European Journal of Cardiovascular Medicine

Cardiovascular disease (CVD) remains the leading global cause of morbidity and mortality, with modifiable autonomic and hemodynamic factors—such as resting blood pressure (BP), heart rate (HR), and heart rate variability (HRV)—serving as important risk indicators and therapeutic targets. Mind–body practices have drawn increasing interest for their potential to favorably modulate autonomic balance and downstream cardiovascular physiology. Among these practices, OM meditation (also described as OM chanting) is notable for its slow, prolonged expiratory phonation and attentional focus, features that could engage cardiorespiratory coupling and vagal pathways relevant to BP and HR regulation. [1–3]

Evidence specifically probing OM practices suggests acute autonomic shifts compatible with parasympathetic engagement. Early laboratory work reported reductions in HR during OM meditation compared with non-targeted thinking in experienced practitioners, implying a shift toward vagal predominance. [1] More recently, mechanistic recordings during OM chanting demonstrated robust synchronization among respiration, RR-intervals, and systolic blood pressure, including emergence of 0.1-Hz cardiovascular oscillations despite breathing near ~0.05 Hz—findings consistent with resonance phenomena that can enhance baroreflex function. [2] In controlled settings, OM chanting has also been associated with immediate changes in HRV indices, with effects differing by experience level or clinical status, further supporting a rapid autonomic response to the practice. [3,4]

Beyond OM-specific data, convergent literature indicates that slow, controlled breathing and mindfulness practices can increase vagally mediated HRV and may lower resting HR and BP. A comprehensive meta-analysis of voluntary slow breathing showed consistent increases in vagally mediated HRV across single-session and multi-session paradigms. [5] In parallel, randomized trials of mindfulness programs adapted for hypertension (Mindfulness-Based Blood Pressure Reduction, MB-BP) have demonstrated clinically meaningful reductions in systolic BP versus control over six months, alongside improvements in self-regulation behaviors that influence BP. [6] Complementary evidence from systematic reviews of breathing exercises supports small-to-moderate decreases in BP and HR, reinforcing the physiologic plausibility that breath-centered contemplative practices can benefit cardiovascular regulation. [7]

However, important gaps remain. Many OM-focused studies examine acute or immediate effects, enroll small or selected samples, or emphasize neurophysiologic mechanisms rather than clinically relevant endpoints. Few controlled studies have tested an OM meditation program over several weeks in generally healthy adults with objective cardiovascular outcomes measured repeatedly. To address this gap, we conducted a randomized comparative study evaluating an 8-week OM meditation intervention versus no intervention on BP, HR, and HRV in healthy adults. We hypothesized that OM meditation would reduce BP and HR and increase HRV over time relative to controls.

Study Design: This study employed a comparative study design to assess the impact of OM meditation on cardiovascular parameters. Participants were randomly assigned to either the intervention group (OM meditation) or the control group (no intervention).

Participants: Inclusion criteria encompassed adults aged 25–60 years and no history of cardiovascular disease. Exclusion criteria included pregnancy, psychiatric disorders, and participation in other stress-reduction programs. Participants were recruited through local advertisements and screened for eligibility.

Sample Size Calculation: Sample size determination was based on prior studies examining the effects of meditation on cardiovascular parameters. A study by Weiss et al. (2024) utilized a sample size of 29 participants to assess the impact of Metta meditation on health-promoting protective factors in individuals with cardiovascular disease [8]. Given the exploratory nature of this study and the need for adequate statistical power, a sample size of 30 participants per group was deemed appropriate to detect significant differences between groups with a power of 80% and a significance level of 0.05.

Intervention: The OM meditation program consisted of daily 20-minute sessions over 8 weeks, guided by certified instructors. Participants in the control group received no intervention during the study period.

Outcome Measures: Primary outcomes included systolic and diastolic blood pressure, heart rate, and heart rate variability (HRV). Measurements were taken at baseline, 4 weeks, and 8 weeks.

Measurement of Cardiovascular Parameters: All cardiovascular parameters were measured at three time points: baseline (prior to the intervention), 4 weeks, and 8 weeks. Blood pressure (BP) was recorded using a calibrated digital sphygmomanometer in a seated position after the participant had rested for at least 5 minutes. Three consecutive readings were obtained at 2-minute intervals, and the average was used for analysis. SBP and DBP were documented in mmHg. Heart rate (HR) was simultaneously measured by the digital device, recorded in beats per minute (bpm).

Heart rate variability (HRV), as a measure of autonomic function, was assessed using a validated portable HRV monitor. Participants were instructed to remain seated and relaxed for 5 minutes during the measurement. The time-domain parameter standard deviation of normal-to-normal intervals (SDNN) was used as the representative HRV value and reported in milliseconds (ms).

All measurements were performed at the same time of day to minimize circadian variations, and participants were instructed to avoid caffeine, heavy meals, or vigorous physical activity for at least 2 hours prior to testing.

Statistical Analysis: Data were analyzed using SPSS version 25.0. Descriptive statistics were computed for all variables. Between-group differences were assessed using independent t-tests for continuous variables and chi-square tests for categorical variables. Repeated measures analysis of variance (ANOVA) was employed to examine changes over time within and between groups. A p-value of less than 0.05 was considered statistically significant.

