Background: The aim of this study was to evaluate the influence of physical activity on blood glucose, insulinemia, and ketone bodies level during interruption of insulin delivery.
Methods: We enrolled 12 patients with type 1 diabetes (men with an average age of 33.4±8.66 years, body mass index of 25.7±3.75 mg/m(2), and glycated hemoglobin of 8.4±0.95%). The test was performed after overnight fasting at the usual insulin dosage. The delivery of insulin by the pump was stopped for 3 h, and blood samples were obtained in 30-min intervals for determination of blood glucose, insulinemia, β-hydroxybutyrate, non-esterified fatty acids, and acid-base balance parameters. A test with (EXE) or without (CON) physical exercise (moderate aerobic exercise) was performed in each patient at random in the course of 2 weeks. Results are presented as median (first quartile; third quartile).
Results: Groups CON and EXE did not differ in blood levels of insulin during the test. Regarding time course of glycemia, we found differences only in min 270 for CON versus EXE of 15.2 (13.6; 16.7) and 13.9 (9.1;16.5) mmol/L, respectively (P=0.038). Concerning blood levels of β-hydroxybutyrate, we found significant differences in min 180-300 of the test: CON of 419 (354; 541), 485 (344; 580), and 107 (63; 156) μmol/L versus EXE of 690 (631; 723), 703 (562; 871), and 241 (113; 507) μmol/L (P<0.01). Comparable results were found in values of total ketone bodies and free fatty acids.
Conclusions: The influence of physical activity during a 3-h interruption of insulin pump treatment is evident, especially in the increase in plasma levels of non-esterified fatty acids and ketone bodies. Correction bolus leads to a rapid increase in insulinemia; however, normalization of blood glucose and ketone bodies is achieved within another 90 min.