Diabetes and exercise

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Exercise will have an impact on your child's blood sugar levels. Learn how to adjust insulin accordingly.

Key points

  • Exercise lowers blood sugar levels and makes the body more sensitive to insulin.
  • Give extra food when your child is going to exercise, or lower the dose of insulin.
  • Monitor blood sugar levels for several hours after exercising.
  • Children with an insulin pump can exercise but should take caution to protect the insertion site and catheter.

The following tips are general activity guidelines for children and teens with diabetes. Every child responds to activity differently, and some child​ren may have more vigorous exercise demands than others. Therefore, always discuss your child’s activity levels with your diabetes care team to ensure optimal diabetes control.​​

Adjusting insulin for planned activity

Most children welcome routines, but once in a while schedules can change. If you do not plan properly, the blood glucose (sugar) balance may be upset. Parents, and in time children, can learn to assess the impact of regular events. Then when an opportunity for a new activity comes along, everyone will be better able to cope with the change.​​

Exercise both:​​

  • lowers blood sugar levels
  • makes the body more sensitive to insulin.

This is why you should pair exercise with extra food. After a while, you will become more familiar with how your child responds to activity and you will have a better idea of how much food, if any, to offer. Some, often older children learn to decrease insulin during times of extra activity rather than eat extra food.​​

Here are some ideas to deal with planned activity​​

  • In general, provide extra food for extra exercise. Children need about 10 to 15 grams of carbohydrates for every 30 minutes of extra activity (that is to say, outside the usual). This could come from an apple or half a banana.
  • If possible, check blood sugar levels before and after the activity. These levels will provide important information for future activities. For example, if the sugar level is very high after an activity, then less or no extra food may be needed. If the sugar level is low, more snacks will be needed.
  • Always make sure children have enough food with them, especially if the activity goes on a long time or if it is a new or unusual activity for your child. Examples of food could be glucose tablets, fruit roll-ups, juice boxes, or granola bars.
  • If your child starts to have a low blood sugar episode, stop the activity immediately and treat the reaction. Do not start the activity again until the symptoms have gone away and your child has eaten some extra food.

How to prevent delayed “low blood sugar”

  • Monitor blood sugar levels long after exercise. Low blood sugar (hypoglycemic) events can occur up to 12 hours later.
  • Children doing activities after supper should have a bigger evening snack. Doing a midnight or middle-of-the-night (2 to 4 a.m.) check will help detect late-night “lows”. If your child has a late night low, give them a larger snack the next time your child has the activity. Once the late night hypoglycemic events stop, you will no longer need to check blood sugar levels at these hours.

Extra activity: Michele’s story

Twelve-year-old Michele has always taken her ballet lesson on Saturday afternoon. To get ready for an exam, she is planning to add an extra hour to the lesson.​​

To prepare for the change in her schedule, Michele’s parents first think about her current routine. Michele always has an afternoon snack of a fruit and a starch. The longer practice means that she will be dancing when her morning dose of intermediate-acting (NPH) insulin is reaching its peak.​​

Michele will be home for her usual 6 p.m. supper. Without the extra class, her blood sugar level is usually between 8 and 12 mmol/L at suppertime. However, her blood sugar level often drops in the night after vigorous exercise that occurred earlier the day.​​

Michele’s parents work out the following plan:​​

  • Eat an extra fruit and starch choice before her second hour of dance.
  • Take blood sugar monitoring equipment to the lesson, as well as a small juice box and granola bar, in case her blood sugar level starts to drop during the lesson.
  • Check the blood sugar level at the end of the lesson to see how effective the plan was.
  • Eat an additional carbohydrate choice at bedtime to balance the delayed effects of the exercise.

Another option would be to decrease the morning dose of NPH by about 20%. This would require frequent monitoring see the effects of this adjustment and to detect or prevent hypoglycemia.​​

Activity and insulin pump

Using an insulin pump should not be an obstacle to being active.​​

However, it is important to protect the insertion site and the catheter, and well secure the pump. Some sports equipment can protect all these parts of the pump, or your child could wear an extra waistband to secure the equipment.

Some children disconnect their pump for the duration of the activity, such as while swimming or during competitions. Ask your dia​betes team​ for advice before your child starts disconnecting their insulin pump during an activity. Your diabetes team will work with you to figure out the safest plan.​​

Last updated: October 17th 2016