The effects of Yoga Nidra on the cardiovascular system of pregnant women

Abstract

Background: Pregnancy involves cardiovascular alterations that include changes in cardiac output, systemic vascular resistance, blood volume, stroke volume, heart rate (HR) and heart size and blood pressure (BP). The cardiovascular system is altered as a natural response to the increased metabolic demands of pregnancy, especially in relation to BP and HR. Abnormal alterations within the cardiovascular system during pregnancy may put a pregnant woman at risk for developing cardiovascular complications during pregnancy. These complications can include preeclampsia, eclampsia, and other hypertensive disorders of pregnancy (to name a few). In many cases, the maternal stressors that are uniquely associated with pregnancy can put further strain on the maternal cardiovascular system. Yoga nidra is an in-depth relaxation technique with promising therapeutic benefits for the cardiovascular system. The aim of this study was to investigate the effects of a single 15-minute yoga nidra practice on the systolic (SBP) and diastolic (DBP) blood pressure (BP) and the heart rate (HR) of pregnant women when compared with baseline and passive relaxation measurements (sitting). Methods: A total of 31 pregnant volunteers (> 13 weeks gestation) were recruited through non-probability sampling in the Tshwane and Johannesburg regions of Gauteng, South Africa. An experimental pre-test, post-test study design was used to observe the effects of yoga nidra on the cardiovascular system of pregnant women. BP and HR measurements were obtained using an OMRON HEM-7280T-E blood pressure monitor at baseline, after 15 minutes of sitting (passive relaxation) and after 15 minutes of yoga nidra (active relaxation), with a 15-minute washout period between sitting and yoga nidra (normal activity and walking). Data were analysed using dependent t-tests and repeated measures analyses of variance (RM-ANOVA). Results: Dependent t-test results showed reductions in SBP (103.8 mmHg vs 101.2 mmHg, p = 0.003) and HR (79.6 bpm vs 75.0 bpm, p < 0.001) post-yoga nidra, while reductions in SBP (103.8 mmHg vs 101.7 mmHg, p = 0.006) and DBP (68.3 mmHg vs 66.4 mmHg, p = 0.014) were observed post-sitting. When comparing post-yoga nidra and post-sitting results, DBP and SBP showed no differences, while HR were lower post-yoga nidra (75.0 bpm) than post-sitting (79.0 bpm) (p < 0.001). Further investigation through RM-ANOVA revealed that yoga nidra had a significant effect on the HR (p = 0.002) of women who were in the third trimester of pregnancy. The mean HR after yoga nidra was 72.6 bpm (95% CI 65.97, 79.19) among women in the second trimester and 76.5 bpm, 95% CI (70.69, 82.36) among women in the third trimester. Conclusion: The findings demonstrate a significant reduction in HR post-yoga nidra when compared with the post-sitting and baseline measurements of pregnant women, more specifically, women in the third trimester of pregnancy. This lowered HR, which was not observed post-sitting, may indicate parasympathetic activation after yoga nidra. Essentially, the results of this study indicate that yoga nidra could be recommended during the third trimester of pregnancy to assist in lowering HR during the final stages of pregnancy.

Agtergrond: Swangerskap behels kardiovaskulêre veranderinge, en in baie gevalle, moederlike stres. Joga nidra is 'n diepgaande ontspanningstegniek met belowende terapeutiese voordele. Die doel van die studie was om die uitwerking van 'n enkele 15-minute joga nidra-sessie op die sistoliese (SBD) en diastoliese bloeddruk (DBD) en hartkloptempo (HK) van swanger vroue te ondersoek wanneer dit met die basislyn en passiewe meting (sit) vergelyk word. Metodes: 'n Totaal van 31 swanger vrywilligers (>13 weke swanger) is gewerf deur 'n niewaarskynlikheidsteekproefneming in die Tshwane- en Johannesburg-streke van Gauteng, Suid-Afrika. 'n Eksperimentele voortoets, natoets-studie-ontwerp is gebruik om die uitwerking van joga nidra op die kardiovaskulêre stelsel van swanger vroue waar te neem. BD- en HK-metings is geneem deur die OMRON HEM-7280T-E-bloeddrukmonitor by basislyn; na 15 minute van sit (passiewe ontspanning) en na 15 minute van joga nidra (aktiewe ontspanning), met 'n 15-minuut-uitspoelperiode tussen sit en joga nidra (normale aktiwiteit en stap). Data is deur afhanklike t-toetse en herhaalde metingontleding van afwykings (RM-ANOVA) ontleed. Resultate: Afhanklike t-toetse van basislyn in vergelyking met beide intervensies toon verlaging in SBD (103.8 mmHg vs 101.2 mmHg, p = 0.003) en HK (79.6 bpm vs 75.0 bpm, p < 0.001) na-joga nidra, terwyl verlagings in SBD (103.8 mmHg vs 101.7 mmHg, p = 0.006) en DBD (68.3 mmHg vs 66.4 mmHg, p = 0.014) tydens na-sit waargeneem is. By vergelyking van na-joga nidra en na-sit-resultate het BDD en SBD geen verskille getoon nie, terwyl HK laer was na joga nidra (75.0 bpm) as na sit (79.0 bpm) (p < 0.001). Verdere ondersoek deur RM-ANOVA het getoon dat joga nidra 'n beduidende uitwerking op die HK (p = 0.002) gehad het van vrou in die derde trimester van swangerskap. Die gemiddelde HK na joga nidra was 72.6 bpm, 95% CI [65.97, 79.19] onder vroue in die tweede trimester en 76.5 bpm, (95% CI 70.69, 82.36) onder vroue in die derde trimester. Samevatting: Die bevindings toon 'n beduidende verlaging in HK na joga nidra in vergelyking met na-sit en basislynmeting van swanger vroue, meer spesifiek, vroue in die derde trimester van swangerskap. Hierdie laer HK, wat nie na-sit waargeneem is nie, dui moontlik op parasimpatiese aktivering na joga nidra. Die resultate van hierdie studie toon dat joga nidra tydens die derde trimester van swangerskap aanbeveel moet word om HK tydens die finale stadiums van swangerskap te verlaag.

