Swimming and extream lows

Does anyone else get fast drooping BGs from swimming? My daughter got lows in the low 50s from swimming.

hi @Type1Cat well swimming, like all vigorous exercise, is good for you, and counts as cardio exercise. Now if she has any insulin in her (IOB, active insulin) then that insulin can work much harder resulting in low blood sugar. if she has a basal rate that was set while she was doing “average activity” then it is much too high for swimming. A higher than necessary basal rate can drop blood sugar.

I think you should consider taking your observations to the doctor or CDE, and come up with a swimming strategy. This strategy will likely be: reduced basal, timing of meals and adjusted carb ratios right before swim. (or dance, or run, or ironman contest, etc.)

If I am sitting at my computer then 1 unit of insulin, for me, will help me metabolize about 8 grams of carbs. Now If I go do something strenuous, that same unit of insulin can metabolize 20, 40 and even 100 grams carbs (depending only on how hard I am working). Sometimes I can’t help it and have to drink sugar (gatorade, full sugar, is my goto for workouts), but if I know in advance, I don’t have to eat or drink a lot of carbs for a workout. good luck.

Thanks! Helpful information!

Long before I had T1D, I always needed to snack and rest after casual recreational swimming. An hour lifesaving training class or dive would wear me out. I spent several summers swimming, then snacking, snoozing= and repeating.

Just being in water a body loses 800x as much energy as in the same temperature air. Swimming in water that is a tenth of a degree C below body temperature, you expend energy at about the same rate as moving your arms and legs at the same speed as when running.

If you were to folllow the “wait an hour after eating to swim”, you would have very little glucose in your bloodstream and gut to power your muscles. When that runs low, your liver starts providing some. Continue doing it and you’d “run out of steam”. As you get chiled, BG will try to rise, ketones wll rise and many of your organs slow down-to conserve energy- including your pancreas. You’d feel weaker and tired and eventually pass out and drown. Water survival training for persons without diabetes is to float shallow, move as little as possible and hope for a quick rescue. For us with it, survival time is shorter. Be smart and don’t over-exert in the water. Start “high” take frequent breaks and check.

Karen, I want to suggest a book for you: The Athlete’s Guide to Diabetes by [Sheri R. Colberg]
It goes in depth into understanding exercise and Type 1 Diabetes and what happens in the body. I got into life threatening situations with exercise and couldn’t find a way to do any exercise safely until I read this book. Now I’m sprinting and hiking 12 miles. None of my healthcare professionals ever told me what I read in that book, and I doubt they even knew about it. Hopefully it helps you and your daughter.

It’s not unusual to have to make adjustments to your typical routine when exercising - adjusting insulin and/or having a snack; and even timing of meals and insulin for those on injections. Each person has to figure out what works for them - hopefully the book @rosorio recommended will help you and your daughter find what works for her.
There is an online article in Diabetes Self Management (an excellent resource in my opinion) on athletes with Type1 diabetes. It is recommended not to post links here but you can look it up for inspiration.

Thanks for wll the info!!!

Hi, @Type1Cat - For me, not just swimming but when taking a shower, too. For me, both situations, it comes back up again - aggravatingly, it takes about 20 minutes to fully reach a reliable level even after a 7-minute shower.

The shower version isn’t as extreme, but it’s enough to cause confusion until I was just used to it - which occurred after a T1D friend of mine mentioned it without me ever bringing it up.

At the time I was still using Dexcom and Freestyle Libre at the same time, what the heck comparing them as long as I had extra FSL after changing brands (insurance). When my friend pointed it out, I finally noticed that FSL did the same thing, and I had never realized it.

Um sorry maybe I misunderstood. Swimming for awhile will definitely lower my blood sugar. What I’m talking about is when the sensor of whichever brand is in a wet situation and starts reading lower than your BG really is. It’s been about 6 weeks I’ve been watching this now, with however many showers plus 2 days a week in PT in a pool, so I’ve had plenty of chances to see the bounce-down-while-wet-and-back-up-after. It’s consistent for me, as my friend says it is for him also.

Hi @theNoz . Heat can lower glucose - I remember warnings that diabetics should not use saunas because they could cause a drop. And I knew someone who would take a hot shower to lower her numbers. I don’t know if that works universally but she did say it helped her.

Well, @wadawabbit… I never thought of my showers as being too hot, but they’re warm enough to keep me from getting chilly.

The pool at PT, on the other hand, I have been told that I’m not the only one - most of us patients complain that it really is too cold! And that’s where I get lower temporary lowering of BG according to Dexcom than during my showers. I haven’t asked what temperature it is, though.

So how warm exactly is warm enough to lower BG? And the BG always starts coming back up pretty right away. Like, within maybe a minute of the sensor drying off.

Hmm. The only thing I can think of - and science is not my forté - is that it has something to do with circulation🤔.

What works for me, is to eat a 15 carb protein/fiber bar about 20 minutes before my exercise event (mowing the lawn, walking, etc.) The carbs give me a bump in my blood sugar at about the same time as the exercise is lowering my blood sugar. When insulin is timed right and carb consumption matches the exercise, I often get pretty flat BG’s with this method.

Can also use Tandem’s activity function, but must be enabled prior to the exercise so the insulin reduction and the exercise are in alignment.

Thanks for the info! @thequetip, I am going to probably try that idea.