MILD MENTAL STRESS INCREASES INSULIN SENSITIVITY IN HEALTHY-YOUNG MEN

We examined if mental stress alters insulin sensitivity and renal sodi um handling in 11 normotensive young men. Following a 60-minute period of equilibration, we performed euglycemic hyperinsulinemic glucose cl amp for 150 minutes. The clamp period was divided into three phases; c ontrol phase for 90 minutes (I), mental arithmetic phase for 30 minute s (II), and recovery phase for 30 minutes (III). Blood pressure, heart rate and glucose disposal rate (M value) significantly elevated durin g phase II of the stress study. In a time control study, in which ment al arithmetic was not loaded during phase II, blood pressure was kept constant and the changes in M value from phase I to phase II were sign ificantly smaller than those in the stress study. In both studies, fra ctional excretion of sodium did not significantly change throughout th e study period. Thus, insulin sensitivity concerning glucose metabolis m increased in response to mild mental stress. However, the effect of insulin on sodium handling was not altered by the stress.