Isendlalelo: Ukukhulelwa kufaka phakathi ukuguqulwa kwenhliziyo nemithambo yegazi futhi, ezimweni eziningi, ukucindezeleka komama. I-Yoga nidra iyindlela yokuphumula ejulile enezinzuzo ezithembisayo zokwelapha. Inhloso yalolu cwaningo bekuwukuphenya imiphumela yomkhuba owodwa wemizuzu eyi-15 ye-yoga nidra kusistolikhi kanye nedayastokhi umfutho ophezulu wegazi kanye nesilinganiso senhliziyo sabesifazane abakhulelwe uma kuqhathaniswa nesisekelo kanye nezilinganiso zokuphumula ezingenzi lutho (uhlezi). Izindlela: Ithothali yamavolontiya akhulelwe angama-31 (> amasonto ayi-13 okukhulelwa) abuthwa ngamasampula okungewona amathuba esifundeni saseTshwane naseGoli eGauteng, eNingizimu Afrika. Umklamo wokuhlola wangaphambi kokuhlolwa, wangemuva kokuhlolwa wasetshenziselwa ukubuka imiphumela ye-yoga nidra ohlelweni lwenhliziyo nemithambo yegazi yabesifazane abakhulelwe. Izilinganiso zomfutho ophezulu wegazi nesilinganiso senhliziyo zitholwe kusetshenziswa i-OMRON HEM-7280T-E yokuqapha umfutho wegazi ekuqaleni; ngemuva kwemizuzu eyi-15 uhlezi (ukuphumula kancane) nangemuva kwemizuzu eyi-15 ye-yoga nidra (ukuphumula okusebenzayo), nenkathi yokugeza eyimizuzu eyi-15 phakathi kokuhlala kanye ne-yoga nidra (umsebenzi ovamile nokuhamba). Idatha yahlaziywa kusetshenziswa ukuhlola kuka-t okuncike kanye nokuhlaziywa kwezinyathelo eziphindaphindiwe zokuhluka (RM-ANOVA). Imiphumela: Imiphumela yokuhlolwa kwe-t encikile kusukela kuyisisekelo uma kuqhathaniswa nakho kokubili ukungenelela ibonise ukuncipha kwe-SBP (103.8 mmHg vs 101.2 mmHg, p = 0.003) kanye nesilinganiso senhliziyo (79.6 bpm vs 75.0 bpm, p <0.001) yoga nidra-yangemuva, kuyilapho ukuncipha kweSolikhi (103.8 mmHg vs 101.7 mmHg, p = 0.006) kanye nedayastolikhi (68.3 mmHg vs 66.4 mmHg, p = 0.014) kubhekwe ngemuva kokuhlala. Uma kuqhathaniswa nemiphumela ye-yoga nidra yangemuva kanye nokuhlala kwangemuva, i-DBP ne-SBP ayizange ibonise umehluko ngenkathi isilingangiso senhliziyo sasingaphansi kwe-yoga nidra ngengemuva (75.0 bpm) kunokuhlala kwangemuva (79.0 bpm) (p < 0.001). Uphenyo olwengeziwe nge-RM-ANOVA luveze ukuthi i-yoga nidra ibe nomthelela omkhulu kuyisilinganiso senhliziyo (p = 0.002) yabesifazane ababe kuyitrayisimista yesithathu yokukhulelwa. Isilinganiso senhliziyo ngemuva kwe-yoga nidra sasinga-72.6 bpm, (95% CI 65.97, 79.19) phakathi kwabesifazane kutrayisimista yesibili kanye no-76.5 bpm, (95% CI 70.69, 82.36) phakathi kwabesifazane ku-trayisimista yesithathu. Isiphetho: Okutholakele kukhombisa ukuncipha okukhulu kwe-silinganso senhliziyo kuyi-yoga nidra yangemuva uma kuqhathaniswa nezilinganiso zangemuva kokuhlala kanye nesisekelo sabesifazane abakhulelwe, ikakhulukazi, abesifazane ku-trayisimista yesithathu yokukhulelwa. Lokhu kwehlise isilinganiso senhliziyo, engazange ibonwe ngemuva kokuhlala, kukhombisa ukusebenza kwekomuzwa ongagcwele ngemuva kwe-yoga nidra. Empeleni, imiphumela yalolu cwaningo ikhombisa ukuthi i-yoga nidra inganconywa ngesikhathi setrayisimista yesithathu yokukhulelwa ukusiza ekwehliseni iSilinganiso Senhliziyo phakathi nezigaba zokugcina zokukhulelwa.