Effect of Smartphone Use-induced Mental Stress on Cardiovascular Autonomic Parameters in Medical Students: A Cross-sectional Analytical Study

Abstract

Background: Smartphones have become an essential component of medical education and social communication. However, prolonged and problematic smartphone use has been associated with psychological stress, sleep disturbance, and other adverse behavioral outcomes. Psychological stress can influence autonomic cardiovascular regulation, which can be assessed non-invasively using heart rate variability (HRV). Aim: The aim of the study was to evaluate the association between smartphone use, perceived psychological stress, and cardiovascular autonomic parameters among medical students. Materials and Methods: A cross-sectional analytical study was designed among undergraduate medical students aged 18–25 years. Daily smartphone exposure was assessed using objectively recorded smartphone screen time. Perceived psychological stress was assessed using the 10-item perceived stress scale (PSS-10). Cardiovascular autonomic function was evaluated using short-term electrocardiographic HRV analysis, including standard deviation of normal-to-normal intervals (SDNN), root mean square of successive differences (RMSSD), percentage of successive NN intervals, low-frequency (LF) power, high-frequency (HF) power, and LF/HF ratio. Resting heart rate and blood pressure were also recorded. Participants were categorized according to daily smartphone-use duration. Correlations and multivariable regression analyses were planned to assess the independent association between smartphone exposure, perceived stress, and HRV. Results: In this study, we included 200 medical students; mean smartphone use was 5.7 ± 2.1 h/day, and mean PSS-10 score was 20.8 ± 6.2. Students with >6 h/day of smartphone use demonstrated higher mean PSS scores and lower RMSSD and SDNN compared with students using smartphones <4 h/day. Mean RMSSD was 28.4 ± 9.7 ms in the high-use group compared with 35.8 ± 11.2 ms in the low-use group. The mean LF/HF ratio was 2.31 ± 0.91 and 1.74 ± 0.72, respectively. Smartphone-use duration showed a positive correlation with PSS score and an inverse correlation with RMSSD. PSS score was independently associated with RMSSD after adjustment for age, sex, body mass index, sleep duration, caffeine intake, and physical activity. Conclusion: Higher smartphone exposure may be associated with increased perceived psychological stress and altered cardiovascular autonomic modulation among medical students. However, due to the cross-sectional design, these associations should not be interpreted as evidence of causality. Prospective and interventional studies are required to determine whether reducing problematic smartphone use improves psychological stress and autonomic cardiovascular function.