updated 12/2019 

The assumption generally made is that exercise will serve to decrease blood glucose levels.


Brittle diabetics need to be aware that sugar levels can go in either direction, up or down, during and following a workout.  This complicates matters for a brittle person who never really knows which direction their blood glucose is heading . This requires careful and continuous monitoring on their part to ensure a margin of safety while working out.

As a result, a series of general guidelines have been recommended for Type 1 diabetics by health care professionals :

You should always discuss with your doctor and members of your health care team a plan for developing an exercise program suited to your condition. Since each person’s diabetic response is individualized, an exercise program should be customized to prevent worsening any problems you may already have. Ask your doctor to recommend the best type, time and level of exercise you should engage in.  By trial and error you will eventually adjust to a regimen that is specific to your body’s response pattern.


  • Exercise 1 to 1.5 hours after eating.

  • Drink water to hydrate the body – recommendation: 16 oz. 2 hours before, 8 oz. ½ hour before and 4 to 6 oz. every 15 minutes while exercising.

  • Monitor BG before, during and after exercising.

  • If your BG level is between 100 and 250mg/dL prior to exercising, it is generally considered safe to begin your workout routine.

  • If below 100mg/dL, the recommendation is to eat a carbohydrate rich snack (15 to 30 gr) prior to beginning the exercise program.

  • If between 250 and 300mg/dL , be sure to test for ketones in your urine.

    If positive , don’t exercise otherwise you risk DKA. Postpone until ketones decline to normal levels.

  • If negative , begin exercising but be sure to test 10 minutes after the start to determine BG levels. If rising stop exercising. If declining, continue.


Many diabetologists set as a rule of thumb – Do not exercise if your BG levels are 300mg/dL or higher.

Other safety precautions;

  1. If your experiencing an illness, don’t exercise until symptoms disappear. Illness affects BG levels.

  2. You should exercise in a public place, workout with a partner whose aware of your condition and who knows what to do in the case of an emergency, wear a medic alert bracelet, carry a cell phone, and carry supplies, water for hydration, glucose tablets , fruit drink or regular soda and glucagon for hypoglycemic episodes,  and insulin in the event of  hyperglycemia.

  3. Remember that exercise is a form of stress which triggers the release of stress hormones causing the liver to release glucose into the bloodstream. In the absence of insulin, glucose levels rise.