I really screwed up swimming this week and I’m not sure what I did wrong.
I swam for about 25 minutes in cold water. When I got out and checked with a meter it read the dreaded LOW. A first for me. I felt ok but was shaking quite a bit. Either from the low or the cold? A glucose gel popped me back up enough for another swim a hour later without more carbs.
My breakfast was large(50 carbs) but that was 5 hours previous. I ate 10 extra carbs 30 minutes before the swim and put my Omnipod 5 on activity mode 1 and half hours beforehand as well. I was 125 on dex at the start.
Can the tail end of a meal dose act so aggressively in the 5th hour?
Of course swimming in general will make your BG drop. You did all the right stuff as far as eating your carbs and not swimming with IOB (like you waited 5 hours). And extra carbs before starting and all of that.
But the problem with those automated pump algorithms is that they are always reactionary.
So you ate carbs 30 minutes before starting and your BG is starting to rise. What does the pump do? It doesn’t know you are going to get in the water soon. It sees your BG rise above the target, so it gives you more insulin.
And when in the water, what if your pump can’t communicate with the CGM? (Which I think is hard in the water.) It will just go back to your normal basal amount, right?
I suggest doing it manually. It will take testing to figure out the right setup, but I suggest starting with a few things.
Always swim without IOB. I mean, even if it means skipping your meal. If you wait 4-5 hours after a meal, that’s fine. But don’t swim close to a meal when you still have IOB. (You did this, which is correct. Just make sure you continue this).
Before getting in the water, and the time leading up to it - test, test, test. Get an idea of what your BG is doing. The CGM has a delay, so testing gives you a very good and accurate idea of your BG, as long as you are using a good meter. (Use the Contour Next!)
A few carbs before you get in is a good idea, just like you did. So keep doing that.
This is the important one! Do a manual basal adjustment. I suggest turning your basal off completely for some time before you get in the water, and all the time you are in the water. (That’s fine for a 30 minute swim. If you are going to swim longer, you may need a small percentage of basal running. But that’s something to address later, for now just try to get the general setup figured out, and do zero basal. After that, we can work on different scenarios depending on other things that are happening.)
Lake swimming would be slightly more work. While it might not have major currents or waves it still is more topsy turvey? So you might have worked just a little harder than normal. And then burned through more fuel initially.
I run into that as conditions in the ocean vary. I carry gels with me I that I shove down my suit and I wear a Libre that I can scan to keep track of my BG levels. And yea, that cold feeling can either be from being cold because cold water sucks body fuel/temp from you pretty quickly, but it can also be from your BG level dropping and I find it pretty hard to tell the difference between the two out in the water.
Even with our warmer water here some wear scuba vests to keep their body temps from dropping when they go out farther or longer.
I use a Dexcom as an everyday CGM and a Libre for swimming. The Libre has been a blessing because I carry the reader in a waterproof pouch and I can scan it while I’m actually swimming. So I wear both. That allows me to stay safely out for 2-3 hours at a time. I can just down some gel while out there if needed. But the Libre won’t work in really cold water.
I never thought of gel pack in my suit but it would totally work and is a great idea. I wouldn’t the expense of a uncovered libre but I would like one for sure.
I put a couple in a small baggie. That way if I only want to down part of one I can, plus putting a partially or completely used one doesn’t make a mess shoving it back down into my suit.