The Highs and Lows of Exercise and Diabetes

Exercise confers many benefits in adolescents, but it also increases the risk for hypoglycemia in those with type 1 diabetes. Investigators in Australia examined this phenomenon in nine adolescents (4 females; mean age, 16) with diabetes (mean duration, 8 years; mean HbA_1c, 7.8%).

The adolescents underwent testing for 2 days on two occasions (4 weeks apart): on one day during and after 45 minutes of exercise on a cycle ergometer and on the other day while at rest (control). On each test day, participants ate their usual breakfast at home and took their normal insulin dose, ate lunch at noon in the lab (comparable to what they would normally eat), and either rested or exercised at 4:00 PM. Intravenous insulin and glucose were administered to …