Running - how do you balance blood sugars?

Does anyone else have trouble figuring out a good blood sugar level for running? My bg tends to go too low during run if it’s below 180, but then it spikes really high afterward. It’s frustrating. Any advice?

Devon, since you’re a pump wearer, your post-run spikes could be the fault of your post-exercise basal needs. Do you set a temp basal while running? Perhaps you need to cut off the temp basal sooner after the run. Or do you mean you spike from treating the low?

Either way, I think 180 pre-run is a decent place to start actually. I’ve always found that the treadmill drops me like a rock and I need to start a little higher in order to avoid that crash. I would suggest playing around more with temp basal levels pre-, during, and post-. But then again, I am the LAST person to tell you how to exercise successfully. Maybe David Wendel or Terry Keelan or some of our more athletically inclined folks will come along behind me and answer you better. :slight_smile:

Thanks Melissa, that’s good advice. You were correct in thinking that my bg skyrockets later on from the run itself. I will reduce the time my pump is on a temp basal and see if that evens it out. Thanks again. :slight_smile:

My experience as a pumper : I walk a lot ( training for the 1/2 marathon , Disney World , Team Diabetes Canada , Jan. 2009 ) ; when I do more than 5 k I use temp. basal of 45 percent, start about 1 1/2 hour prior till about 1 hour after I plan to finish the walk ( and a bit of jogging ) …it is not unusual to have BG’s go up after execrcise and a chance to have them drop up to 24 hours later . Finger poking a must .
I also eat small pieces of glucerna bars about every 30 minutes ( bar cut in 8 pieces ) , when walking more than 10 k . I totally agree with you and Melissa to start of at a BG of 10.0 ( equivalent of 180 ) , rather than a lower BG . Unfortunately , it takes some planning …so be it .

It’s always a challenge because it’s different for everyone and it’s different day to day. I recommend that you get a copy of (and read) Sheri Colberg’s “Diabetic Athlete.”

Spiking bg after exercise is a common phenomenon. Basically it’s because you have used up all the glucose via exercise, your liver goes “uh-oh!” and starts pumping out glucose as a sort of emergency response. That’s the Reader’s Digest version. There’s more detailed information on the web and in the literature.

As for keeping the BG level - YMMV. I see you’re on the pump. Do you change your basal rate before every run? How long before? Does the duration or intensity of the run make a difference in your post run BGs?? Do you usually eat before or during a run? How long after the run are you spiking? Lot’s of variables to consider. I use a pump and here’s what I do:

I try to start with my bg a little high. Around 180 is okay. If it’s lower I might eat a snack bar or a piece of fruit to keep it up. About 15 grams of carbs. If I eat more than that, I’ll bolus for the excess over 15 g or half of the normal bolus, whichever is lower.

If I’m running less than one hour I don’t make any changes to my basal rate. If more than an hour, i reduce my basal to about 50% starting 60 to 90 minutes before the run and time it to go back to normal when the run is over. Some people don’t set it back to normal until an hour or so after the run.

The 60-90 lead time accounts for the fact that the insulin I’m pumping now won’t be effective for about 2 hours. So I’ll have a normal level of insulin on board for the next 90 minutes, but a reduced amount of insulin on board when I start my run. Timing is everything.

If running over an hour I also take some fast acting carbs with me - sports gels, or a gatorade/water mixture, or some pretzels, and start munching after 30 minutes or so.

It’s essential, IMHO, to carry a meter with you, as well as some glucose tabs no matter how far or long you are running. I try to test every 30 minutes. If I’m going low, I chew some tabs. If i’m okay or a little high, I don’t do anything but run some more.

If you find yourself spiking after runs, you might actually want to eat something within the first 30 minutes after the run to give the insulin something to work on besides the glucose you have on board.

Just some thoughts.

don’t forget to buy that book. It’s a bible for any active diabetic.


Thank you Terry for all the advice! I’m going to buy the book for sure! This was all very good advice.

You said you carry your meter, glucose tabs, and snack with you. I always have juice or some sort of hard candy I take, but I often don’t carry my meter. I want to start carrying my meter with me though. Do you carry your supplies in some sort of pack or hold them? My trouble is having so much stuff along I can’t carry it all. Do you test your bg as you run or stop mid-way? Also, do you ever have side-aches or cramps from eating while you run? Sometimes I get sick to my stomach.

Thanks again Terry for the tips, and I’m putting the “Diabetic Athlete” on my shopping list.


First, I got the One-touch Ultra, which is small, light and great for running with. If you already use a Lifescan meter this will be perfect since you can use the same strips.

I carry my stuff on an elastic belt I picked up at a race expo. I strap the meter in its pouch to the belt. I put my I.D. and some cash in the meter pouch. The belt has an expandable pouch sewed onto it in which I place my glucose tabs and keys. I wear it under my jersey to reduce bouncing and move everything to the back. It tends to stay in place there. My pump is clipped to my shorts, usually.

I don’t recall the brand name, but it might be the SpiBelt (, which, coincidentally, is a supporter of Triabetes and has a diabetes link on its website. Of course you can find a wide variety of belts and stuff at any running store and most sporting goods stores.

Another option I’ve heard of, but don’t use, is to run loops. You can keep your meter in your car or some safe place and run around to it every 30 minutes or so. That way you don’t have to carry it. Personally, I don’t want to risk being without it.

I test every 30 minutes or so, but I have to stop to test. Sometimes I can test while walking. Haven’t perfected testing on the run. I have used a CGM while running but I find the numbers are unreliable - although it will tell you how fast your BG is rising or falling. It’s saved me from bonking a few times.

I don’t get sick or cramping, but maybe that’s because I’m used to eating before and during my runs. Of course, some of those gels can make you sick just by themselves. Try eating smaller portions over an extended time OR instead of eating, get your carbs by mixing them into your water. I mix gatorade and water, but there are lots of other supplements available. Again, try your local running or sporting goods store.

Good running,