Diabetics who run Marathons!


Diabetics who run Marathons!

Diabetics who run Marathons!

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Comment by Jerry Nairn on September 15, 2014 at 1:19pm

Hi, Brian,

Yes, sometimes it's not possible to do all of the things we talk about doing to get our blood sugars right during a run. Your run yesterday is an example.

I had an afternoon run yesterday with similar issues. Maybe I was just luckier, or maybe I handled it a little differently, but my blood sugar wasn't perfect either, starting at 157 and ending at 240.

The important thing, I think for both of us, is that we got the mileage in and we're here to discuss it.

I knew I had too much insulin on board before starting, my run, so I had a glass of juice, and took lots of carbs with me.

My Dexcom sensor had just timed out, so I wasn't getting readings there. I carried a meter with me, and I was still around 170 at the turnaround, and still worrying about my meal bolus, so I ate a gel.

So I was at 240 when I finished 7 miles. Not great, but I think it was better than erring in the other direction and going low.

When people say it's hard to manage exercise with diabetes, I almost always point out it's hard to manage eating, but we still do it. Exercise is that important. We do what we can to keep our blood sugars in line during our runs, but as long as we don't hurt ourselves, we should consider it successful.

In your case, I might have tried to take in some carbs when my bg was at 150 with two down arrows. Maybe you did. Whatever. It worked out.

Looks like it's time to change your battery.

Comment by Brian on September 15, 2014 at 6:31am

Jerry thanks for your feedback. These were some suggested training tips I received from someone local here in Denver. He's not on this website. I think the idea to minimize insulin on board before exercise is a good idea but not always easy to put into practice. Yesterday, I went for an 8 mile run. I wanted to do a morning run after breakfast so I didn't wait the recommended 2+hrs after taking a meal bolus to begin my run. Instead I reduced my mealtime bolus then went for a run. The attached photo is the typical problem that I run into since being on a pump.

I think maybe should I should have eaten a little closer to the start of my run and taken a little less insulin. Timing these things just right can be tricky. And maintaining steady BG on a long run is even harder... I'll keep tweaking my strategy.

Comment by Becky on September 13, 2014 at 1:52pm

Thanks everyone. That is a great idea for the sensor to be on my arm. I find that sometimes it is good to put my infusion sites on my arm. They tend to stick better and since the weather is getting cooler, it doesn't stand out as much. I think that I have been super dehydrated hence the nausea. Still a little nauseous today but since I am forcing myself to drink more, I am starting to feel more like myself. I will try wearing the pump next week for my long run. I feel like it is adding more bulk. I don't have enough pockets for all my supplies. :( Do you all wear packs or the belt? Where do you fit everything?

Comment by Jerry Nairn on September 12, 2014 at 2:25pm

Hi, Becky,

I wear my Dexcom sensor on the back of my arm, up near the shoulder. That works OK for me. If the sensor is on for a while and feels like it might come loose, I have a few cut off sections of tube socks, and I can pull one of these up over my arm covering the sensor and holding it on.

For a marathon, I will usually put in a second infusion site in case the one I'm using comes out, which has happened a couple of times.

I have also ended up carrying a CGM sensor that has come out during a race.

Things happen. It's always best to carry a meter.

DEA is probably right about your nausea, especially if it was a hot day, or if you know you didn't get enough fluids and electrolytes.

Comment by Carlos Candela on September 12, 2014 at 1:46pm

I do agree with DEA. I do keep my pump and the CGM while running. I was having issues with the sensor at early stage of training but was able to find an area little bit higher and closer to the belly button (But not too close) that the sensor has been staying put for the duration of the longer runs.
I do adjust depending of my sugars readings. Also I do not carry a meter during the training runs but I do during the events. I do not really know why, but more often than not the variation between what the sensor reads and how I feel is higher during events and races. Be aware of the location of the medical stations/tents. They are happy to help and they normally have a glucose readers in hand. Do not be afraid to ask them and use them. It might take 30 to 40 seconds but at least you will have a reading that you can use to make decisions.
So far I have only had a scary situation in one race that forced me to actually stop (not even able to walk) due to a low while the sensor was reading normal. Take fuel, put the pump on suspend and waited and waited. But was able to finish the race.
So prepare plan A, B and C with the additional if everything fails use plan D. Wish you good luck with your training and your goals.

Comment by DEA on September 12, 2014 at 9:36am

Hi Becky,

BG might rise during endurance exercise because your body is tapping your glycogen stores. My sense is that this causes BG rises after stopping because the BG from the glycogen release is still extant in the bloodstream but the muscular activity to burn the sugar has stopped. Once you hit 15-20 miles, your glycogen stores deplete (varies by person), and so you are not getting the BG boost from that source any longer. I'd also suggest that the nausea might be from dehydration/electrolyte depletion. I get that around 18 miles or so unless I really replenish my fluids with a good, electrolyte-containing beverage or two. Particularly during the warmer months, keeping as hydrated as possible and keeping your electrolytes replenished is a tough, but necessary job.

As for tips: I use a run/walk interval method that helps keep my BG in a more level state over the course of races of 10+ miles. I started a marathon with a BG of 55 in January and was able to get through it without keeling over my loading up with fuel at the beginning and using a conservative interval. I've never used Lantus, but I was wondering if the pump might be better because you can suspend insulin delivery if you need to during the race?

