Heart Rate Variability and Stress Levels among Undergraduate Medical Students

Harni E et al | DOI: 10.65188/nurexus.1091

Page 1

Journal of MedVerse Research & Practice

ISSN: 3107-4278

Heart Rate Variability and Stress Levels among Undergraduate Medical

Students

E Harni

, L Lakshmi

Postgraduate, Professor & HOD

Department Of Physiology, Mediciti Institute of Medical Sciences, Ghanpur

Email ID: harni.ovi@gmail.Com

Submission Date: 03.06.2026

Accepted Date:15.07.2026

Published Date: 31.07.2026

DOI: 10.65188/nurexus.1091

article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted

use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

Abstract

Background: Medical students are frequently exposed to academic, emotional, and psychological stress, which can

adversely affect autonomic nervous system function. Heart Rate Variability (HRV) is a reliable, non-invasive

indicator of autonomic balance and can be used to objectively assess physiological responses to stress. This study

aimed to evaluate the association between heart rate variability and perceived stress among undergraduate medical

students.

Materials and Methods: A cross-sectional observational study was conducted among 150 undergraduate medical

students in the Department of Physiology, Mediciti Institute of Medical Sciences, Ghanpur. Perceived stress was

assessed using the Perceived Stress Scale (PSS-10), and HRV was recorded under standardized resting conditions.

Time-domain parameters (SDNN and RMSSD) and the frequency-domain parameter (LF/HF ratio) were analyzed.

Statistical analysis was performed using SPSS version 25.0, with p < 0.05 considered statistically significant.

Results: The mean age of the participants was 20.8 ± 1.5 years, and 54.0% were females. Moderate stress was

observed in 62.0% of students, while 24.0% experienced high stress. SDNN and RMSSD decreased significantly

with increasing stress levels, whereas the LF/HF ratio increased significantly (p < 0.001). Perceived stress showed a

significant negative correlation with SDNN (r = −0.42) and RMSSD (r = −0.39), and a positive correlation with the

LF/HF ratio (r = 0.36, p = 0.002).

Conclusion: Higher perceived stress was significantly associated with reduced heart rate variability, indicating

impaired autonomic function among undergraduate medical students. Early stress identification and targeted

interventions may improve autonomic health and psychological well-being.

Keywords

Heart Rate Variability; Stress; Perceived Stress Scale; SDNN; RMSSD; LF/HF Ratio; Undergraduate Medical

Students; Autonomic Nervous System.

Introduction

Medical education is widely recognized as one of the most demanding professional training programs,

requiring students to cope with intensive academic schedules, frequent examinations, clinical

responsibilities, and continuous assessment. These academic commitments are often accompanied by

inadequate sleep, limited leisure time, social adjustments, and concerns regarding future career prospects.

The cumulative effect of these factors places undergraduate medical students at a greater risk of

experiencing psychological stress than many of their age-matched peers. Although a certain level of stress

may enhance motivation and learning, persistent or excessive stress can adversely affect emotional well-

being, academic performance, interpersonal relationships, and physical health [1,2].

ORIGINAL ARTICLE

Harni E et al | DOI: 10.65188/nurexus.1091

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Psychological stress produces measurable physiological changes through activation of the autonomic

nervous system and the hypothalamic-pituitary-adrenal axis. During stressful situations, sympathetic

nervous system activity increases while parasympathetic activity decreases, enabling the body to respond

to immediate demands. However, sustained sympathetic activation without adequate recovery may lead to

autonomic imbalance, contributing to fatigue, impaired concentration, anxiety, depression, hypertension,

metabolic disturbances, and increased cardiovascular risk [3,4]. Therefore, identifying objective indicators

of stress has become an important area of research in student health. Heart rate variability (HRV) is a non-

invasive and reliable measure of autonomic nervous system function that reflects the variation in time

intervals between consecutive heartbeats. It provides valuable information regarding the balance between

sympathetic and parasympathetic activity. Individuals with higher HRV generally demonstrate better

autonomic adaptability and greater resilience to physical and psychological stress, whereas lower HRV is

indicative of reduced vagal tone, impaired autonomic regulation, and diminished physiological flexibility

[3-5]. Previous studies have reported a consistent association between chronic psychological stress and

reduced HRV, suggesting that autonomic dysfunction may develop even in otherwise healthy young adults

exposed to prolonged stress [5,6].

