05/11/2010 - Questions and Answers

My blood sugar numbers go really high when I exercise, why?

By: June Chen, MD



I have diabetes, my blood sugar numbers go really high when I exercise, why?


Exercise may cause low blood sugar or high blood sugar due to an increase in metabolic demands and due to the activity of insulin. Here are some ways to help prevent low or high blood sugars in diabetics who exercise:

  • Avoid injecting insulin into parts of the body which will be exerted during exercise, as exercise may prolong or shorten the time of insulin reaction.
  • Avoid exercising at the peak of insulin activity. Insulin should be administered approximately one hour before you begin exercising.
  • Avoid alcohol and beta blocker drugs around the time of exercise because they may cause low blood sugar.
  • Eat a snack just before and during exercise, and monitor your blood sugars before, during, and after exercise.
  • Keep simple carbohydrates, such as fruit juice or hard candy, and other food available. Also keep some extra insulin with you in case of emergencies.
  • If you experience pain in your chest, nausea, heart palpitations or severe shortness of breath during exercise, stop and consult your doctor.


Created on: 05/11/2010
Reviewed on: 05/11/2010

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