Hypoglycemia Prevention When Taking Insulin

group of friends working out

For those taking insulin or insulin secretagogues, care should be taken to avoid hypoglycemia.


Checking your blood glucose before, during and after exercise will provide a framework on which to base your regular routine of insulin, food, and exercise regimen. 

If pre-exercise blood glucose levels are < 100mg/dL (5.6 mmol/L), some carbohydrate may need to be eaten.  About 15 grams of carbohydrate is usually enough to reduce the risk of hypoglycemia.

15 grams of carbohydrate is:

  • A 2 inch in diameter apple
  • 4 ounces of banana (about ½ a medium banana)
  • About 17 medium grapes
  • 1 cup of milk
  • ½ cup of most juices
  • 1 slice of bread
  • 3 to 5 crackers

If pre-exercise blood glucose is high (>250 mg/dL), you should check your urine for ketones. If there are no ketones, you are probably fine to exercise. If there are ketones, you should not exercise.