European Journal of Cardiovascular Medicine

Cardiovascular health remains a global priority, with elevated resting heart rate (HR) and blood pressure (BP) recognized as independent risk factors for morbidity and mortality[1]. Pharmacological interventions, while effective, often entail side effects and high costs, driving interest in non-pharmacological approaches like yoga [2]. Yoga, an ancient mind-body practice originating in India, has gained empirical support for its cardiovascular benefits through modulation of autonomic nervous system (ANS) activity [3]. Emerging evidence suggests that yoga may reduce sympathetic overactivity while enhancing parasympathetic tone, thereby lowering HR and BP [4].

The numerous studies have examined long-term yoga interventions [5], the acute effects of a single yoga session—particularly using simple, accessible measurement techniques—remain underexplored in the physiological literature. Controlled breathing (Pranayama) has been shown to stimulate vagal activity, thereby reducing HR through increased parasympathetic input [6]. Postural practices (Asanas) may improve baroreflex sensitivity and promote vasodilation, contributing to BP reduction [7]. Furthermore, meditation and relaxation components (e.g., Savasana) are associated with decreased cortisol levels and sympathetic withdrawal [8]. These effects are particularly relevant given the growing burden of stress-related cardiovascular disorders worldwide [9].Despite this mechanistic plausibility, existing studies on acute yoga effects face limitations. Many employs sophisticated instrumentation (e.g., ECG, beat-to-beat BP monitors) [10], limiting applicability in resource-constrained settings. Others lack rigorous control groups [11] or standardized yoga protocols [12]. Additionally, few studies have simultaneously assessed both HR and BP changes using basic clinical tools like manual sphygmomanometer, pulse palpation, which remain the global standard for primary healthcare [13]. This study aimed to investigate the acute effects of a 30-minute yoga session on resting HR and BP compared to a passive control activity, using simple, reproducible measurement techniques.

This randomized controlled trial employed a parallel-group design to compare the acute effects of yoga versus a passive control activity on cardiovascular parameters. A total of 30 healthy adults  (aged 18–45 years) were recruited from Government medical College ,Nandyal  through purposive sampling. The cardiovascular disease, regular yoga practice (>1 session/week), or use of medications affecting HR/BP  subjects were excluded [14]. Participants were randomized into two groups (1:1 allocation) using computer-generated random numbers concealed in opaque envelopes.

The yoga group (n=15) performed a 30-minute standardized session comprising:

• Nadi Shodhana Pranayama(alternate nostril breathing; 5 minutes) to stimulate parasympathetic activity [6],
• Surya Namaskar(sun salutations; 15 minutes) to engage mild aerobic and stretching components [15], and
• Savasana(corpse pose; 10 minutes) to induce relaxation [8].
  The control group (n=15) engaged in quiet reading in a seated position for 30 minutes, an activity previously validated as a neutral comparator for autonomic studies [16]. Both interventions were conducted in a temperature-controlled (24–26°C), quiet environment between 7–9 AM to minimize circadian variability [17].

Resting HR and BP were measured pre- and post-intervention by a blinded investigator. Heart rate was recorded via manual palpation of the radial pulse (counted over 30 seconds × 2) [18], while blood pressure was measured using a calibrated mercury sphygmomanometer (Korotkoff phase I/V for SBP/DBP) [13]. Participants rested supine for 10 minutes prior to baseline measurements to ensure stable hemodynamics [19]. Data were analysed using SPSS v26.0. Normality was confirmed via Shapiro-Wilk tests. Within-group changes were assessed with paired t-tests, and between-group differences via independent t-tests. [20].

The present study examined the acute physiological effects of a 30-minute yoga intervention on cardiovascular parameters in healthy adults.

Baseline Characteristics of Study Participants: Prior to intervention, both groups were statistically comparable across all measured demographic and physiological parameters, ensuring homogeneity between groups at baseline (Table 1).

Table 1: Baseline characteristics of yoga and control groups

p-values derived from independent t-tests for continuous variables and chi-square test for gender distribution. CI = confidence interval.

The study findings are presented through three key tables that systematically demonstrate the effects of yoga on cardiovascular parameters. Table 1 establishes the baseline equivalence between groups, showing no significant differences in demographic or physiological characteristics prior to intervention. The yoga group (n=15) had a mean age of 25.3 years (±4.2) with balanced gender distribution (8 males, 7 females), while the control group (n=15) averaged 26.1 years (±3.8) with 7 males and 8 females. Importantly, baseline cardiovascular measures including resting heart rate (yoga: 72.4±6.1 bpm vs control: 73.2±5.8 bpm), systolic blood pressure (118.3±7.2 vs 120.1±6.9 mmHg), and diastolic blood pressure (76.0±5.4 vs 77.2±4.8 mmHg) showed no statistically significant differences (all p>0.4), as confirmed by narrow 95% confidence intervals crossing zero for all between-group comparisons. This baseline equivalence strengthens the validity of subsequent intervention comparisons.( Fig  1).

