Need help managing blood sugar for competitive swimming

I have a newly diagnosed 15 year old. He is a competitive swimmer and is having trouble keeping his glucose levels up during his 90 minute practices despite eating uncovered carbs before and during practice. We would love to find a snack that can hold him through his practice so he does not need to snack in the middle and miss part of practice. Any experience or advice would be appreciated!

Hello @crallh and welcome to Type One Nation.

At the risk of being obvious: carbs makes your blood sugar go up, insulin makes your blood sugar go down, exercise can increase the effectiveness of insulin by at least 2x.

Swimming is one of the most rigorous exercises possible, I would expect your son to need very little insulin while swimming.

Please consider talking to your endocrinologist and/or CDE and get a strategy for swimming. I would expect your son would need very little insulin for practice and for meets. I don’t know if he takes long acting plus short acting insulin, or if he has a pump, but there are strategies for whatever kind of insulin he is currently using.

I use a pump and so for rigorous exercise I reduce basal insulin 45 minutes before the exercise. I am also very careful with the insulin I might take with a meal if it is going to be within 2-3 hours of the exercise. by reducing my insulin, I do not experience massive drops in blood sugar and I can exercise.

there is a great book called Think Like a Pancreas, great handbook for concepts and strategies.

Cheers, welcome, and good luck.

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Our 12-yr-old daughter is super-active (cycling and swimming, mostly, plus an annual triathlon), and it can be done, with both injections and pumps. The CGM is great, obviously, but she competed before she had one of those, too: we just tested before and after, and of course if she felt low in between it did mean a break.

As for what snacks work best, the standard advice is a carb with some protein or fat to slow it down: peanut butter crackers, cheese and crackers, nuts and raisins, etc. Your son will have to experiment to find what both keeps his sugar up and is compatible with hard exertion.

The thing that most surprised me was how many carbs exercise burns through. On a long bike ride, her Tandem with Control IQ will have been giving her zero basal for hours and she’ll eat granola bars and drink Gatorade just like everyone else — taking no bolus at all — and she’ll still go low sometimes.

But everyone is different, not only from each other, but even from themselves over time. A few years ago, she was on shots, and what worked for her then was reducing her long-acting by just one unit and cutting her boluses in half.

Or at least, that was what mostly worked. Insulin, carbs, and exercise are only three of the many factors that influence blood sugar. That means every decision is necessarily just your best guess, and sometimes we guess wrong, whether because of stress (both good and bad), a growth spurt, fighting off an illness, or even the weather, all of which also influence insulin needs. So we do the best we can.

If you search this site, you’ll find lots of threads on what works for different people wrt exercise. Here’s one, just for example:

But the bottom line is exactly what @joe said: Talk to your endo, expect lots of trial and error, and congratulations to you and your son on his being such an athletic kid!

I used to cycle 50-60 miles. I went to a local store that caters to triathletes. The owner is highly knowledgeable about fueling for long efforts. He was a great help. I found a combination of gels, bars, and drink mix worked best. I preferred Stinger Gels, Bonk Breaker bars, and Cytomax drink mix. All have a combination of high protein and slow absorbing carbs so they won’t spike bg right way.

Granted, eating and drinking on a bike ride is a lot easier than during a 1000 meter swim. As a side note, my daughter, who is not diabetic but would experience low blood sugar during soccer practice, had some success with lentil beans 30-45 minutes before practice. High protein and high carbs. She hated them and still does, but they did the trick.

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Thank you. He has been trying to eat prior to swim but no matter what he eats his blood sugar drops. Then he ends up needing to eat mid practice and after practice and he feels sick from eating so much. We are going to try experimenting with gatorade or gels - this weekend he tried 2 glucose tabs b/c he was low and needed to get in for a race and that helped his bs stay more reasonable so thinking the degree of exertion might require more simple sugars than he has been trying.

I appreciate your feedback.

You may be on to something with the straight sugars. I’d easily believe he needs that much ready energy for what he’s putting out. Let us know how it goes!

This might be a useful resource for you:

I hope you and your find the right combination of things