Long Runs and Type 1--Nutrition During Workouts

Hi! I’m new to the site and getting all kinds of great information.

I’m interested in hearing from anyone with Type 1 who does long (1 hour plus) runs or other cardio workouts. I am currently preparing for a half marathon, and will be doing marathon training after that. My biggest problem is getting low during the run. So far, I take my pump off during the run, and bring my Dexcom so I can watch my blood sugar numbers. I take one or two glucose tabs whenever I get below 90 or so. The problem is, I have to go through so many! Last week on a 12 mile run, I went through 20 tablets, and was still getting pretty low by the end. Maybe I need something more subtantial, like gels or bars?

What kind (if any) of nutrition do you use during a long workout? How many carbs, how often, what form? Pump users, do you keep yours on during exercise? If not, is there a limit to how long you can go without needing it? Anything you could share would be helpful…


I share your pain. I just finished the Boston Marathon and consumed so many gels that I got pretty severe stomach cramps at mile 17. I finished ok, but was pretty uncomfortable.

Having said that, I take 1 gel for every 3 miles. It works for me. I never go low. I start out at 100, if I can, and start consuming gels slowly from 1 mile on. We are all different though. That’s my story for today. My stomach hates it. So, I need to find a more stomach friendly source of carbs. I the “gu” gel. Maybe something better is out there.

Anyone else have a suggestion?

BTW: finished in 3:36:25. Wanted to go much faster but the Newton Hills were hard and the stomach cramps didn’t help. Just wait till next year!

That’s awesome Tim! Congratulations! I did a couple of marathons several years ago, before I was on the pump. I used gels then too, and that’s probably what I’ll go back to this time, if I don’t get any better ideas…You’re right, though, not great on the stomach.

Hi Emily,

I have been running for a while now and just completed my first Half Marathon last weekend. I keep a blog at http://www.runningwith1.com and just wrote a guest post about what I try to do for my runs for another diabetes blogger (Tony Rose) here -> http://bloggingdiabetes.com/2009/04/running-with-type-1-diabetes/ I go into extreme detail on my guest post, so check it out if you get a chance.

3 keys. Reduce Basal prior to your run. Be careful with the amount of insulin you have on board. Carry something like GU with you.

Thanks Gary! The Blogging Diabetes post was very helpful and informative. Enjoyed your blog as well. I ran the U-City 10 mile also–good post on that! It was a fun race, despite the melting snow bombs from above. I’m doing the Bridge the Gap Half Marathon in Quincy in a couple of weeks (mainly because it was quite a bit less expensive than Go! St. Louis), and am hoping to do NYC Marathon in the fall (will see if I get in via the lottery).

I will definitely try reducing my basal ahead of the run, and I went to Fleet Feet yesterday and grabbed a bunch of gels, bars, and “sharkies” to try on my training runs over the next couple of weeks, to see what works best for me.


U-City was a fun run. VERY small world, eh? Just under 400 runners and you and I were 2 of them. :wink:

Hi Emily,

I guess this is one of those never FULLY solvable dilemmas. I just ran my first half-marathon yesterday – in 90 degree weather, yikes! The big thing that I’m always concerned about is that pretty much all organized runs start early, like 8 or 9am. I have problems when I get up early and have to eat right away, which I definitely had to do before that kind of run. I was really concerned that I would get a big spike in my blood sugar from the early morning eating, but I lucked out yesterday and it didn’t happen. I usually reduce my basal 45 minutes before the start of the run to 50% and leave it at 50% until about the last 15 minutes of the run when I put it back to normal. I do something completely different for shorter, faster runs, but this seems to work for me for longer, slower runs. I usually eat a gel about every 5 miles, plus drink gatorade throughout the run. Yesterday I was 71 shortly before the run and ate a gel, then at mile 5 I was 77, and ate another gel, and at mile 10 I was 107… finished the race at 102. That felt pretty damn good.

Even though they don’t offer it at any races that I’ve seen, I have incorporated Accelerade into my long runs from the suggestion of another Type 1 runner. It’s a sports drink that also has protein so the absorption isn’t quite as fast. I usually carry a water bottle of it with me, along with gels and a glucose monitor. I prefer the Honey Stinger gels, but I think that’s just what I’m used to.

Good luck with your upcoming races!

Thanks for the info, Cait! That’s great that your race went so well. I tried leaving my pump on, at 50% on my long run this weekend, and it went pretty well. I took some gels along the way, and was able to keep pretty stable, so I was happy (much better than the glucose tabs!). I think that’s what I’ll do for the race as well. I might look into the Accelerade you mentioned as well. Thanks for responding! :slight_smile:

Aaagh! DO NOT turn off your pump!!! Do you see any other runners leaving their pancreas in their cars? NO! the reason is that you’ll have no insulin (zero, null, zilch) in your blood two hours later. Since BG often goes up after strenuous exercise, that’s begging for DKA. This is the voice of experience talking. (Deep rumbling thunder sound here.)

You need to account for the two hour peak time of most fast acting insulins.

To help avoid lows during a long run (I’ve done 2 marathons, two halfs and am training for another half) reduce your basal rate starting about 1.5 to 2 hours before starting your run. Return to normal right after the run. How much to reduce is a matter of trial and error. I cut it by 50%.

