Long-acting insulin unaffected by exercise

In people with insulin-dependent type 1 diabetes, exercise does not appear to increase the rate of absorption of insulin glargine (Lantus), a long-acting insulin analog, according to study findings.

"This study suggests that insulin glargine can be safely and effectively administered without a dose change during exercise," Dr. David R. Owens, of Llandough Hospital, South Glamorgan, Wales, and colleagues report in the journal Diabetes Care.

However, they note that the study does not rule out the possibility of late exercise-induced low blood sugar, also called hypoglycemia, and "insulin glargine reduction may be warranted depending on individual patient responses."

The investigators compared the effect of exercise on the absorption of injected insulin glargine in 13 patients with type 1 diabetes. The usual insulin dose was given in the thigh on the evening before the exercise study on two occasions 1 week apart.

The patients were randomized to 30 minutes of intense exercise, 1 hour after a meal. They compared the decay of radiolabeled insulin glargine on the two occasions and they collected blood samples to assess blood sugar and insulin profiles.

As expected, the investigators observed a significant fall in blood sugar on the exercise day during the exercise period. However, no significant difference was observed in the rate of insulin glargine decay on the 2 study days (exercise versus no exercise).

The team cautions against over interpreting these results, noting that real-world exercise activity may have different effects on glargine absorption.

SOURCE: Diabetes Care March 2005.