Postexercise late-onset hypoglycemia in insulin-dependent diabetic patients.

A new clinical entity that is prevalent in young type I (insulin-dependent) diabetic patients, postexercise late-onset (PEL) hypoglycemia, is described. A prospective case-finding study suggested that PEL hypoglycemia occurred in 48 of approximately 300 diabetic type I patients who were diagnosed as diabetic before age 20 yr and who were monitored for up to 2 yr. Typically, hypoglycemia was nocturnal and occurred 6-15 h after the completion of unusually strenuous exercise or play. In more than half the cases the hypoglycemia resulted in loss of consciousness or seizures and necessitated treatment with subcutaneous glucagon or intravenous glucose and/or attendance by a health professional. The hypoglycemia was not limited to patients in good or excellent metabolic control and often occurred after a single bout of exercise in patients unaccustomed to exercise or in athletic patients who were making the transition from an untrained to a trained state. Surprisingly, 12 of the patients who experienced nocturnal PEL hypoglycemia were not using significant amounts of insulin that peaked at night. Type I diabetic patients should be made aware of the possibility of PEL hypoglycemia to enable them to make adjustments in their management plans in anticipation of unusually strenuous exercise, so that they may attempt to minimize or avoid late-onset hypoglycemia.