Comparison of Heart Rate Variability during Physical and Mental Stress in Type 'A' and Type 'B' personality: An Interventional Study
Abstract
Stress is the gift of today's modernization. It may influence autonomic nervous system (ANS). It may reflect on Heart Rate Variability (HRV). Personality may affect the stress level effect on ANS. So this comparative interventional study was conducted to compare HRV response of physical and mental stress in both type of personality (type 'A' and type 'B'). This study was conducted of 30 type 'A' personality and 30 type 'B' personality subjects. Baseline HRV was recorded then mental stress is given and HRV was again recorded after 5 minutes. After 5 minutes physical stress was given and HRV was again recorded after 5 minutes. Mean change in HRV was compared in both the personality after mental and physical stress. Significance of this mean difference was ascertain with the help of unpaired 't' test. It was found that In Physical stress, all the parameters of HRV are significantly reduces in type 'A' personality than type 'B' personality except parasympathetic activity which was significantly less in type 'B' personality than type 'A'. In mental stress, there was no significant difference in all the parameters of HRV in type 'A' personality than type 'B' personality except in heart rate which was significantly reduced in type 'B' personality than type 'A'. The present study concluded that the mental stress should be avoided by both personality subjects, as it increases the sympathetic and reduces the parasympathetic outflow. Physical stress is beneficial to type 'A' personality subjects.
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Introduction
Stress is the body’s response to counteract the challenges that influences our autonomic nervous system (ANS). The ANS consist of sympathetic and parasympathetic nervous system and their activity are reflected by heart rate variability (HRV). Fluctuations in heart rate above 0.03 Hz reflect autonomic modulation of sinoatrial node activity. The low frequency (LH: 0.03-0.15Hz) and high frequency (HF: 0.15-0.80Hz) power represent sympathetic and parasympathetic nervous system activity respectively and LF: HF ratio has been used to quantify the sympathovagal balance.1 A link between work stress and disease related to the sympathetic and parasympathetic system. HRV analysis provide state of body and mind, the LH, HF and LF: HF ratio adopted as a marker of stress in various studies1,2,3 Research indicate that type of personality also influences the subjective response to stress. Coronary heart disease is more common in individuals subjected to chronic stress. The Type ‘A’ personalities are more prone to coronary disease, more risk for heart attacks, while Type ‘B’ personality has lower stress levels.4
The previous studies focus on either physical or mental stress only, the relation is not established between HRV and mental and physical stress of an individual of different personalities.
Conclusion
The present study concluded that the mental stress should be avoided by both personality subjects, as it increases the sympathetic and reduces the parasympathetic outflow. Physical stress is beneficial to type 'A' personality subjects.