Q: When our son has football practice his blood sugar tends to go low, but when it’s game time, it spikes pretty high. Why is this, and how do we respond?

A: Playing a team sport is a wonderful way for kids, including those with type 1 diabetes, to keep fit and stay active. However, as you’ve already picked up on, managing blood sugar can be tricky depending on whether it’s practice or game time. Fortunately, there are some basic explanations as to why these kinds of highs and lows happen and many practical steps you can take to help your son keep his numbers within range.

For starters, when kids engage in moderate physical activity, such as after-school sports practice or gym class, blood sugar can drop low during or just after exercising, because physical activity at this level tends to increase insulin sensitivity. That, in turn, makes the body more efficient at using sugar. This is one of the reasons why it’s important for a child with type 1 to check his or her blood sugar before starting sports practice and have access to snacks and low blood sugar supplies.

When children with diabetes are physically active for prolonged periods, another drop in blood sugar can occur about 8 hours after exercising. On your part, this means keeping a closer watch on your son’s blood sugars overnight. Many parents have learned to plan for these kinds of blood sugar drops by increasing their child’s carbohydrate intake or reducing insulin doses prior to exercising — or just after. Your care team can give you guidance on what measures are appropriate for your child.

When it’s game time, competitive sports can cause some blood sugar changes that require special handling. There seem to be two factors in play here. First, short bursts of intense exercise, such as sprinting towards the end zone in a football game, have been shown to increase blood sugar levels and cause an increased need for insulin. In a person who doesn’t have diabetes, the body simply releases more insulin to help transfer glucose into the muscle cells. In a person with type 1 diabetes, that internal insulin response isn’t available, and so blood sugar levels tend to climb, often quite dramatically.

It’s also normal for kids to feel keyed up and excited on game days. Most of us have heard of the “fight or flight” stress response that occurs in our bodies when the brain perceives a challenge. The adrenaline released in those situations causes more fuel (glucose) to be made available for handling that challenge, sometimes even before starting the exercise. Again, in a child without diabetes, the body can simply release more insulin to handle this surge. In a child with diabetes, blood sugars can run higher.

Considering all the factors at play when kids engage in sports, trying to dose insulin correctly in these situations can be a challenge. High blood sugar corrections may ultimately drop the blood sugar very low, but allowing blood sugars to run really high during a game situation isn’t a great idea either! Extra fluids and small insulin adjustments may help. If your child wears an insulin pump during a game, you may need to make adjustments to the basal rates. Again, it’s important to talk these situations over with your diabetes care team.

Whatever plan you come up with, expect that some trial and error may be necessary, along with lots of blood sugar monitoring before, during and after exercise and sports (including overnight), before you figure out what works for your child. Using a continuous glucose monitor for a few days may also be very helpful for keeping track of highs and lows.

So many people with type 1 diabetes have learned to compete successfully at a very high level in sports, including pro football player Jay Cutler, quarterback for the Chicago Bears! No matter what your son’s future athletic dreams may be, with a little extra monitoring and adjustment, he should be able to stay on the right track.

–Paula Jameson, M.S.N., A.R.N.P., is a certified diabetes educator and program coordinator at Florida Hospital for Children in Orlando.

How Other Parents Deal

“My son’s basketball coach last year had the players do things like positive visualization and focused breathing before their games. He told us that players perform better when they’re calm. Well, you know what else performs better when calm? My son’s blood sugar numbers! The breathing and visualization helped lower his stress, which definitely helped with those adrenaline-induced highs.”

–Kristen G., mom of 16-year-old David

Related topics:
In the Spotlight: Sports and Type 1 Diabetes
People in the Know: Sports and Blood Sugar
People in the Know: Self-Care at Sports

See more People in the Know questions and answers >

Disclaimer: The information in these articles is not intended as medical advice. Families should check with their healthcare professionals regarding individual care.