Yes, you can exercise with type 1 diabetes, and it is also highly recommended. The key is managing your glucose levels properly before, during, and after exercise, because physical activity usually lowers blood sugar, although depending on the type and intensity, it can also raise it. With the right precautions—measuring your glucose, adjusting insulin and carbohydrates, and carrying fast-acting sugar—a person with type 1 diabetes can take part in any sport, including competitive sports.
Below, we explain how exercise affects glucose, why some sports lower it while others raise it, how to prevent hypoglycemia (including delayed hypoglycemia that appears hours later), and what you should always carry in your sports kit. This is general information: any insulin adjustments should be prescribed by your medical team.
How does exercise affect glucose in type 1 diabetes?
Exercise causes the muscles to use glucose, so, as a general rule, physical activity lowers blood sugar levels both during and after exercise. This effect is beneficial, but it is also why glucose must be monitored closely: without the proper adjustments, this drop can turn into hypoglycemia.
However, not all exercise lowers blood sugar. In some cases, the opposite happens, and understanding why is essential to avoid surprises.
Aerobic and anaerobic exercise: why one lowers glucose and the other raises it
The glucose response depends largely on the type of exercise:
- Aerobic exercise (running, swimming, light cycling, brisk walking): tends to lower glucose because the muscles use sugar continuously. It carries the highest risk of hypoglycemia.
- Anaerobic or high-intensity exercise (weightlifting, CrossFit, sprints): can temporarily raise glucose. Intense effort releases hormones such as adrenaline and glucose stored in the liver, which raises blood sugar during and immediately after exercise.
That is why a strength-training session may leave your glucose higher, while a long run may leave it low. Understanding how your body responds to each type of activity is the foundation for managing it properly.
The risk of delayed hypoglycemia after exercise
One of the most surprising things is that a drop in glucose does not always occur during exercise. After a session, especially if it has been long or intense, the body replenishes the glycogen stores in the muscles and liver, and to do so it continues taking glucose from the blood for hours. This can cause delayed hypoglycemia, which may appear several hours later or even during the night.
That is why it is important to measure your glucose after training and before going to bed on days when you exercise intensely. A continuous glucose monitoring system is very helpful here because it allows you to see the trend and anticipate a drop. To keep the sensor secure through sweat and movement without it coming loose during activity, many athletes use sports patches for glucose sensors.
What to do before, during, and after training
Good glucose management around exercise is based on these general guidelines:
Before training
- Measure your glucose. If it is low, take carbohydrates before starting; if it is very high, consider waiting according to your doctor's advice.
- If the exercise session will be long, increasing your carbohydrate intake at the previous meal or dinner can help replenish glycogen stores.
- Consider your active insulin: exercising with a large amount of insulin in your body increases the risk of hypoglycemia.
During exercise
- During long activities, measure your glucose periodically and keep fast-absorbing carbohydrates close at hand.
- Always carry fast-acting glucose (gel or tablets) in case you notice symptoms of a drop.
After exercise
- Measure again when you finish and several hours later, especially before going to bed.
- Replenish carbohydrates and protein to support recovery and reduce the risk of delayed hypoglycemia.
The type 1 diabetes athlete's kit
Always prepare a bag with the essentials for training or competing safely. A good kit includes a glucose meter or sensor, insulin, fast-acting glucose (gel or tablets), glucagon for emergencies, a carbohydrate snack, and water to stay hydrated. If you play sports as part of a team, letting your coach or a teammate know that you have diabetes and how to respond to a low is a simple and highly effective safety measure.
Is it different with type 2 diabetes?
Exercise is beneficial for all types of diabetes, but management is not identical. In type 1 diabetes, because you depend entirely on external insulin, balancing insulin, carbohydrates, and activity requires more adjustments and monitoring. If you want to understand how the two types differ and why their management varies, we explain it in our guide to the difference between type 1 and type 2 diabetes.
Take care of your diabetes with Glucody
Exercising with type 1 diabetes is not only possible, but can also improve your health and glucose control when done thoughtfully. To achieve this, keeping close track of your glucose during activity is essential. At Glucody, we are a brand specializing in diabetes, and we develop accessories designed for the active daily lives of people living with it, from patches and armbands that keep your sensor in place while you train to glucose gels and tablets for quick action when your glucose drops. Our goal is for sport to be a source of well-being, not worry.
