Low Anxiety Males Display Higher Degree of Salt Sensitivity, Increased Autonomic Reactivity, and Higher Defensiveness

BACKGROUND: Psychological parameters such as heightened anxiety and defensiveness are associated with increased cardiovascular morbidity and mortality. Autonomic dysfunction is considered to be an important pathogenetic pathway. Little research has been done regarding potential links between emotional factors and salt sensitivity. The aim of the present study was to determine whether subjects with different levels of trait anxiety differ in the degree of salt sensitivity and autonomic reactivity to a mental stress task. METHODS: Seventy-two young normotensive men were phenotyped for salt sensitivity and underwent a standardized mental stress test and psychological assessment. According to their trait anxiety test scores, they were classified as low-, moderate- or high-anxiety subjects. A measure of defensiveness was used to assess self-deceptive tendencies. RESULTS: Low-anxiety subjects displayed a higher degree of salt sensitivity compared to moderate- and high-anxiety subjects (P < 0.001), increased heart rate (HR) and electrodermal responses to the stressor compared to moderate-anxiety subjects (P < 0.01 and P < 0.05 respectively) and elevated levels of self-deception compared to moderate- and high-anxiety subjects (P < 0.001). CONCLUSION: Low-anxiety subjects were characterized by a higher degree of salt sensitivity and increased autonomic responsiveness. Defensiveness was also shown to be elevated in this group and might be the underlying psychological trait explaining these findings. Future research on the associations of anxiety and cardiovascular risk should implement measurement of defensiveness in order to identify these subjects at potential risk for cardiovascular disease despite self-reports of low anxiety.