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Sympathetic-adrenergic activity and acid-base regulation under acute physical stress in type I (insulin-dependent)
S A Yasar1, T Tulassay, L Madácsy
1First Department of Paediatrics, Semmelweis Medical University, Budapest, Hungary.
Insights
Children with insulin-dependent diabetes mellitus (IDDM) experience more severe lactic acidosis and higher norepinephrine levels during physical stress compared to healthy children. This response worsens with longer diabetes duration.
Area of Science:
- Pediatric Endocrinology
- Exercise Physiology
- Metabolic Stress Response
Background:
- Insulin-dependent diabetes mellitus (IDDM) affects children's metabolic regulation.
- The acute physical stress response in pediatric IDDM is not fully understood.
Purpose of the Study:
- To evaluate the physical stress response in children with IDDM.
- To compare catecholamine, lactate, and acid-base status between IDDM children and healthy controls.
Main Methods:
- Measured plasma catecholamines, lactate, electrolytes, fructosamine, glucose, and acid-base status.
- Inducted physical stress using a bicycle ergometer (1.5-1.7 W/kg/10 min) targeting a pulse rate of 170/min.
- Compared four groups: healthy controls, and IDDM children with 2-4 weeks, 5-7 years, and 10-13 years of disease duration.
Main Results:
- IDDM children exhibited pronounced lactic acidosis under stress (lower pH) compared to controls.
- Baseline plasma norepinephrine and epinephrine decreased with longer IDDM duration.
- Stress significantly elevated norepinephrine levels more in IDDM children than controls, negatively correlating with pH.
- Exercise induced blood glucose elevation in most IDDM patients.
Conclusions:
- IDDM children show an exaggerated lactic acidosis and norepinephrine response to physical stress.
- The duration of IDDM may influence the catecholamine response to stress.
- These findings highlight altered physiological responses to acute stress in pediatric IDDM.
Abstract:
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)