Comment by Becky on September 12, 2014 at 9:03am

Hi everyone. I am training for my first marathon. I have always stuck to 5 & 10k's which are fun but my best friend wanted to check off a marathon on her bucket list and talked me into it. We are now doing the Rock & Roll in Denver on Oct 19. So far, it has been going well. I usually take off my pump and give myself a couple units of Lantus to help throughout. I have now been running longer distances such as 18 - 20 miles and my blood sugar is starting to rise along with it. I ran 18 miles yesterday and my BG went low for the first time. I have also been super nauseous since last night. My BG has been between 80-130 since the run. Does anyone have any tips? Since this is my first marathon, I am muddling my way through. I have had problems with the CGM sticking to my skin but am going to try it again this week and see what happens. Also, anyone know of any running groups in Denver? I have read some of the blog entries and you all are my hero's. Super excited to learn from you all!!

Comment by Jerry Nairn on September 10, 2014 at 10:40pm


These two things conflict:

1. "humalog/novolog ‘peak’ 60-90 minutes following injection"

2. "Suspend insulin pump for duration of aerobic exercise lasting less than 2 hours (may have to replace 50% or more of lost basal upon resuming the insulin pump)"

Item 2 above makes sense only if your goal is to end your run with an insulin deficit.

Just as an insulin bolus really takes effect between 60 to 90 minutes later, the insulin you are not giving yourself by suspending your pump during your short runs does not matter until after the runs.

Suspending your pump for short runs doesn't make sense because it doesn't affect you during the run. Suspending your pump for long runs is a bad idea because it limits the fuel you can take in during the run.

However, we're talking about less than two hours of a reduced basal rate. If your normal hourly basal rate was 0.6 u, then you reduced it to 0.3 for your run, and you went for a 90 minute run, it is a difference of 0.45 u of insulin, most of which will not even make it into your blood stream until after the run.

So if you want to suspend your pump, go ahead. But you shouldn't imagine it is a safety thing about preventing lows during your run.

If you are going to have a low, it is from insulin that is already on board, not from basal insulin during the run.

There are definite benefits of having some insulin in your system.

Principles 1 and 3 from your post are good advice that many have shared in one way or another in this forum over and over. Principle 2 is interesting, but not so much about how to manage diabetes.

I would add, as other things to do to prevent lows:

1. Test before, after, during. Wear a CGM if you can.

2. Carry a source of fast-acting carbs.

3. Wear Medic Alert clearly identifying you as type 1 diabetic on insulin.

Is there a reason you don't want to identify your trainer? I'm curious who it is.

Comment by Caroline S on September 10, 2014 at 6:34pm

Brian- thanks for those tips from the trainer. Very clear and sensible. Sorry you keep having issues with BGs on the run, one way or another.....don't we all? Treated a low before running last night and ate some extra carbs, thinking the tempo pace would keep it lowish. Post-workout I was 332....gah! So that's why I wanted to lie down on the side of the road....

Anyways, I wonder if your issue on Saturday was the combination of decreased/no basal plus reduced meal bolus. Also, was it an easy long run or were you going fast? That could definitely make a difference. Hope this weekend is more even!!!

Comment by Brian on September 10, 2014 at 3:40pm

I met with a diabetic running training yesterday to discuss the issues that I've been having with maintaining normal BG while exercising on a pump. He provided me with some really good info that I thought I would pass on.

Principle #1: mimimize insulin on board when starting a workout: humalog/novolog ‘peak’ 60-90 minutes following injection. So, wait 2+ hours after a meal bolus to begin a workout. On the insulin pump status screen, I never start a workout with more than 1.0 units of active insulin.

Principle #2: basic endurance responds more to training VO2 max: mitochondrial density increases up to 300% with training, whereas VO2 max increases 20-25% with training. When in doubt, add a 60-minute easy run or 90-minute easy bike ride, not an interval workout. VO2 max gains plateau after 6-8 interval workouts – don’t overdo these workouts. When in doubt, shift the interval workouts back 2 weeks in the plan below. Leave the tempo runs alone, they build mental toughness.

Principle #3: insulin sensitivity will change (increase) with training and will decrease with ‘de-training’: basal insulin rate will probably go down during a training cycle, CHO ratio may go up during a training cycle, and both will probably return to pre-training level quickly following cessation of training. It’s important for individuals with T1D to keep track of how their insulin dose parameters change with training – some people may not follow this pattern.

Methods to avoid low BG during exercise

Prior to exercise: main idea here is to minimize insulin on board but to have a BG level 150 mg/dl or below at the beginning of an endurance exercise session…

Suspend insulin pump for duration of aerobic exercise lasting less than 2 hours (may have to replace 50% or more of lost basal upon resuming the insulin pump)
Set temporary basal rate of 20-50% of normal beginning 1-3 hours prior to exercise through duration of exercise
20-30 minutes of resistance training prior to endurance training has been shown to decrease likelihood of low BG during endurance training in T1D subjects
Eat 15-30 grams CHO 1-2 hours pre-exercise with 50% bolus for CHO content, or less

Decrease meal bolus prior to exercise by 20-40%
During aerobic exercise: glucose uptake by exercising muscles is independent of insulin, so most individuals can safely exercise with BG levels in the normal range at the beginning of exercise, as long as there is not a high degree of residual recent bolus insulin…


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