Medical students constitute an ideal population for evaluating this relationship because they are routinely

exposed to multiple academic and psychosocial stressors throughout their training. While perceived stress

is commonly assessed using validated self-report questionnaires, HRV offers an objective physiological

assessment that complements subjective findings. Examining both parameters together can provide a more

comprehensive understanding of stress-related autonomic changes and help identify students who may

benefit from early support [6,7]. Assessing the relationship between heart rate variability and perceived

stress among undergraduate medical students may contribute to the early detection of stress-related

autonomic dysfunction before clinically significant health problems develop. The findings may support the

implementation of evidence-based interventions such as stress management programs, mindfulness

training, regular physical activity, and psychological counseling to improve students' mental well-being and

autonomic health. Such information may also assist educational institutions in developing strategies that

promote resilience, improve learning environments, and enhance the overall health and academic success

of future healthcare professionals [7,8].

Materials & Methods

Study Design

This cross-sectional observational study was conducted to assess the relationship between perceived stress

and heart rate variability (HRV) among undergraduate medical students.

Study Setting and Duration

The study was conducted in the Department of Physiology, Mediciti Institute of Medical Sciences,

Ghanpur, during the predefined study period. Institutional Ethics Committee approval was obtained prior

to the commencement of the study, and all procedures were carried out in accordance with the ethical

principles governing biomedical research involving human participants.

Study Population

The study population consisted of undergraduate medical students enrolled at Mediciti Institute of Medical

Sciences. A total of 150 students who fulfilled the eligibility criteria and voluntarily agreed to participate

were included after obtaining written informed consent.

Sample Size

A total of 150 undergraduate medical students were included in the study. The sample size was determined

based on the number of eligible students available during the study period who met the inclusion criteria

and consented to participate.

Harni E et al | DOI: 10.65188/nurexus.1091

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Inclusion Criteria

Apparently healthy undergraduate medical students aged between 18 and 25 years who were willing to

participate in the study and provided written informed consent were included.

Exclusion Criteria

Students with a history of cardiovascular disease, hypertension, diabetes mellitus, psychiatric illness,

neurological disorders, chronic systemic diseases, acute illness at the time of data collection, or those

receiving medications known to influence autonomic nervous system function, such as beta-blockers,

antidepressants, or antiarrhythmic drugs, were excluded from the study.

Data Collection Tool

Eligible participants were recruited after explaining the objectives and procedures of the study and

obtaining written informed consent. Demographic information, including age, sex, and year of study, was

collected using a structured questionnaire. Perceived stress was assessed using the validated Perceived

Stress Scale-10 (PSS-10), which measures the degree to which individuals perceive stressful situations

during the preceding month. Heart rate variability was recorded under standardized resting conditions in a

quiet, temperature-controlled environment using a validated HRV recording system. Participants were

instructed to avoid caffeine, alcohol, smoking, strenuous physical activity, and heavy meals before HRV

assessment to minimize factors influencing autonomic function. Time-domain HRV parameters, including

the standard deviation of normal-to-normal intervals (SDNN) and the root mean square of successive

differences (RMSSD), as well as frequency-domain parameters including low-frequency (LF) power, high-

frequency (HF) power, and the LF/HF ratio, were recorded to assess autonomic nervous system activity.

Ethical Considerations

The study protocol was reviewed and approved by the Institutional Ethics Committee of Mediciti Institute

of Medical Sciences, Ghanpur. Written informed consent was obtained from all participants before

enrolment. Participant confidentiality and anonymity were maintained throughout the study by assigning

unique identification numbers and ensuring that all collected information was used solely for research

purposes.