Figure 1. The baseline characteristics (mean ± standard deviation) between the Yoga and Control groups. It visually confirms that there are no significant differences at baseline across key parameters like age, BMI, resting heart rate, systolic and diastolic blood pressure.

Within-Group Physiological Changes

Table 2: Pre- and post-intervention changes in cardiovascular parameters

Values represent mean ± SD. Change calculated as post-intervention minus pre-intervention values. p-values from paired t-tests comparing pre-post measurements within each group.

The yoga group demonstrated clinically meaningful reductions across all parameters: heart rate decreased by 6.2±2.1 bpm (p<0.001), systolic blood pressure dropped 5.4±3.2 mmHg (p=0.003), and diastolic blood pressure fell 3.8±2.5 mmHg (p=0.008). These changes represented percentage decreases of 8.6%, 4.6%, and 5.0% respectively. In striking contrast, the control group showed minimal, non-significant variations: heart rate changed by -0.8±1.4 bpm (p=0.42), systolic BP by -0.5±2.0 mmHg (p=0.61), and diastolic BP by -0.5±1.8 mmHg (p=0.55). The consistent statistical significance (p<0.01) in the yoga group versus the null findings in controls strongly suggests the observed effects are intervention-specific rather than artifacts of measurement or time.(Fig 2).

Figure 2. The graph illustrating within-group changes in heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) after the intervention.

Between-Group Comparison of Intervention Effects

Table 3: Comparative analysis of intervention effects between groups

*Between-group differences analysed using independent t-tests. Effect sizes interpreted as: 0.2=small, 0.5=medium, 0.8=large.*

Table 3 provides the crucial between-group comparison of intervention effects. The yoga group showed significantly greater improvements than controls across all measures: the 5.4 bpm greater reduction in heart rate (95% CI: -6.8 to -4.0, p<0.001) corresponded to a large effect size (Cohen's d=1.42).

Blood pressure differences were similarly robust, with yoga producing 4.9 mmHg greater systolic reduction (95% CI: -6.8 to -3.0, p=0.003, d=0.98) and 3.3 mmHg greater diastolic reduction (95% CI: -4.9 to -1.7, p=0.008, d=0.85). The effect sizes, all exceeding conventional thresholds for medium effects (d>0.5), coupled with confidence intervals excluding zero, provide strong evidence for yoga's acute cardiovascular benefits. These findings gain additional clinical relevance when considering that a 5 bpm resting heart rate reduction associates with 17% lower cardiovascular mortality in population studies(Fig 3).

Figure 3 The graph showing the between-group differences in intervention effects for heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP). The error bars represent 95% confidence intervals, and the Cohen’s d effect sizes are annotated above each bar.

The observed reductions in cardiovascular parameters following the yoga intervention carry important clinical implications. The magnitude of heart rate reduction (6.2 bpm) is particularly noteworthy from both physiological and epidemiological perspectives. Population studies have demonstrated that even a modest 5 bpm decrease in resting heart rate is associated with an approximately 17% reduction in cardiovascular mortality risk, suggesting that the acute effects observed in our study may translate to meaningful long-term health benefits if maintained through regular practice. The large effect size (Cohen's d = 1.42) further underscores the clinical relevance of these findings, as it substantially exceeds conventional thresholds for meaningful physiological changes. Importantly, the rapid onset of these effects within just 30 minutes highlights yoga's potential as an accessible intervention for acute stress reduction in both clinical and non-clinical settings[21,22].The blood pressure reductions, while more modest in magnitude, remain clinically significant when viewed in context.

The observed decreases (5.4 mmHg systolic and 3.8 mmHg diastolic) are comparable to the effects seen with first-line antihypertensive medications in normotensive populations, suggesting that yoga may serve as an effective non-pharmacological adjunct for blood pressure management. These findings align with existing literature on other mind-body interventions such as meditation, which have shown similar cardiovascular benefits. The combined effects on both heart rate and blood pressure support yoga's role as a comprehensive intervention for autonomic nervous system regulation and cardiovascular risk reduction.[23].

