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Diabetes: Why some workouts raise blood sugar

Nov. 3, 2023— If you have diabetes, exercise can help lower blood sugar and regulate it over time. But you should know that certain activities can actually raise your blood sugar in the short term.

What's behind the rise?

During physical activity, your muscles burn glucose. In most cases, that lowers blood sugar, according to the American Diabetes Association. But some workouts cause your body to produce adrenaline and other stress hormones, which tell your liver to release more glucose.

Timing matters too. Your blood sugar changes throughout the day, and it may be higher in the early morning—between 4 a.m. and 8 a.m. If that's when you exercise, the result may be higher blood sugar.

Your pre-workout snack can also be a factor. If your exercise doesn't counter the carbs you eat before you begin, the end result can be a rise in blood sugar.

Choose the right workout

Any activity is possible for people with diabetes, and the best exercise is one you’ll want to keep doing. But it’s important to know how your activity affects your blood sugar. According to the JDRF, for people with type 1 diabetes:

  • Long, moderate-intensity exercises, like swimming or running, tend to cause a drop in blood sugar.
  • Short, high-intensity anaerobic activities, like sprinting, ice hockey or weight training, can trigger a spike in blood sugar.

Whatever type of exercise you choose, check your blood sugar before, during and after your workouts. Doing so will help you track how exercise affects your levels in the short term and allow you to adjust your routine to get the most benefits over time.

Get moving

Physical activity is an important part of staying healthy, especially if you have diabetes. That's because, in addition to lowering your risk of heart disease and helping you maintain a healthy weight, exercise can help you keep your blood sugar in check. According to the Centers for Disease Control and Prevention, most adults should aim for at least 150 minutes of moderate-intensity exercise and one or two sessions of strength training per week.

Ready to get started? If you're new to exercise, talk with your doctor about activities that will work best for you. And start with small goals, like a 10-minute walk after dinner. You can gradually build up to more minutes. You can find more information about diabetes and exercise in our Diabetes health topic center.


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