Living with diabetes blog

Diabetes: Balancing your insulin, medication and exercise

By Nancy Klobassa Davidson, R.N. and Peggy Moreland, R.N., C.D.E. September 13, 2013

Controlling diabetes is a balancing act. You must carefully balance food, activity (exercise), and medications and insulin. All three are equally important to your health, and each can increase or decrease your blood glucose levels. Many of our readers ask if they need to adjust their insulin or medication before exercise.

Physical activity, or exercise, includes anything that gets you moving, such as walking, dancing or working in your garden. Staying active improves your overall health. Regular exercise helps you:

  • Better control glucose levels
  • Increase overall fitness
  • Feel more energetic
  • Improve flexibility
  • Improve blood pressure
  • Lower your risk of developing cardiovascular disease
  • Improve your appearance, weight and overall sense of well-being

Insulin and diabetes medications lower your blood glucose. The amount of medication you need is unique to you. The time of day you take your medication and how much you take are important factors in allowing your medication to work when your blood glucose rises.

As you make exercise a part of your life, your diabetes health care provider may change or adjust your medications based on the results recorded in your diabetes record book. It's a balancing act — if you eat more than your meal plan allows, your blood glucose level may rise, or, if you exercise less than usual, your blood glucose level may rise.

Several factors affect your blood glucose during activity or exercise:

  • Your physical condition
  • Length of activity or exercise
  • Type of activity or exercise
  • Blood glucose level prior to exercising

When you're more active than usual, your blood glucose may drop too low, causing low blood glucose (hypoglycemia). It's important that you prepare ahead of time. If you're taking insulin and you know ahead of time when you will exercise, decrease your rapid or short insulin meal dose before the activity instead of taking extra food during the activity. Talk with your diabetes health care team for help making the decision about how much to decrease your insulin dose.

Also, avoid injecting insulin into your arms and legs that you will use during your activity or exercise. An abdominal injection site may help lower the risk for hypoglycemia associated with exercise.

Some additional tips:

  • Test your blood glucose before, during and after the activity to monitor how it affects your blood glucose level. This is important when beginning or changing your exercise program.
  • When your insulin is peaking, exercise isn't recommended, as it may lead to low blood glucose. Before you exercise, take less insulin or eat more food at mealtime or as a snack.
  • If your blood glucose is less than 70 mg/dL (3.8 mmol/L), take 1 to 2 carbohydrate choices and make sure your blood glucose is in goal range before you begin the activity or exercise.
  • If you were in goal range before the activity and the activity drops your blood glucose more than 30 to 50 mg/dL (1.6 to 2.7 mmol/L) or hypoglycemia occurs — blood glucose less than 70 mg/dL (3.8 mmol/L) — stop exercising and take 1 carbohydrate choice. Recheck your blood glucose after 15 minutes and repeat until your blood sugar returns to a safe range. Then, return to your exercise and take 1 carbohydrate every 30 to 60 minutes while you're active.
  • Don't exercise if your blood glucose is greater than 300 mg/dL (16 mmol/L). Exercising with blood glucoses over 300 mg/dL (16 mmol/L) can raise your blood glucose even more, because exercise causes the body to release or produce extra glucose and there won't be enough insulin available to use it.
  • With harder or more strenuous activity, even if you're within goal range or above goal, 2 carbohydrate choices may be necessary to prevent low blood glucose. Ask your health care provider if you have questions about this.
  • For longer duration or very strenuous activities, such as downhill/cross country skiing or long bike rides, take 1 carbohydrate choice every 30 to 60 minutes during the activity. Check your blood glucose every 1 to 2 hours during the activity.
  • It isn't recommended that you be active or exercise when you're sick.
  • We generally don't recommend exercising before bed due to the risk of delayed post-exercise hypoglycemia. If evening exercise is necessary, consider eating an extra carbohydrate after exercise to reduce the risk of hypoglycemia while sleeping.

Remember, it's essential to check with your health care provider if you've been sedentary and want to begin an exercise routine.

Have a great week!


Sept. 13, 2013