European Journal of Biomedical and Pharmaceutical Sciences

HEART RATE VARIABILITY TO ACUTE MILD PHYSICAL STRESS

Pandey K. R.*, Agrawal K., Pandey D. R., Paudel B. H. and Khadka R.

ABSTRACT

Introduction: Physical stress produces changes in the cardio-autonomic activity which can be assessed by a non-invasive and a reliable tool, Heart Rate Variability (HRV). In our study, we tried to explore whether handgrip at 12.5% MVC could produce any significant change in HRV measures or not. Materials and Method: A cross-sectional study was conducted on 18-26 yrs apparently healthy health sciences students (30 males and 30 females) with BMI <25 Kg/m2 at BPKIHS, Dharan, Nepal. Their 5 min resting HRV was recorded. A minimal physical stress of 12.5% MVC on isometric handgrip was imposed for next 5 min. HRV recording was done during the stress period as well as 1.5 minutes later the release of stress. The data were expressed in median and interquartile range. For within the group comparison (resting, physical exercise and recovery) Friedman test followed by multiple comparison was done, considering statistical significance at p<0.05. Results: During handgrip, RMSSD and pNN50 decreased significantly in males and in females RMSSD, pNN50, HF power and HF (nu) decreased significantly whereas, LF (nu) and LF/HF ratio increased significantly. During recovery from stress, SDNN, RMSSD, pNN50, LF power and TP increased significantly in males. In females, RMSSD, pNN50, HF power and HF (nu) increased significantly but LF (nu) and LF/HF ratio decreased significantly. On comparing resting with recovery, SDNN, LF (nu) and TP increased significantly however, HF (nu) decreased significantly in males whereas, only SDNN increased significantly in females. Conclusion: Minimal degree of physical stress imparted parasympathetic withdrawal and sympathetic activation in females whereas in males there was only parasympathetic withdrawal. Thus, indicating decreased parasympathetic reserve in young females. But females recovered better from this physical stress than males.

Keywords: HRV, Handgrip, Recovery from physical stress, Gender.