A total of 60 healthy participants were enrolled in the study, with 30 in the OM meditation group and 30 in the control group. Baseline characteristics were comparable between the two groups (Table 1). The mean age was 42.5 ± 9.3 years in the OM meditation group and 43.1 ± 8.7 years in the control group (p = 0.76). Gender distribution, body mass index (BMI), systolic and diastolic blood pressure (BP), heart rate (HR), and heart rate variability (HRV) were similar between the groups, indicating successful randomization (all p > 0.05).

Table 1: Baseline Characteristics of Participants

Changes in cardiovascular parameters over the 8-week intervention period are summarized in Table 2. In the OM meditation group, systolic BP decreased from 120.8 ± 6.5 mmHg at baseline to 118.2 ± 6.0 mmHg at 4 weeks and further to 116.5 ± 5.7 mmHg at 8 weeks (p < 0.001). Diastolic BP showed a similar reduction, from 78.6 ± 5.0 mmHg at baseline to 76.4 ± 4.7 mmHg at 4 weeks and 75.2 ± 4.5 mmHg at 8 weeks (p < 0.001). Heart rate also declined significantly in the OM meditation group, from 72.4 ± 6.2 bpm at baseline to 70.1 ± 5.8 bpm at 4 weeks and 68.7 ± 5.5 bpm at 8 weeks (p < 0.001). In contrast, the control group demonstrated minimal changes in these parameters over the study period (all p > 0.05).

Table 2: Blood Pressure and Heart Rate at Different Time Points

HRV increased progressively in participants practicing OM meditation (Table 3). The mean HRV was 40.2 ± 5.5 ms at baseline, rising to 43.5 ± 5.7 ms at 4 weeks and 46.8 ± 5.9 ms at 8 weeks (p < 0.001). The control group showed no significant change in HRV during the same period (baseline: 39.8 ± 5.2 ms; 8 weeks: 40.5 ± 5.4 ms; p = 0.27).

Table 3: Heart Rate Variability (HRV) at Different Time Points

Figure 1: Progressive Decline in SBP after OM meditation over time

Figure 2: Progressive Decline in DBP after OM meditation over time

Figure 3: Progressive Decline in HR after OM meditation over time

Figure 4: Improvement in HRV after OM meditation over time

This randomized comparative study in healthy adults found that an 8-week program of OM meditation was associated with modest but statistically significant reductions in systolic and diastolic blood pressure and resting heart rate, alongside increases in heart rate variability (SDNN), compared with a non-intervention control. These findings align with prior evidence that contemplative practices incorporating slow, sonorous breathing and attentional focus can favorably modulate autonomic balance and cardiovascular control. In particular, neuroimaging work during OM chanting has demonstrated deactivation within limbic and thalamic regions implicated in stress reactivity, suggesting a plausible central pathway for vagal enhancement and cardiovascular down-regulation [9].

From a physiological perspective, resonant or slowed breathing can augment baroreflex sensitivity and shift cardiovagal modulation, thereby lowering blood pressure—mechanisms substantiated in controlled laboratory and clinical studies [10,11]. Trials of humming/bee-breath (Bhramari), which resembles the voiced exhalation used in OM practice, show acute increases in high-frequency HRV (parasympathetic activity), even when immediate blood-pressure reductions are not always observed, implying that autonomic benefits may precede or outlast hemodynamic changes [12]. More broadly, yoga-based interventions that integrate breath regulation and meditative focus have yielded small-to-moderate blood-pressure reductions in randomized trials and meta-analyses, consistent with the magnitude and trajectory we observed over 8 weeks [13].

At the same time, the HRV literature warrants a nuanced interpretation. Meta-analytic evidence specific to mindfulness/meditation and vagally mediated HRV (vmHRV) has been mixed, with some analyses reporting insufficient evidence for vmHRV improvement over controls—likely reflecting heterogeneity in populations, protocols, and HRV metrics [14]. By contrast, breathing-focused paradigms tend to show clearer vmHRV gains, supporting the view that dosing and explicit respiratory pacing are key moderators of autonomic outcomes [10]. Our protocol emphasized daily, guided practice and likely promoted a slower, more regular respiratory pattern during and between sessions, which could explain the consistent SDNN increases noted in the OM group.

Clinical implications are twofold. First, in generally healthy adults, OM meditation appears to confer small yet meaningful improvements in resting cardiovascular indices that are risk-relevant over the lifespan. Second, because meditation trials in at-risk or older populations sometimes show null average effects with benefits concentrated in subgroups (e.g., those with elevated baseline diastolic pressure) [15], OM-based programs may be most impactful when targeted to individuals with higher baseline sympathetic tone or preclinical blood-pressure elevations.

Strengths of this study include randomized allocation, standardized instructor-guided sessions, repeated measures across 8 weeks, and inclusion of both hemodynamic and autonomic endpoints. Limitations include a modest sample, reliance on SDNN as the primary HRV measure (without frequency-domain indices), absence of an active control matched for expectancy/attention, and short follow-up. Future trials should incorporate frequency-domain HRV, ambulatory blood pressure, adherence monitoring (e.g., app-logged home practice), and active comparators (e.g., paced breathing alone) to isolate the unique contribution of the mantra component. Longer follow-up will clarify durability and dose–response relationships

The present study demonstrates that 8 weeks of regular OM meditation in healthy adults leads to significant reductions in systolic and diastolic blood pressure, as well as heart rate, along with a notable improvement in heart rate variability. These findings suggest that OM meditation may enhance autonomic cardiovascular regulation and contribute to overall cardiovascular health, even in individuals without preexisting conditions. Incorporating OM meditation into daily routines could serve as a simple, non-pharmacological strategy to promote cardiovascular well-being.

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