A 17-year-old boy comes to the office before participating in long-distance running. The patient has a 2-year history of type 1 diabetes mellitus and takes insulin glargine at bedtime and insulin lispro before meals. His home blood glucose levels range from 90 to 130 mg/dL, and he has had no episodes of hypoglycemia. The patient wants to run a marathon and has begun training recently. Physical examination is normal. Hemoglobin A1c is 6.5%. Which of the following is the most appropriate recommendation to manage his diabetes mellitus during long-distance training?

Question

A 17-year-old boy comes to the office before participating in long-distance running.  The patient has a 2-year history of type 1 diabetes mellitus and takes insulin glargine at bedtime and insulin lispro before meals.  His home blood glucose levels range from 90 to 130 mg/dL, and he has had no episodes of hypoglycemia.  The patient wants to run a marathon and has begun training recently.  Physical examination is normal.  Hemoglobin A1c is 6.5%.  Which of the following is the most appropriate recommendation to manage his diabetes mellitus during long-distance training?

Quizplus · Accepted Answer

11ec25c8_d5f5_1bb1_bc81_67acae3b547f_MD0003_00 Repeated muscle contraction during exercise induces increased uptake of glucose by skeletal muscle cells. In normal individuals, overt hypoglycemia does not occur because a drop in the blood glucose level suppresses insulin release from pancreatic beta cells, and counterregulatory hormones (eg, glucagon) increase endogenous glucose production (ie, glycogenolysis, gluconeogenesis). However, patients taking exogenous insulin are vulnerable to exercise-induced hypoglycemia because insulin will continue to be released from the injection site. In addition, exercise may cause changes in skin perfusion that can lead to erratic insulin absorption. Because of the increased insulin sensitivity associated with exercise, a reduction in insulin dose is usually appropriate. For training sessions within 3 hours of a meal, the premeal bolus insulin dose preceding exercise should be reduced. For prolonged exercise (eg, distance running) the basal insulin will likely need reduction as well. Patients with diabetes who initiate a strenuous exercise regimen should also be counseled to increase carbohydrate intake, particularly if training sessions are >60 minutes in duration. (Choice A) Some experts advise a mixed snack containing carbohydrate and protein during the recovery phase following exercise. However, protein intake prior to exercise will not prevent hypoglycemia and is not necessary. (Choice B) Completion of a marathon requires hours of continuous exertion. Limiting training sessions to 30 minutes will not allow proper conditioning and may increase the risk of injury during the event. In addition, a gradual increase in training sessions beyond 30 minutes will allow the patient to learn how to adjust insulin doses appropriately. (Choice D) Eliminating basal insulin (eg, glargine) in patients with type 1 diabetes can lead to severe hyperglycemia and increase the risk of ketoacidosis. (Choice E) Testing for ketosis is not routinely needed for patients with type 1 diabetes but can be considered for those who are participating in strenuous exercise and have significant hyperglycemia (eg, glucose >250 mg/dL). If feasible, home blood testing for beta-hydroxybutyrate is preferred to urine ketone testing. Educational objective: Exercise increases glucose uptake by skeletal muscle cells. Patients with type 1 diabetes taking a basal-bolus insulin regimen should decrease premeal bolus insulin prior to exercise; for prolonged exercise, basal insulin should be decreased as well. Patients with diabetes who initiate a strenuous exercise regimen should also be counseled to increase carbohydrate intake, particularly if training sessions are >60 minutes in duration.

A 17-Year-Old Boy Comes to the Office Before Participating in Long-Distance