I start my runs with a slightly elevated BG, almost to 200 sometimes, but over 150. Check BG every 30 minutes. Add carbs at about 120. If under 100, add carbs and slow down or take a walk break - just be careful.

Carbs that work for me are glucose tabs, gels and a diluted sports drink, like Gatorade. Drink a LOT of the diluted sports drink while you run, it hydrates and adds carbs. Grab any carbs offered by volunteers along the route, especially pretzels. Love those pretzels. The sports drink, though is my most important source of carbs during the run.

Test every 30 minutes, if you don’t mind me saying it again. If you’re using a CGM, pay no attention to the number, just to the trend line and watch for quick drops. Don’t fret about the ups.

Keep up the good work.


I started running less than a year ago and have done a 5 and 10K. I tried using the gels and cubes but did not like them. Now I lower my basal to about 50% and eat raisins if I get below 120.

Ha ha! Yes, I’ve been good–no taking my pump off except for shorter runs (under an hour). I ran the half-marathon last weekend, with the pump at 50% from 2 hours before the race, which worked out perfectly. Started the race at about 170, and it came down to the 130s-140s for most of the run. Used a couple of gels at about mile 7 and mile 10, and that seemed to do the trick! I didn’t test during the race because my numbers weren’t close to being low, and I’d tested right before (also the overall trend was quite even the whole time–no big ups or downs), but I did have my meter with me in case I needed to check.

Thanks for the advice and encouragement!

Awesome! Good work Emily.

Thanks Gary! The race in Quincy was a great one–you’re in IL, right? I’d definitely recommend it–a nice flat course with just a couple of hills towards the beginning. The weather was pretty close to perfect too–in the mid-60’s at start time with a few clouds that burned off by the end, but never got too warm. I ran it in just over 2:15, which was slightly more than my goal of 2:10, but I’m still pretty happy with that. Now I’m just waiting to see if I get a spot in the Nov. NYC Marathon…fingers crossed!

Hi Emily,
I too am a long distance runner and a T1. I’m not on the pump. I try to run all of my long runs in the mornings. I don’t take any short lasting insulin before I run and I try to start my runs a little high (over 120 but under 200).
When I run in the evenings I make sure to be at least 4 hours with out insulin.
For lows I take dried dates - a higher GI than sugar. I don’t think you need gels for any thing under 10 - 13 miles. and the gels don’t do all that much for your BS.
If I were you I would disconnect you pump a few hours before you run and start a bit high.

I don’t eat anything during a run and have had very bad experiences (including almost stopping a half marathon because I mistook dehydration for a low). Before I ran a marathon I ate 1 banana a half hour before the start.

bananas before and after

Echoing what most have said, keep your pump on with reduced basal levels, consume carbs during the runs and watch for the post run affects on your BGs for up to two days. I go on very high intensity three-plus hour group bicycle rides, and after the two hour mark, it seems like I just can’t consumer enough carbohydrate. I take one GU gel every 45 minutes which is 20 grams.

I wear my pump but drastically decrease my basal rate. Depending on the time of day that the long workout is occurring, my basal rate will be as low as .175. I need that insulin when working out for maximum performance. I would not go without it.

And any intense exercise beyond an hour and a half has an effect on my BGs for up to two days. I find that a hard two hour ride will require a decrease in basals for 24 hours and a hard three-plus hour ride will require my basal rates to be affected for 48 hours. Watch for this.



I’m running my 2nd marathon on Thursday. last time I used 3 gels and I take dates in case I get low.
Last time I ate a banana 30 minute before and I started out with BS of 150+. I usually start a long run with BS of 130-190.
If anyone has any suggestions I’d be happy to hear them.

hi, i’m brand new to this group, but this is a decision process i go through almost every day. my doc isnt wild about my practice, but i fuel before my runs, unless i’m already above 180. and yes, i carry Gu everywhere i go. i then Gu every 45 minutes as needed. it may sound like a hassle, but think about normal folks out for a 10 miler that have no idea what condition their body is in; we always do!

i guess normal is relative… some might think running 10 is insane!

Mike, i just saw your post. i do exactly the same thing, 130 to 190 is perfect for me. i Gu because i know exactly the number of carbs, but it is tough on your gut. just remember your h2o. have fun on your 26.2 run, i look forward to hearing about it.

I’m so glad I found this question Emily. I was diagnosed T1 about 10 months ago and I’m training for my first half marathon and my first 6-mile run is today. It sounds like everyone does pretty much what I do which is comforting to know. I’m soooo sensitive to exercise, sometimes I have to do a temp basal to do chores. When I’m running I’ve found I have to reduce my basal rate by 75%! And still generally I sip about 30 grams worth of carb (Gatorade) during an hour long run to stay around 100. By sticking with the gatorade, I haven’t found I have tummy problems yet. But for the full half I’m going to want to carry some Gu.

One thing I like to do, I mix up my own Gatorade from the powder so I can set the concentration. What you could do is take a couple extra bags of the powder and then refill your water bottle with them at a water station and mix it up as you run off. That way you’re not carrying a full 13 miles worth of Gatorade with you from the start, along with all your supplies. I feel like a dork with my huge fanny-pack, but I can live with being a dork, and I can’t live with being dead (literally).