Running with T1D and blood sugar crashes

I love to run, but oftentimes when I am on longer runs, I find that my blood sugar crashes ridiculously quick. I typically just carry a package of fruit snacks with me since that is how I typically treat my lows, but I find it kind of a hassle to have to hold it the entire time. I was wondering if anyone had any tips on this, whether it’s how you carry a snack/drink with you or something you do beforehand. I tend to try and dose very lightly or not at all for a snack before running but I can’t seem to keep my blood sugar from crashing. I also disconnect my pump while I am running so I don’t receive any insulin during this time either. Any suggestions would be greatly appreciated!

Running does two things: it causes your muscles to use up glucose and it also makes your insulin more effective.

The way I deal with it depends when I am running. If I run first thing in the morning before breakfast, then I will suspend my basal insulin for 20-30 minutes before the run. If I run during the day, then I will make sure to give only half my normal bolus for the meal prior to the run.

In general, the key is to make sure your basal is being suspended 20-30 minutes BEFORE you run. If not, whatever insulin is in your system will become amplified.

1 Like

@cjwillenbring hi Cydney,

2 things you have to watch out for when you are in aerobic exercise: insulin on board and basal insulin.

IOB is a function of your last meal or correction bolus, and it stays active in most people for 4 hours. (your mileage may vary). IOB means there is still insulin left in your body and increased activity beyond your normal activity will drop your blood sugar more than you think. When you calculate your carb ratio, you essentially figure out how much insulin takes care of how much sugar… for a given activity level. change the activity level and you blow up the equation. If you need 1 unit for an apple while sitting behind a computer… that same unit may cause a crash if you are running.

for me and for example, if I am exercising within 4 hours of a meal I use much less insulin for that meal.

Basal - just like @Zale said basal is the amount of background insulin you need - based on your typical amount of activity, and not having to do with food. my basal needs vary greatly with stress and if I am sitting or if I am on vacation or just more active. If I am chasing the kids at a picnic, or riding my bicycle, my basal needs drop to about 20% of typical. If I am sitting on an airplane… by basal needs go up to about 130% of typical.

so when I am going to ride my bike for an hour or 3, I definitely watch my meal bolus (I typically use less than half my normal bolus) and I drop my basal rate to 20% of normal about 40 minutes before a ride,. if I do this and the stars align, my blood sugar doesn’t crash, at all, and I don’t need a gallon of gatorade.

if you inject Lantus or other basal insulin, you’ll have to guess 24 hours before and it is much trickier. this is the main reason I pump.
cheers good luck.

1 Like

For my long runs (14-20 miles), I typically eat some protein before I start (a slice or two of microwaved ham on toast is quick and effective) and dial down my basal by 50% in an effort to put my BG on an upward trajectory. Typically, it heads up for 6-10 miles, then starts to fall faster than if I weren’t running. At that point, I typically have some Gatorade gels or a Cliff bar and that levels me out until I’m back home. I carry the snacks in the pouch of a hydration belt in which I’ve replaced the original water bottles with two bottles of apple juice (my backup plan just in case). That’s worked well for me. I rarely need the apple juice, but it’s worth carrying for peace of mind. One last tip - don’t pour the apple juice into the bottles that come with the hydration belt. It’s almost impossible to clean those bottles sufficiently, and they quickly become icky. I use hockey tape and a rubber band to keep the apple juice bottles in the hydration belt holsters. Good luck figuring out what works best for you, and keep on running!

1 Like

I find it hard to run and eat something that requires chewing, so have found Peter Rabbit Organics Banana Mango and Orange fruit puree. They have a twist off top and are super easy to manage on the run. You can find them at your local grocery store in the baby food isle. With 17 g carbs of real fruit per package, they give me a nice boost without a rebound.

1 Like

Try this — eat a small carb – one or two saltines, with a bit of fat-- peanut butter or cheese. The fat should make the snack last during your run, keep you from crashing.
Experiment with quantity of each relative to distance, time, exertion. Good luck!

1 Like

My daughter is a track and cross country runner. She was diagnosed November 2017. It was definitely a learning curve for us, but she has found that if she eats a 1/2 - 3/4 protein bar before a run it sustains her. She wears a dexcom as well and carries her phone on her, if she gets a fall alert she’ll eat 1/2 an Airhead. She is still on injections right now, so this is what we have found works for her.

1 Like

I’ve had great results with Bonk Breaker bars and Hammer bars and drink mix. Both contain complex carbs that metabolize slower than other energy/protein bars.

1 Like

Another idea would be to suspend the basal insulin 2 hours before the run. Allow your BG to rise up high. Then, when you are all finished running, you can always take boluses to lower it, if it remains too high. This would be far safer than passing out during a run or getting a stomach cramp from drinking or eating while running.

1 Like

@cjwillenbring 2 hours on an extreme trail ride… 105 mg/dl not bad for a guy turning 53 this week!

reduced basal to 20% about 45 minutes before, kept it low for 1 hour after.