Effect of Surya Namaskar on Autonomic Status and Serum Cortisol Levels in Male Medical Students: A Longitudinal Study

Abstract

Introduction: Stress is an unavoidable and ongoing phenomenon in human life that affects physiological processes in the body. Regular practice of Surya Namaskar, a yogic exercise, has been shown to improve autonomic functions by reducing sympathetic activity, thereby decreasing stress levels and improving cortisol levels. Aim: To evaluate the effects of Surya Namaskar on autonomic status and serum cortisol levels among medical students. in the Department of Physiology at the Faculty of Medicine and Health Sciences, SGT University, Gurugram, Haryana, India. The study duration was three months, from November 2021 to January 2022. A total of 30 male medical students, aged between 18 and 21 years, were included in the study. Blood samples for cortisol estimation were collected before the start of the study and after six weeks of regular yogic practice. Parameters such as mean pulse rate, Blood Pressure (BP), and Low Frequency to High Frequency (LF/HF) ratio were also studied during these two time points. Statistical analysis of Heart Rate Variability (HRV) parameters, including Standard deviation of the N-N interval (SDNN), mean Heart Rate (HR), and pNN50, was performed using Analysis of Variance (ANOVA) at baseline and after six weeks. Comparison of serum cortisol levels within the groups was done using paired t-tests. Results: The mean age of the study participants was 20.37 years. Comparison of HRV frequency domain parameters (LF, HF, and LF/HF ratio) at baseline, day one, and after six weeks of yogic practice showed statistically significant variations in LF/ HF ratio after six weeks (p-value=0.001). Baseline serum cortisol levels compared to levels after six weeks of yogic practice were also found to be statistically significant (p<0.001). Conclusion: There is a positive association between cortisol levels and autonomic parameters, as evidenced by the results of the autonomic battery of tests. Incorporating yogic interventions into one’s lifestyle helps reduce sympathetic parameters and shift the balance towards parasympathetic dominance.