Hostility, gender, and cardiac autonomic control.

Area of Science:

• Cardiology
• Psychophysiology
• Autonomic Nervous System Research

Background:

• Hostility is a known risk factor for coronary artery disease (CAD), but the underlying mechanisms are not fully understood.
• A psychophysiological model proposes that autonomic nervous system dysfunction mediates the link between psychological traits and CAD.
• Stressors are known to reduce high-frequency (HF) heart period variability, an indicator of cardiac vagal modulation.

Purpose of the Study:

• To investigate the relationship between hostility and cardiac autonomic function.
• To test the hypothesis that hostility is inversely associated with reductions in HF power in response to psychological and orthostatic challenges.
• To explore potential gender differences in the association between hostility and autonomic responses.

Main Methods:

• 96 subjects were screened for hostility using the Cook-Medley Hostility Scale.
• 15 men and 15 women with a wide range of hostility scores participated in laboratory sessions.
• Continuous electrocardiographic, blood pressure, and respiration monitoring were used during assessments of reactivity to mental and orthostatic stressors.

Main Results:

• Hostility was inversely related to changes in heart period variability in response to mental stressors, as predicted.
• No significant relationship was found between hostility and responses to orthostatic (tilt) challenges.
• Preliminary data suggested a potential influence of gender on these observed relationships.

Conclusions:

• Hostility significantly influences vagal modulation of the cardiovascular system.
• Altered autonomic control, specifically reduced vagal modulation during stress, is a likely pathogenic mechanism linking hostility to CAD.
• These findings support the psychophysiological model and highlight the importance of psychological factors in cardiovascular health.