Exercise and Managing Your Blood Sugar

Experiencing low blood sugar during or after exercise is not just annoying, it is potentially dangerous. To manage low blood sugar associated with physical activity, check your blood sugar before, during (if necessary) and after you exercise and always be prepared to correct it.

Regular exercise is important to overall health and wellness, making it well worthwhile. However, exercise presents challenges for people with diabetes because any increase in activity may lead to developing hypoglycemia.

The more you understand about what affects your blood sugar levels during exercise, the easier it may become to manage, leading to more confidence in being physically active and staying in control of your diabetes.

If you or your child participates in sports, others (including the team coach and maybe even team mates) should be aware of diabetes and hypoglycemia basics and being prepared to assist you with correcting low blood sugar.

Prevent Lows Before, During and After Exercise

You can manage blood sugar while making exercise a regular part of your life.

Here are some tips:

  • Learn how your body responds to different types of exercise by checking your blood sugar levels before, during and after a session.
  • If your blood sugar is below 100 mg/dL before you start exercising, take steps to raise it before you begin.
  • Always be prepared to correct low blood sugar by having a glucose product with you during exercise. Do not assume that you will be able to find glucose or other food sources of carbohydrate nearby if you need it when you are exercising.
  • If you exercise for a long time and/or with high intensity, you will likely need to consume carbohydrate before and during the activity to help prevent fatigue and hypoglycemia.
  • Whenever exercising for an extended period of time, check your blood sugar at regular intervals to catch lows early.
  • Consult with your healthcare professional about any changes in frequency and/or intensity of exercise to determine what changes to diet and/or medication may be necessary.

How to Correct Exercise Related Low Blood Sugar

Once you begin to notice symptoms of hypoglycemia:

Step 1. Stop exercising immediately and eat 15-20 grams of pure glucose or another food containing fast-acting carbohydrate.

Pure glucose is the preferred carbohydrate to correct low blood sugar. If you do not have a pure glucose product, such as Dex4 tablets, liquids or gels, consume another fast-acting carbohydrate such as fruit juice, regular soda, low or non-fat milk or hard candies.

Step 2. Wait 15 minutes and check your blood sugar again.

If your blood sugar is still below your target range, repeat step 1. Do not resume exercise until your blood sugar is above 100 mg/dL or in your target range.

Intense Workouts May Raise Your Blood Sugar

After a session of intense exercise, there is a chance you may experience high blood sugar (hyperglycemia). This is due to an increase in stress hormone (glucose-raising hormone) levels. In one study, a group of people with type 1 diabetes using insulin pumps experienced elevated blood glucose levels for up to two hours after cycling to near-exhaustion.

Like hypoglycemia (low blood sugar), hyperglycemia is a dangerous condition. It is important to consult with your healthcare professional before beginning an intense exercise regimen or if you are planning any change in physical activity.


American Diabetes Association. Foundations of care: education, nutrition, physical activity, smoking cessation, psychosocial care, and immunization. Sec. 4. In Standards of Medical Care in Diabetes—2015. Diabetes Care 2015;38(Suppl. 1):S20–S30.

Chiang JL, Kirkman MS, Laffel LMB, Peters AL, on behalf of the Type 1 Diabetes Sourcebook authors. Type 1 diabetes through the life span: a position statement of the American Diabetes Association. Diabetes Care 2014;37:2034–2054. DOI: 10.2337/dc14-1140

Optimize Your Diabetes Regimen for Physical Activity
  • Check your blood sugar level before, during (if necessary) and after physical activity. Consult your healthcare professional if you have repeated problems with managing your blood glucose during and/or after exercise.
  • Avoid physical activity, or correct it before beginning physical activity, if your blood sugar is outside of your target range. It is commonly recommended, if blood sugar is trending low before physical activity, to eat a pre-exercise snack.
  • Always keep fast-acting carbohydrate on hand. Dex4 glucose tablets, liquids and gels work well because they are pure glucose, do not require refrigeration, are easy to carry, and packaged for quick and easy access.
  • Take precautions when doing physical activity in extremely hot or cold environments, as these conditions can have an added effect on blood sugar levels.
  • Wear a medical ID to let others know that you have diabetes in case of an emergency.
  • Keep in mind that children may be more prone to variability in blood sugar levels when it comes to physical activity. Consult with your healthcare professional and give extra attention to your child’s needs during physical activity. Make sure that teachers and athletic coaches are made aware of your child’s condition and know how to assist when hypoglycemia occurs.