Sorry, you need to enable JavaScript to visit this website.
hamburger overlay

Different activities: Different effects. Preparing to exercise depends on what you plan to do.

Christel, co-founder of Diabetes Strong talked to us about her experience managing blood sugar while exercising, and how different types of activity impact her blood sugar levels. These are some of the ideas she's been sharing with her coaching clients and on her blog, and are now becoming more widespread among doctors.

Before and during exercise

In the past, recommendations for managing your numbers while exercising didn't differentiate between different types of physical activity.1 However, recent research has shown that different types of activity can have distinct effects on your blood sugar.2,3

  • Aerobic or cardio exercise, such as walking, cycling or swimming, tends to lower blood sugar. You may need to have a snack, cut back on insulin or both before you begin. If necessary, opt for a snack that's high in fiber or protein so it doesn't spike your blood sugar levels. Of course, you may need additional carbohydrates if you're endurance training, but right now, we're just talking about keeping your blood sugar in line during regular workouts.
  • Strength training, such as lifting weights, can increase blood sugar or provide greater stability in your numbers. Eating a snack beforehand may actually send your numbers too high.
  • Interval training, in which you switch between brief periods of intense cardio and moderate recovery exercises, may lead to less variation in blood glucose numbers. As a result, reducing insulin too much could lead to high blood sugar.

These are generalizations—there are many variables, including the order in which you go from one type of exercise to the next, how fit you are, your starting glucose level, the duration and intensity of exercise, and more. The answer? Monitor your blood sugar closely before, during and after exercise.2 By tracking your numbers, snacks, insulin and your body's response to activity, you'll learn know how different exercises affect you. That way, you can adjust as needed.

24 hours following a workout

It's important to keep in mind that, while it's more common in people who use insulin, you can be at risk of going low for 24 hours after exercising.2,3 If you work out during the afternoon, this could lead to an overnight low. If your blood sugar is elevated after exercise, a correction dose of insulin may be appropriate, but be careful not to overcorrect.2

Research also suggests that a meal or bedtime snack that's low on the glycemic index, meaning it includes protein, fat or fiber to slow the carbohydrates' absorption into your bloodstream, may reduce the risk of an overnight low.2

Even before you put on your shoes

If you're new to exercise, or if you have additional health issues, check in with your healthcare provider before you begin.2 Think twice if you've had low blood sugar in the past day or ketones are elevated.1 We want you to be healthy, but even more important, we want you to be safe.

Interested in more fitness tips?

Explore exercise articles, recipes, and more on

See Articles

1American Diabetes Association. Standards of medical care in diabetes—2014 [position statement]. Diabetes Care. 2014;37(1): S14-S80. Available at: Accessed June 7, 2018.

2Riddell MC, Gallen IW, Smart CE, Taplin CE, Adolfsson P, et al. Exercise management in type 1 diabetes: a consensus statement. Lancet Diabetes Endocrinol. 2017;5:377-90. Available at: Accessed June 7, 2018.

3Colbert SR, Sigal RJ, Yardley JE, Riddell MC, Dunstan DW, et al. Physical activity/exercise and diabetes: a position statement of the American Diabetes Association. Diabetes Care. 2016;39:2065–2079. Available at: Accessed June 7, 2018.

Related Articles


Filed under: