Use of a modified basal rate of insulin to prevent post-exercise hypoglycemia in adolescents with type 1 diabetes on continuous subcutaneous insulin infusion

Document Type



Paediatrics and Child Health


Introduction: An increased number of adolescents with Type 1 Diabetes Mellitus are choosing CSII to maintain normoglycemia. However, the opti- ma1changes to make in the basal rate of insulin to prevent post-exercise hypo- glycemia are not known.
Methodology: To address this question, 8 adolescents (age: 14.6 -£ 0.5 years) were studied in our General Clinical Research Center on 2 occasions following a standard evening meal. At each visit, the patients underwent a similar exercise protocol 2 hours after eating that involved 30 minutes of standardized strenuous activity on an exercise bicycle. On one visit(CONTROL), no changes were made in the basal rate of insulin administration; on the other visit (TEST), the basal rate was halved for 3 1/2 hours around the exercise. The patients’ plasma glucose levels were measured serially for 10 hours following exercise.
Results: Initial mean plasma glucose concentrations were similar on the two study days (TEST — 194 24. mg/d1; CONTROL = 180 15 mg/d1). There was a similar fall in plasma glucose concentrations (expressed as % of basal) in each of the groups. (TEST = -31 A5 % of basal; CONTROL = - 36 10 % of basal). There was no difference in the area under the plasma glucose curve on both visits, nor was there any difference in the slopes of the plasma glucose curves during and immediately after exercise. Two of the patients in the CONTROL group developed asymptomatic hypoglycemia (plasma glucose < 70 mg/dl) within 6 hours of the exercise, but this occurrence was not statistically different.
Conclusion: In our study, halving the basal rate of insulin did not make a significant difference on average plasma glucose values after exercise. Further studies with larger subject numbers need to be performed to determine the optimal changes to make in CSII to prevent post-exercise hypoglycemia.


This work was published before the author joined Aga Khan University.