To evaluate the efficacy of the acute-physical-stress response, plasma catecholamine and lactate levels, serum electrolytes, fructosamine, blood glucose and acid-base status were measured in insulin-dependent diabetes mellitus (IDDM) children and the data compared to those of healthy controls. Four groups were studied: group 1, healthy controls; group 2, newly diagnosed diabetic patients with an IDDM duration of 2-4 weeks; group 3, with an IDDM duration of 5-7 years; group 4, with an IDDM duration of 10-13 years. According to their fructosamine levels, IDDM children were in a well-controlled metabolic state. The physical stress was induced by 1.5-1.7 W/kg/10 min bicycle ergometer determined by a target pulse rate of 170/min. IDDM children exhibited pronounced lactic acidosis under stress (pH: group 2, 7.27 +/- 0.07; group 3, 7.28 +/- 0.05; group 4, 7.20 +/- 0.04, vs. group 1; 7.34 +/- 0.03). Baseline plasma norepinephrine and epinephrine levels showed a significant decrease parallel to the duration of IDDM. Stress induced an increase in the concentration of norepinephrine in each group, but the elevation was significantly higher in the IDDM children versus the controls. A significant negative correlation was found between pH and maximal plasma norepinephrine levels (y = 7.3-0.006x, r = -0.46, p < 0.02). Stress resulted in blood glucose elevation in 13 patients regardless of their pre-exercise blood glucose levels.(ABSTRACT TRUNCATED AT 250 WORDS)