European Journal of Cardiovascular Medicine

Hypertension remains one of the leading causes of cardiovascular morbidity and mortality worldwide (1). In India, its prevalence is steadily rising due to lifestyle changes, urbanization, and genetic susceptibility. Family history is a recognized predisposing factor, reflecting inherited autonomic tendencies that may predispose individuals to hypertension later in life (2). Heart rate variability (HRV) is a non-invasive measure of autonomic nervous system balance, with reduced variability indicating sympathetic predominance and potential cardiovascular risk (3). Identifying autonomic alterations in normotensive individuals with a hypertensive family background could provide valuable insight into early preventive strategies. Recent studies have emphasized that early changes in autonomic function can occur long before the clinical manifestation of hypertension. Monitoring HRV provides a sensitive and practical approach to detect subclinical autonomic dysfunction, even in seemingly healthy individuals (4-6). Such early detection may enable timely lifestyle interventions—such as physical activity, dietary control, and stress management—to prevent or delay the onset of hypertension (7). Evaluating HRV differences in young adults based on their family history could thus serve as a crucial step in understanding genetic and environmental influences on cardiovascular regulation. This study aimed to assess HRV parameters in young adults with and without a parental history of hypertension and to determine if significant differences exist in autonomic function between the two groups

Study Design: Cross-sectional study conducted in the Department of Physiology, SRMS Bareilly.

Study Population: Healthy young adults aged 18–25 years.

Grouping:

• Group 1: Normotensive subjects with normotensive parents.
• Group 2: Normotensive subjects with hypertensive parents.

Inclusion Criteria:

• Healthy young adults aged 18–25 years.
• Both parents either normotensive or hypertensive.

Exclusion Criteria:

• History of systemic illness or cardiovascular disease.
• Athletes or individuals with abnormal physical training.
• Mental health problems that could affect HRV.

Heart Rate Variability (HRV) Assessment:

All subjects were instructed to take 15 minutes of rest before recording. A continuous Lead-II ECG was then recorded for 20 minutes and analyzed using the Lab Chart ECG analysis module (Power Lab 26T-ML4856, AD Instruments) at a sampling frequency of 1 kHz. The last 5 minutes of artifact-free ECG data were used for analysis of short-term frequency-domain variable with the HRV module of Lab Chart Pro software.

Frequency-Domain Parameters:
The following parameters were obtained in absolute values (ms²):

• Total Power (TP: 0–0.40 Hz): Represents overall autonomic activity.
• Very Low Frequency (VLF: <0.04 Hz): Reflects parasympathetic activity.
• Low Frequency (LF: 0.04–0.15 Hz): Reflects sympathetic control with parasympathetic modulation.
• High Frequency (HF: 0.15–0.40 Hz): Represents parasympathetic activity.

LF and HF components were also expressed in normalized units, and the LF/HF ratio was calculated as an indicator of the balance between sympathetic and parasympathetic activity.

HRV Parameters Measured:

• Very Low Frequency (VLF)
• Low Frequency (LF)
• High Frequency (HF)
• LF/HF ratio

Statistical Analysis:
Data were expressed as mean ± SD and analyzed using the independent t-test. A p-value < 0.05 was considered statistically significant.

While VLF, LF, and HF components did not show a statistically significant difference between the two groups, the LF/HF ratio was significantly higher in offspring of hypertensive parents. This indicates a shift toward sympathetic dominance and reduced parasympathetic modulation

The findings of this study bolster the hypothesis that young adults with a hypertensive family history exhibit altered autonomic regulation even before the onset of clinically detectable hypertension. As in our cohort—where the LF/HF ratio was significantly elevated among offspring of hypertensive parents—this suggests a shift toward sympathetic dominance and diminished parasympathetic activity. Our results align with previous research: for example, Muralikrishnan et al. (2011) observed young normotensive males with hypertensive parents showed increased LF and reduced HF components of HRV, reflecting early sympathovagal imbalance (8).

Moreover, more recent work highlights the genetic underpinning of autonomic and blood pressure regulation. Tegegne et al. (2020) demonstrated that genetic factors significantly contribute to HRV variance and blood pressure measures across populations, pointing to a heritable basis for autonomic dysregulation in individuals with family history of hypertension (9). Lifestyle factors also appear to modify this risk. In a study by Santa-Rosa et al. (2020), offspring of hypertensive parents who engaged in an active lifestyle exhibited better HRV parameters (lower LF/HF ratio) compared to their sedentary counterparts, indicating that early lifestyle intervention may mitigate autonomic imbalance in this high-risk group (10).

Taken together, our results suggest that even in apparently healthy, normotensive young adults, a parental history of hypertension is associated with subclinical autonomic changes. The elevated LF/HF ratio in our study indicates rising sympathetic predominance, a known risk factor for future cardiovascular disease. Consequently, these findings emphasize the value of early screening of HRV in offspring of hypertensive parents and reinforce the role of targeted lifestyle interventions—such as increased physical activity, stress management, and dietary control—to reduce long-term cardiovascular risk.

Finally, while our study focussed on frequency-domain HRV metrics, emerging research indicates the added prognostic value of nonlinear HRV measures in predicting cardiovascular risk among high-risk populations. Incorporating these advanced metrics in future studies may further refine risk stratification and preventive interventions.

This study demonstrated that normotensive young adults with a family history of hypertension have higher LF/HF ratios compared to those without such history, suggesting early sympathetic predominance. Early screening of HRV in this population can serve as a valuable tool for preventive health strategies.

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