Adrenaline during mental stress in relation to fitness, metabolic risk factors and cardiovascular responses in young men.

We studied plasma adrenaline (A) in relation to physical fitness, metabolic cardiovascular risk factors and cardiovascular responses. Men (age 21-24 years) with high and normal (both n=19) screening blood pressure (BP) were studied cross-sectionally. We measured peak oxygen uptake (VO2peak) (treadmill exercise), and plasma catecholamines, heart rate (HR), finger systolic (SBP) and diastolic (DBP) BP, and insulin-adjusted glucose disposal rate (GDR/I) during a hyperinsulinaemic glucose clamp (rest) and mental arithmetic stress test (MST). By multiple regression, A at rest (Arest) (beta=0.37, p<0.05) and during MST (Amst) (beta=0.40, p<0.01) were associated with high screening BP. In the respective models, Arest was negatively related to body mass index (BMI) (beta=-0.56, p<0.001) and Amst positively to VO2peak (beta=0.54, p<0.001). BP and HR responses correlated positively with VO2peak, but were determined by Amst in multiple regression models. Independently of BMI and VO2peak, serum high-density lipoprotein cholesterol was positively related to A levels, whereas GDR/I was independently related only to VO2peak. Increased adrenaline secretion may be related to high BP, but may at the same time be associated with a beneficial metabolic profile.