Regardless of the type of diabetes you have, regular physical activity is important for your overall health and wellness. With type 1 diabetes, it’s very important to balance your insulin doses with the food you eat and the activity that you do—even when you are doing house or yard work. 

Planning ahead and knowing how your blood glucose (blood sugar) and body respond to exercise can help you keep your blood glucose from going too low or too high.

Preventing lows

Your blood glucose response to exercise will vary depending on:

• your blood glucose level before you start
• the intensity of the activity
• the length of time you are active
• the changes you’ve made to insulin doses

Sometimes people experience a drop in blood glucose during or after exercise, so it is very important to check your blood glucose, plan ahead, and be prepared to treat hypoglycemia (low blood glucose).

To learn how different types of activity affect you, you should check your blood glucose before, during and after an exercise session. Put a trial and error system into place. For example, increased activity may mean that you need to lower your insulin dose or eat some extra carbs before exercising to keep your blood glucose in a safe range. Some activities may cause your blood glucose to drop quickly while others do not. 

If your blood glucose is trending down before a workout, have a pre-exercise snack. Always carry a carbohydrate food or drink (like juice or glucose tabs) that will quickly raise your blood glucose. It may take a while to figure out what works best for you. 

If your blood glucose level is less than 100 mg/dl before you start your activity, try having a small carbohydrate snack (about 15 grams) to increase your blood glucose and reduce your risk for hypoglycemia. This is especially important if you took insulin recently and if you will be exercising for longer than 30 minutes.  

If you use an insulin pump, you may be able to avoid adding an extra snack by lowering your basal insulin rate during the activity. And if you have repeated problems with your blood glucose dropping during or after exercise, consult your doctor.   

When your blood glucose is high…

Blood glucose can also run high during or after exercise, particularly when you do a high-intensity exercise that increases your stress hormone (i.e., glucose-raising hormone) levels.

• If your blood glucose is high before starting exercise, check your blood or urine for ketones. If you test positive for ketones, avoid vigorous activity.
• If you do not have ketones in your blood or urine and you feel well, it should be fine to exercise.

Sit less

Exercise is important for overall fitness, but so is limiting the amount of time sitting. Kids and adults these days tend to spend a lot of time in front of various screens—television, computers, video games, tablets, smart phones, etc. Too much screen time is associated with higher blood glucose levels, while physical activity is linked to lower A1Cs and healthier hearts. ADA's Standards of Medical Care in Diabetes recommend breaking up time sitting by walking, leg extensions, or overhead arm stretches every 30 minutes.

Kids: spontaneous activity and blood glucose 

The tricky part about exercise in children of all ages is that it is often unplanned and spontaneous. Will your child come home from school today and do homework for an hour or want to bike with friends for an hour? Sometimes you don’t know if your child is going to run around for 15 minutes, or run around for an hour and need extra carbs to prevent a low. 

Be prepared to give 5–15 grams of carb, depending on the child’s age and size, for every 30 minutes of sustained activity and monitor sugar levels frequently. 

Infants and children

No matter the age, you can help children stay active. For example, encouraging infants in active play to explore movement and their surroundings supports physical and mental development. For toddlers, 30 minutes or more of physical activity a day with no more than 60 minutes of sitting at a time will help promote motor skills and muscular development. 

For preschoolers:  At least 60 minutes activity per day

• Give your child 5–15 grams of carbohydrates for every 30 minutes of activity, depending on initial  blood glucose levels and the intensity of the exercise. 
• Check pre-exercise blood glucose levels in active children since a young child may not be able to verbalize the symptoms of a low. 
• Starting exercise with blood glucose in the 150–200 mg/dL range may help lower the risk of  hypoglycemia in toddlers. 
• Paying attention to your child’s blood  glucose levels before and after exercise will help

Young children and adolescents

Children and adolescents should have at least 60 minutes or more of physical activity each day. 

• Include aerobic activities such as running, swimming, biking. 
• Anaerobic exercises consists of short exertion, high-intensity movements, such as jumping and sprinting.
• Include strength training, such as yoga, weights and other activities. 

Your health care team’s role

Your health care team can help you find the balance between activity, food and insulin. When testing on your own to learn about your reaction to different activities, keep a record of your activity and your numbers. Your health care team can use that data to suggest adjustments and refine your plan. If you are having chronic lows or highs, they may need to alter your insulin dose or make a change in your meal plan.