Q: We’ve found that different sports affect our son’s blood sugar differently — he can play ice hockey for an hour and his numbers are the same or even a little high, but if he swims for a half-hour, they plummet. Why is this?
A: Exercising and playing sports can be incredibly helpful for children with type 1 diabetes in so many ways. However, what you’re noticing with your son’s blood sugars — that different forms of physical activity seem to lower or raise his numbers in the short-term — is a completely normal response, and it can usually be corrected with just a little extra monitoring.
How can exercise lead to a high? Physical activity or sports that require frequent start-and-stop motions or short bursts of physical exertion — such as hockey, sprinting, power lifting and sometimes basketball and tennis — are typically considered anaerobic activities. During anaerobic exercise, the body triggers the release of stored glycogen in order to keep up with these energy bursts. However, if not enough insulin is present at the time that extra sugar enters the bloodstream, the result is often a high blood sugar reading. Additionally, these same types of physically intense sports can lead to adrenaline surges that also contribute to high blood sugars.
On the other end of the spectrum, swimming, running, cycling, and soccer tend to be classified as aerobic activities. During these activities, the muscles use up glucose in the bloodstream more steadily, without the release of glycogen. With these sports, the concern is usually that blood sugar levels can fall too low.
So, how do you know which way your child’s numbers will go during exercise? Be ready to do some extra blood sugar monitoring to get a handle on how your child responds to a particular physical activity. For example, if hockey practice involves skating quickly around the rink for 20 minutes, the effect on your child’s blood sugar may be very different than playing goalie in the hockey tournament final. Keep track of this information, and provide snacks or adjust insulin doses accordingly. It’s also a good idea to touch base with your child’s diabetes care team to get their feedback on your child’s numbers and insulin needs during exercise.
Of course, there can be other reasons for out-of-range blood sugar when a child is engaged in physical activity. Does your child know how to recognize the signs of a low or high — and how he should respond? Kids don’t always want to stop in the middle of the action to check their numbers, so it may require extra effort on your part, at least at first, to make sure he gets into the habit. For most kids, staying in the game is usually enough motivation to do what’s needed to keep their blood sugar under control.
“We bring a cooler with us to sports practices that contains everything from juice to insulin. Usually, our son will have a snack before practice, and then we go from there. His coach is well-versed in the signs of a low and doesn’t bat an eye when our son sits out for a minute to check his blood sugar.”
–Reena, mom of 10-year-old Alex
Disclaimer: The information in these articles is not intended as medical advice. Families should check with their healthcare professionals regarding individual care.