Acute mental stress-induced alpha or beta-adrenergic reactivity patterns linked to unique cardiometabolic risk...

Cardiometabolic risk may differ based on a stress-induced alpha(α)-adrenergic response versus a predominant beta(β)-adrenergic response. Whether these responses might serve as significant markers of distinct cardiometabolic risk profiles based on hemodynamic reactivity remain unknown. We (1) characterized predominant α-and β-adrenergic hemodynamic response patterns to acute mental stress; and (2) determined the cardiometabolic risk profile within predominant α-or β-adrenergic responders, irrespective of age, sex, or ethnicity. We included 117 South African teachers (aged 20-65 years) and administered an acute mental stress task (Color-Word-Conflict test) for one-minute. Participants' hemodynamic response profiles were characterized as predominant α-adrenergic (decreases in cardiac output (CO) and Windkessel arterial compliance (C_wk) (lowest quartile)) (n = 48) and β-adrenergic (increases in CO, C_wk (highest quartile)) responses (n = 69) via Finometer beat-to-beat hemodynamic monitoring. Ambulatory-BP was measured and the number of 24 H-ischemic events determined by ECG. Cardiometabolic markers were analyzed using fasting blood samples, and abnormal glucose tolerance (Abnl-GT), combining prediabetes and diabetes, was defined as glycated hemoglobin (HbA1c) ≥ 5.7% and/or fasting glucose > 100 mg/dL and/or diabetes medication usage. Predominant α-adrenergic responders presented with an overall poorer cardiometabolic profile, with higher levels of HbA1c, insulin, greater insulin resistance and higher total cholesterol and lower HDL-cholesterol. Adjusted analyses indicated that a predominant α-adrenergic profile had higher odds of central obesity (P = 0.031), low HDL-cholesterol (P = 0.042), 24-H-hypertension (P < 0.001), cardiac stress (P = 0.025), ischemic events (P = 0.048) and medium-to-high 10-year stroke probability (P < 0.001), compared to β-adrenergic responders. In the β-adrenergic responders, higher odds for ischemic events, stroke probability and Abnl-GT were found (all P ≤ 0.022), compared to α-adrenergic responders. Independent of age, sex or ethnicity, the risk profile identified in predominant α-adrenergic responders mainly involved the effects of a high-pressure system, cardiac stress, and ischemia. Whereas in predominant β-adrenergic responders, the risk profile pointed to a more metabolic and hyperperfusion injury-related cardiometabolic risk.