When It's Okay to Exercise with Diabetes

There are times that you need to be extra careful if you plan to exercise.  Below are some reminders.

When your insulin is working the hardest. If you take insulin, you know it lowers your blood glucose. Exercise also lowers blood glucose. When exercise and insulin are working together, your blood glucose may drop too low. Learn to adjust your insulin or eat extra food at these times.

When blood glucose is high. If your diabetes has been poorly controlled for a period of time because of lack of insulin, exercise will not lower your blood glucose. Fortunately, this doesn’t happen very often these days. Times to be concerned about might be at diagnosis when you didn’t realize you had diabetes and your blood glucose levels had been elevated for several days, or with illness, such as the flu. It is usually recommended that you not exercise with high blood glucose, especially with ketones, and if you are not feeling well. Call you healthcare providers instead, and work to lower your blood glucose to the proper level.

 When exercising during the evening. You are at greater risk of low blood glucose levels overnight if you exercise late in the evening. It is important to have a bedtime snack if you exercise after your evening meal or to know how to use insulin adjustments for these times. If possible, it’s helpful if exercise can be completed two hours before bedtime.

Avoid alcohol before or immediately after exercise. Alcohol without food intake can lead to hypoglycemia and adding exercise increases the risk of low blood glucose.

 Avoid hot tubs, saunas and steam tables directly after exercise. Hot tubs, saunas and steam tables continue to maintain an increased heart rate and may lower your blood glucose. 

Below are guidelines for exercising: 

Type 1	If fasting blood glucose is 250 mg/dl or higher, check for ketones;if positive for ketones, DO NOT exercise.  If blood glucose is between 251 and 300 mg/dl, and negative for ketones, it is okay to exercise. If blood glucose is over 300 mg/dl, and negative for ketones, exercise with extreme caution. Check blood glucose levels 10 to 15 minutes into exercise to make sure it is dropping. Make sure you drink plenty of water to stay hydrated.
Children with type 1	Follow the guidelines above -- except that it is okay to exercise with blood glucose levels up to 400 mg/dl.
Type 2	Can exercise with blood glucose levels of up to 400 mg/dl (regardless of whether or not using insulin)

Find more information about physical activity and diabetes in Staying Healthy with Diabetes – Physical Activity & Fitness available from the Joslin Online Store.