Effect of Physical Stress on Heart Rate Variability (HRV) in Subjects of Type 'A' and Type 'B' Personality

Background: Stress is defined as an individual's inability to cope with a changed situation. Stress can be either mental or physical, or both. Stress up to an optimal level is required to achieve the goal, but prolonged stress can lead to illness. Individuals' ability to cope with stress varies according to their personalities. The stress response also depends on individuals’ characteristics such as age, physical well-being, personality, etc. Stress has an impact on our autonomic functions, which can be measured in terms of heart rate variability (HRV). As a result, the purpose of this study was to compare the effects of physical stress in subjects with Type 'A' and Type 'B' personalities.

Methodology: For this study, 30 participants with Type 'A' personalities and 30 people with Type 'B' personalities between the ageof 18 and 30 were recruited. HRV was measured in all participants during rest (baseline) and after physical stress for five minutes for short-term analysis. Physical stress was applied in the form of 45-degree shoulder abduction of one arm with maximum extension.

Results: Type 'A' personality subjects had higher baseline heart rates than Type 'B' personality subjects. When the physical stress was applied, the sympathetic parameters (LF, LF: HF ratio) was decreased and the parasympathetic parameter (HF) was increased in Type 'A' whereas in Type 'B' personality subjects parasympathetic parameter (HF) was increased and sympathetic parameters (LF) was decreased.

Conclusions: Physical stress is beneficial to Type 'A' personality subjects because it increases parasympathetic activity, whereas Type 'B' personality subjects are unable to cope with physical stress because it increases sympathetic activity.