Discontinuation of insulin pump treatment (CSII) before, during and after physical activity is a common practice among a number of patients. The aim of the study was to evaluate the course of insulinemia during a 3- hour insulin pump suspension and after consecutive insulin bolus administration, and additionally, to assess the effect of physical activity (mid intensity aerobic exercise).We enrolled 12 patients with diabetes mellitus type 1 in the study (men, mean age 33.4 ± 8.66 years, diabetes duration 16.3 ± 8.76 years, CSII treatment duration 6.9 ± 4.60 years, BMI 25.7 ± 3.75 mg/ m2, HbA1c 8.4 ± 0.95%, total insulin dose 50.3 ± 12.50 IU/ day). The tests were performed after night fasting at usual insulin doses, without serving breakfast and morning bolus dose. In the course of the test, insulin administration by a pump was suspended for 3 hours. Blood for assessment of blood glucose and insulinemia was taken in 30- minute intervals during the test. A test with or without physical exercise on bicycle ergometer was performed in each patient 2 weeks later.We did not prove any influence of physical exercise on insulinemia during suspended insulin deli-very by an insulin pump. Insulinemia of approximately 50% of the original value persisted for another 90 minutes following insulin pump suspension. A rapid increase in insulinemia occurred after bolus administration in the 180th minute of the test. However, the decrease in blood glucose level did not occur until after another 90 minutes.When modifying CSII treatment by reduction or suspension of insulin delivery it is essential to bear in mind the gradual decrease in insulinemia as well as the delay in insulin action following bolus administration.