Statistical Analysis

The collected data were entered into Microsoft Excel for coding and cleaning before being analyzed using

IBM Statistical Package for the Social Sciences (SPSS) software version 25.0. Continuous variables were

expressed as mean ± standard deviation, while categorical variables were presented as frequencies and

percentages. Pearson's correlation coefficient was used to assess the relationship between perceived stress

scores and heart rate variability parameters. Appropriate comparative statistical tests were applied based on

the distribution of the data, and a p-value of less than 0.05 was considered statistically significant.

Result

Table 1. Baseline Characteristics of the Study Participants (n = 150)

Variable

Value

Age (years), Mean ± SD

Male, n (%)

69 (46.0)

Female, n (%)

81 (54.0)

The study included 150 undergraduate medical students with a mean age of 20.8 ± 1.5 years. Female

participants (54.0%) slightly outnumbered males (46.0%).

Table 2. Distribution of Stress Levels (PSS-10)

Stress Level

Frequency (n)

Percentage (%)

Low Stress

14.0

Moderate Stress

62.0

High Stress

24.0

Harni E et al | DOI: 10.65188/nurexus.1091

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Most participants (62.0%) experienced moderate stress, while 24.0% reported high stress, indicating that

stress is common among undergraduate medical students.

Table 3. Comparison of HRV Parameters According to Stress Levels

HRV Parameter

Low Stress

Moderate Stress

High Stress

SDNN (ms)

58.6 ± 9.4

49.7 ± 8.6

39.8 ± 7.5

RMSSD (ms)

46.2 ± 7.8

38.5 ± 6.9

30.4 ± 5.8

LF/HF Ratio

1.42 ± 0.34

1.89 ± 0.42

2.63 ± 0.58

Increasing stress levels were associated with a significant decrease in SDNN and RMSSD and a

significant increase in the LF/HF ratio (p < 0.001), indicating reduced parasympathetic activity and

increased sympathetic dominance.

Table 4. Correlation Between Perceived Stress and HRV Parameters

Variable

Correlation (r)

p-value

PSS vs SDNN

-0.42

<0.001

PSS vs RMSSD

-0.39

<0.001

PSS vs LF/HF Ratio

0.36

0.002

Perceived stress showed a moderate negative correlation with SDNN and RMSSD, and a positive

correlation with the LF/HF ratio, demonstrating that higher stress is associated with impaired autonomic

function. Table 5. Summary of Major Findings

Finding

Result

Mean Age

20.8 ± 1.5 years

Moderate Stress

62.0%

High Stress

24.0%

Significant Reduction in SDNN & RMSSD

Yes (p < 0.001)

Significant Increase in LF/HF Ratio

Yes (p < 0.001)

Significant Correlation Between Stress and HRV

Yes (p < 0.05)

The study demonstrated that higher perceived stress was significantly associated with reduced heart rate

variability, suggesting altered autonomic balance among undergraduate medical students. These findings

highlight the importance of stress management strategies to improve students' cardiovascular and

psychological well-being.

Discussion

Perceived stress is increasingly recognized as a significant determinant of autonomic nervous system

function among medical students because of prolonged academic demands, emotional stressors, and

competitive learning environments. In the present study, students with higher perceived stress demonstrated

significantly lower SDNN and RMSSD values along with a significantly higher LF/HF ratio, indicating

reduced parasympathetic activity and increased sympathetic predominance. A significant negative

correlation was observed between Perceived Stress Scale (PSS-10) scores and heart rate variability (HRV)

parameters (p < 0.001), suggesting that increasing psychological stress adversely affects autonomic

regulation.

