The aim was to assess the cardiac function of healthy women by applying the spiritual intervention, i.e. a prayer, in different circumstances. Methods: a descriptive, intervention study design was used. The data were collected during three weeks in May, 2019. A total of 39 women with normal physiologic health at the age of 25-50 years who considered themselves as religious persons participated in the study. The cardiac-spiritual intervention process consisted of nine episodes with the heart rate measurements applied. For data recording and analysis researchers used ECG system Kaunas-Load that was developed at Lithuanian University of Health Sciences. With the ECG record RR interval, HRV and ST interval amplitude were analysed. The Spiritual Needs Questionnaire (SpNQ) was used to assess the spiritual needs of participants. Data were recorded and analyzed using the Statistical Package for Social Sciences (IBM SPSS Statistics) version 25.0. Results: Religious and Existential needs were the most important spiritual needs for women. Existential needs the most strongly correlated with Religious needs and needs of Inner peace. The reactions to prayer were more expressed in women of older age. The general tendency of increase in RR average during the praying episodes was observed; at resting position women's heart rate decreased. During all phases of the study, the HR spectrum power was higher in the group of women with stronger expression of their unmet spiritual needs and the general physiologic condition of these women was also better. The increasing significant (< 0.1) relationship between spiritual needs scores and changes of women heart rate was observed during pray episodes of spiritual intervention process. Conclusions: changes in the heart rate of healthy women during separate episodes of spiritual intervention demonstrated the reaction toward prayer. Individual or group praying caused the calming effect for women under the study. Assessment of unmet spiritual needs of women and the relationship with the heart rate changes during spiritual intervention process supported the idea that heart activity depends on the level of personal religiosity and spirituality.