Stopping insulin avoids drop in sugar

In children with type 1 diabetes who were treated with insulin pump therapy, temporarily stopping insulin helped prevent a decline in blood sugar (hypoglycaemia) during exercise. However, as might be expected, the risk of high blood sugar (hyperglycaemia) increased. Regular exercise is encouraged for children with type 1 diabetes, but it is often difficult to maintain normal sugar levels during prolonged periods of physical activity. In particular, exercise can lead to an increased use of sugar, resulting in hypoglycaemia. A number of previous studies have looked at the process of exercise-induced hypoglycaemia in children with type 1 diabetes, but few have examined strategies for preventing this problem. Researchers from the Jaeb Center for Health Research in Tampa, Florida, USA, evaluated the effect of stopping the insulin pump during exercise in 49 diabetic children. The subjects were randomly assigned to stop or not stop insulin during four 15-minute treadmill cycles (target heart rate of 140 beats per minute), interspersed with 5-minute rest breaks. Sugar levels were measured before, during, and after exercise. The children switched groups and the process was repeated on a second day. The rate of hypoglycaemia (defined as a blood sugar level of 70 milligrams per deciliter or lower) was 16 percent when insulin was stopped compared with a rate of 43 percent when insulin was not stopped. The rate of hyperglycaemia, defined as an increase in sugar levels of at least 20 percent, to at least 200 milligrams per deciliter at 45 minutes after completion of exercise, was higher in the group with insulin stopped: 27 percent vs. 4 percent. The above results show that turning off the insulin pump during exercise is an effective strategy for reducing hypoglycaemia in children with type 1 diabetes, but the risk of hyperglycaemia is increased. Though this strategy is possible for patients on insulin pump therapy, it is not feasible for those who take multiple daily injections of long-acting insulin for insulin replacement.