The present study provides compelling evidence that a single 30-minute yoga session significantly reduces resting heart rate (HR) and blood pressure (BP) in healthy adults compared to passive control activities. These findings contribute meaningfully to the growing body of literature on yoga's cardiovascular benefits while addressing several gaps in existing research.

Physiological Mechanisms and Autonomic Modulation

The observed reduction in HR (6.2 bpm) strongly suggests acute enhancement of parasympathetic nervous system activity, likely mediated through slow, controlled breathing during Pranayama [6]. This aligns with prior work by Telles et al. [24], who documented increased high-frequency HRV - a marker of vagal tone - following Nadi Shodhana Pranayama. However, our study extends these findings by demonstrating that such autonomic shifts translate to clinically measurable HR reductions using only manual pulse palpation, making the assessment feasible in resource-limited settings. The concurrent BP reductions (5.4/3.8 mmHg) may reflect both central autonomic effects and peripheral vascular changes. Previous research has shown that yoga postures like Surya Namaskar can improve baroreflex sensitivity [25] and promote endothelial function [31], potentially explaining our BP findings. Notably, the effect sizes (Cohen's d: HR=1.42; SBP=0.98) substantially exceed those reported for acute aerobic exercise (typically d=0.3-0.6) [26], suggesting yoga's unique multi-system regulatory capacity.

Clinical Implications for Preventive Cardiology

The magnitude of HR reduction holds clinical significance. Epidemiological data consistently show that a 5 bpm lower resting HR associates with 17% reduced cardiovascular mortality [21].

Our demonstration that such reduction can be achieved within 30 minutes suggests yoga's potential for acute stress mitigation in high-risk situations (e.g., pre-surgical settings or stress-induced arrhythmias). For BP, while our reductions appear modest compared to antihypertensive drugs, they match the 4-5 mmHg thresholds shown to reduce stroke risk by 20% in meta-analyses [27]. This supports yoga's role in:

• Prehypertension management, where early intervention may prevent medication need [28]
• Adjunct therapyfor medicated patients with residual hypertension [22]
• Workplace wellness programstargeting stress-related cardiovascular risk [32]

Our results both confirm and extend existing literature. While Cramer et al. [3] demonstrated yoga's long-term BP-lowering effects, and Tyagi et al. [24] documented autonomic changes, few studies have examined acute effects using basic clinical tools. The HR reduction in our study (6.2 bpm) exceeds values from comparable meditation research (typically 2-4 bpm) [23], likely due to yoga's combined physical postural, respiratory, and relaxation components. This multi-modal advantage was hinted at in a 2022 meta-analysis [29], but our controlled design provides stronger causal evidence. Interestingly, our BP findings closely match Hagins et al.'s [5] systematic review estimates for single sessions, despite their inclusion of studies requiring advanced monitoring equipment. Our study represents several important methodological advancements in yoga research.

Unlike many previous investigations that relied on sophisticated equipment, we deliberately employed only manual blood pressure measurement and pulse palpation techniques [13], thereby demonstrating that yoga's cardiovascular effects can be reliably detected using basic clinical tools available even in resource-limited settings - a crucial consideration for global health applications. Furthermore, our design significantly improves upon earlier mind-body studies by incorporating an active control group [11], which helps distinguish yoga-specific effects from general time or measurement-related influences. Another key advancement lies in our comprehensive reporting of effect sizes (Cohen's d values ranging 0.85-1.42), whereas most prior yoga studies limited their reporting to p-values alone [12], providing clinicians with more meaningful metrics for evaluating the practical significance of our findings. While these methodological strengths enhance our confidence in the results, several limitations must be acknowledged. Additionally, our focus on healthy young adults means the generalizability of findings to clinical populations such as hypertensive or elderly individuals requires further verification [33]. These limitations naturally point to important directions for future research. Longitudinal studies tracking the cumulative effects of daily yoga practice over several weeks would help bridge the gap between our acute findings and the established literature on long-term benefits. Incorporating ambulatory blood pressure monitoring [19] could provide valuable insights into the duration of yoga's cardiovascular effects beyond the immediate post-session period. Furthermore, including measures of inflammatory markers [34] would help explore additional physiological pathways through which yoga may confer its benefits.

Our findings demonstrate that even a single brief yoga session can induce clinically meaningful improvements in heart rate and blood pressure, likely through autonomic nervous system modulation. Future research should focus on optimizing yoga protocols for specific population subgroups and investigating strategies to enhance long-term adherence, thereby maximizing the potential public health impact of this ancient practice.

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