do not pray. 3. The baseline HRV parameters, which reflect PSYM modulation of heart rate, are greater in those subjects, who regularly pray, than in those subjects, who do not pray. Secondary aims were to evaluate whether the effect of prayer on HRV parameters differed from the effect of recitation on HRV, and regarding to sex and order of interventions. Methods ECG and respiratory rate were recorded continuously in 78 subjects (49 females,age 37±11), who prayed regularly, and in 50 subjects (35 females, age 35±8), who did not pray at all. The main study protocol included five consecutive phases: sitting at rest, silent prayer, sitting at rest, silent recitation of secular song lyrics, and sitting at rest. To assess the effect of time passed and the carry-over effect on the effect of prayer on HRV, the order of interventions was reversed in a subgroup of subjects (recitation before prayer). Standard HRV parameters were calculated from the 5-minute intervals of each protocol phases: SDNN (reflecting combined PSYM and sympathetic heart rate modulation), RMSSD and HF (both reflecting PSYM heart rate modula-tion). For first hypothesis testing, paired sample t-test was used to compare the mean values of HRV parameters before and during prayer. For second hypothesis testing, the independent samples t-test was used to compare the mean changes of HRV parameters during prayer between the two subject groups (prayers and controls). For third hypothesis testing, the unpaired t-test was used to compare the mean values of baseline HRV parameters between the two subject groups (prayers and controls). To assess the effects of sex and order of prayer before or after recitation on the effect of prayer, a linear regression model was fitted. To compare the effects of the two interventions, the mean change in HRV parameters during prayer was compared with the mean change during song recitation using linear mixed effect model with patient random intercept. Since the study was designed as across-over study, the result was adjusted for the period effect (the effect of time independent of intervention) and the possible carry-over effect. Results The mean value of RMSSD statistically significantly decreased during prayer compared with the resting phase just before prayer (p=0.001), and the mean value of HF tended to decrease during prayer (p=0.038). The decrease of RMSSD during prayer did not statistically significantly differ between the group of prayers and the control group (p=0.507). The baseline mean values of HRV parameters did not statistically significantly differ between the group of prayers and the control group (p=0.428,p=0.645 and p=0.691 for SDNN, RMSSD and HF). Additionally, the decrease of RMSSD tended to be greater during prayer than during recitation in men (p=0.022). Sex and order of interventions, together with their interaction, tended to correlate with the effect of prayer on RMSSD (p=0.007 and p=0.046 for sex and order of interventions); the decrease of RMSSD was greater in those men, who prayed after recitation. The carry-over effect was not statistically significant. Conclusions The study results do not support the hypotheses. Contrary to our assumption, HRV parameters, reflecting PSYM modulation of heart rate decreased during silent prayer. These results suggest, that during silent prayer PSYM modulation of heart rate decreased and this decrease tended to be greater in men. The trend of greater decrease of RMSSD during prayer than during recitation suggests that it can not be explained only by language processing and that other mechanisms are involved.

• Keywords: heart rate variability, prayer, parasympathetic, autonomic nervous system