Don’t Let Blood Sugar Get in The Way of Exercise: Tips for Working Out with Diabetes

Posted by ids on Tue, 07/08/2014 - 15:09 in

 - Gary Scheiner, MS, CDE

Every now and then, it is worth recognizing exercise for the amazing “medicine” that it can be for people with diabetes. What else improves insulin sensitivity, blunts post-meal blood sugar spikes, promotes weight loss, improves cholesterol and blood pressure, enhances mood, dulls pain and helps fight male pattern baldness? OK, I made up that last one. But the rest are proven true.

So why aren’t more people exercising? One of the major reasons given by people with diabetes is fear of hypoglycemia (low blood sugar). As an exercise physiologist and certified diabetes educator, it’s my job to keep that from happening.

Who is at Risk for Low Blood Sugar?

Anyone who uses insulin is at risk of having low blood sugar - particularly those who take mealtime insulin or premixed insulin formulations containing NPH. There are also certain diabetes pills that can cause hypoglycemia - namely those that stimulate the pancreas to secrete extra insulin. These include sulfonylureas (glipizide, glyburide, glimeperide), meglitinides (repaglinide, nateglinide) and “combination” medications that contain any of these. If you don’t take insulin or any of these medications, you should not have to worry about developing hypoglycemia!

Making Insulin Adjustments for Exercise

Most daily activities (including yard work, cleaning and shopping) and aerobic exercises (activities performed at a moderately challenging level over a period of 15 minutes or more) can promote a drop in blood sugar. To prevent hypoglycemia, you can reduce insulin/medication or increase your carbohydrate intake.

When exercise is going to be performed within an hour or two after a meal, the best approach is usually to reduce your mealtime insulin or oral medication. When adjusting mealtime insulin, both aspects (the dose to cover food and the dose to cover a high reading) should be reduced. The amount of the reduction can vary from person to person and situation to situation, but the chart below should give you a good starting point (reduce your usual insulin dose by the percentages noted):

Short Duration
(15-30 minutes)

Moderate Duration
(31-60 minutes)

Long Duration
(1-2 hours)

Low Intensity (relatively easy)




Moderate Intensity




High Intensity (very challenging)




If you take a medication that can cause hypoglycemia, it is usually best to take your usual dose with your first couple of exercise sessions and see what happens. If your blood sugar drops below 80 mg/dL during or after exercise, reducing the medication might be in your best interest. Check with your physician before making this type of change on your own.

If you take long-acting/basal insulin and plan to exercise after a meal, consider having a little more carbohydrate than usual. Likewise, if you plan to exercise before or between meals, the best approach is usually to have some carbohydrate prior to the activity. The size of the snack depends on the duration and intensity of your workout. The harder and longer your muscles are working, the more carbohydrate you will need to eat in order to keep your blood sugar from dropping. The amount is also based on your body size: the bigger you are, the more carbohydrate you will need.

Although there is no way of knowing exactly how much you will need, the chart below should serve as a safe starting point. Note that this represents the grams of carbohydrate needed for one hour of activity. If you exercise for half an hour, cut the amount in half. And it’s best to choose carbohydrates that digest quickly and easily, such as juice, crackers, sports drinks or sweet (non-chocolate) candies.

Carbohydrate Needed Per 60 Minutes of Physical Activity

50 lbs.
(23 kg)

100 lbs.
(45 kg)

150 lbs.
(68 kg)

200 lbs.
(91 kg)

250 lbs.
(114 kg)

Low Intensity

5-8 g

10-16 g

15-25 g

20-32 g

25-40 g

Moderate Intensity

10-13 g

20-26 g

30-40 g

40-52 g

50-65 g

High Intensity

15-18 g

30-36 g

45-55 g

60-72 g

75-90 g

One other thing to watch out for is delayed onset hypoglycemia. This is a low blood sugar that can occur several hours after intense/prolonged (exhaustive) exercise. If you’re concerned about a delayed drop in your blood sugar, you can reduce your basal insulin, consume extra snacks or reduce your usual mealtime insulin doses following hard workouts.

Now get out there and exercise! And don’t let fear of low blood sugar get in your way.

The Omnipod insulin pump allows you to create temporary basal rates for different situations, like during exercise or physical activity. Click here to request a free demo.

Gary Scheiner, MS, CDE
Owner & Clinical Director, Integrated Diabetes Services LLC 

Gary-ScheinerAn award-winning Certified Diabetes Educator, Masters-level Exercise Physiologist and person with type 1 diabetes since 1985, Gary Scheiner has dedicated his professional life to improving the lives of people with insulin-dependent diabetes. He was recently named 2014 Diabetes Educator of the Year by the American Association of Diabetes Educators. Gary serves on the faculty of Children with Diabetes and is an active volunteer for the American Diabetes Association, Juvenile Diabetes Research Foundation, Insulindependence and Setebaid Diabetes Camps. He also serves on the clinical advisory boards for several diabetes device manufacturers and pharmaceutical companies.

NOTE:  Information posted on Podder Talk is not intended to be taken as medical advice. Always consult with your healthcare provider for questions and guidance on managing any health-related issues.