Impact of acute psychological stress on cardiovascular risk factors in face of insulin resistance.

Individuals with insulin resistance (IR) are at greater risk for cardiovascular disease (CVD). Psychological stress may contribute to develop CVD in IR, although mechanisms are poorly understood. Our aim was to test the hypothesis that individuals with IR have enhanced emotional and physiological responses to acute psychological stress, leading to increased CVD risk. Sixty participants were enrolled into the study, and classified into IR group (n = 31) and insulin sensitive group (n = 29) according to the Quantitative insulin sensitivity check index, which was calculated based on an oral glucose tolerance test. The Trier social stress test, a standardized experimental stress paradigm, was performed on each participant, and emotional and physiological responses were examined. Blood was collected from each subject for insulin, cytokines, and cortisol measurements. Compared with the insulin-sensitive group, individuals with IR had significantly lower ratings of energy and calm, but higher fatigue levels in response to acute stressors. Individuals with IR also showed blunted heart rate reactivity following stress. In addition, the IR status was worsened by acute psychological stress as demonstrated by further increased insulin secretion. Furthermore, individuals with IR showed significantly increased levels of leptin and interleukin-6, but decreased levels of adiponectin, at baseline, stress test, and post-stress period. Our findings in individuals with IR under acute stress would allow a better understanding of the risks for developing CVD and to tailor the interventions for better outcomes.