Yoo et al. (2021) demonstrated that HRV is a useful objective marker for assessing stress among medical

students and reported that alterations in autonomic balance were associated with increased academic stress

during clinical training [1]. Similarly, Miller et al. (2022) observed that students with higher perceived

stress scores had significantly reduced HRV parameters, reflecting impaired parasympathetic activity and

altered sympathovagal balance [2]. These findings are consistent with the present study, where higher stress

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levels were associated with significantly lower SDNN and RMSSD values. LeBlanc et al. (2025) further

demonstrated that HRV-derived parameters correlate closely with physiological and psychological

measures of stress among healthcare learners and suggested that HRV can serve as a reliable, non-invasive

biomarker for objective stress assessment [3]. Likewise, Kim et al. (2022) reported that medical students

with elevated stress exhibited significantly reduced HRV indices, indicating autonomic dysfunction

secondary to chronic psychological stress [4]. The present study similarly demonstrated a significant

inverse relationship between perceived stress scores and HRV parameters, reinforcing the value of HRV in

stress evaluation.

Shaffer et al. (2020) emphasized that HRV represents a sensitive physiological indicator of autonomic

nervous system regulation and highlighted the importance of standardized HRV assessment in stress

research [9]. McEwen (2020) explained that chronic psychological stress activates the hypothalamic-

pituitary-adrenal axis and sympathetic nervous system, leading to sustained autonomic imbalance and

adverse cardiovascular consequences [10]. These mechanisms support the present findings, where

increased perceived stress was associated with reduced parasympathetic modulation and elevated

sympathetic activity. Taelman et al. (2021) demonstrated that mental stress significantly reduces HRV by

increasing sympathetic activation and suppressing vagal activity, thereby altering autonomic balance [11].

Similarly, Kim et al. (2023) reported that university students with higher psychological stress had

significantly reduced HRV indices, confirming the relationship between stress and autonomic dysfunction

[12]. These observations closely correspond with the present study, which identified lower SDNN and

RMSSD values and higher LF/HF ratios among students experiencing greater perceived stress.

Amin et al. (2025) reported that HRV effectively identifies stress among undergraduate students, with

higher stress levels associated with reduced HRV and increased LF/HF ratio, indicating sympathetic

predominance [14]. Malik and Camm (2021) highlighted the clinical utility of HRV as a reliable measure

of autonomic nervous system function and emphasized its application in monitoring stress-related

physiological changes [15]. Raj (2022) further stated that reduced HRV is associated with impaired

autonomic regulation and may predispose individuals to future cardiovascular morbidity if persistent stress

remains unaddressed [16]. Overall, the findings of the present study are consistent with previous literature

demonstrating that increased perceived stress is associated with significant autonomic imbalance

characterized by reduced parasympathetic activity and increased sympathetic dominance. These findings

support the incorporation of stress management strategies, psychological counselling, mindfulness

practices, relaxation techniques, and lifestyle modifications within medical education to improve students'

psychological well-being and maintain healthy autonomic nervous system function.

Strengths

This study employed a validated Perceived Stress Scale (PSS-10) together with standardized heart rate

variability assessment under controlled conditions, providing an objective evaluation of autonomic nervous

system function in relation to perceived stress among medical students. The use of both time-domain and

frequency-domain HRV parameters enhanced the comprehensiveness of autonomic assessment.

Limitations

The cross-sectional design precludes the establishment of a causal relationship between perceived stress

and heart rate variability. In addition, the study was conducted in a single medical institution with a

relatively limited sample size, which may restrict the generalizability of the findings. Factors such as sleep

quality, dietary habits, and recent academic workload, which could influence stress levels and HRV, were

not comprehensively evaluated.

Conclusion

Higher perceived stress was significantly associated with reduced heart rate variability, reflected by lower

Harni E et al | DOI: 10.65188/nurexus.1091

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SDNN and RMSSD and a higher LF/HF ratio. These findings suggest that stress adversely affects

autonomic function among undergraduate medical students, emphasizing the need for early stress

management strategies.

Declaration

Conflict of Interest: The authors declare that they have no competing interests or conflicts of interest

related to this work.

Funding: Nil

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