The Liver: The “other” diabetes problem…
Raise your hand if you’ve ever had this problem: you wake up to a nice, normal blood sugar of, let’s say 90mg/dL. You don’t eat anything, but you lower you basals a bit and head out the door for a short workout, let’s say a 30 minute run. You come home, and your blood sugar is still in a nice normal range. You eat a zero carb breakfast, barely bolus, basals come back to normal, and you move on with your day. And then, an hour or two later, you’re up around 250mg/dL or worse, feeling like crud, and wondering why you bothered to work out or eat healthy in the first place. You bolus the heck outta that blood sugar, only to find it not budging a smidge. Lovely. By lunchtime, you’re starving from all the insulin but still barely under 200 and voila, your morning has had it’s ass kicked for no apparent reason.
Sounds familiar? Well you’re not alone. I’ve blogged many times about post workout high blood sugars and their mysterious, obnoxious ability to stick around way longer than a high caused by food alone. Many of you have commiserated on this - and these stubborn highs don’t just come with exercise - they can come from stress, from being sick, in the early morning, and even when you’re starving and expect your BG to actually be lower. Fortunately, we’ve know exactly who to blame for this particularly nasty breed of highs. Unfortunately, the solution isn’t all that simple.
The culprit of these highs is our well-recognized, but often under-represented liver and it’s chemical messenger glucagon. Let’s talk about what normal physiology looks like in a person with a functioning pancreas during the scenario I mentioned above. We, as humans, get glucose from two places: the food we eat, and our livers. When we don’t have any food on board, the liver kicks in and gives your body the energy it needs, and it’s actually glucagon’s job to make sure the liver knows “hey bro, you’re up - no food around!” Glucagon usually knows when to do this because our levels of circulating glucose, insulin, and blood sugars are supposed to be known - so in people without diabetes glucagon only works when it has to, then shuts up when liver glucose is no longer needed. So if a non-diabetic goes running and needs energy, it will get it from the liver until it’s services are no longer needed. When that person gets a meal, glucagon takes a break and no longer tells the liver to release glucose. Pretty good system, huh?
Enter diabetes. Everyone knows and worries about the pancreas with our disease, because insulin is a must-have for living - it should get first priority! But in non-diabetic bodies, the liver and pancreas (and glucagon and insulin as their messengers) are constantly communicating about what our glucose levels are, who needs more of what, and where we’re getting energy from. When we have diabetes, all communication breaks down. Our bodies still know that to get us through that run in the morning, we need glucose from the liver - we haven’t eaten, so it’s our only source. The trouble starts when the run is over. In normal physiology, as soon as insulin is being produced from the pancreas, the body sends another signal from the pancreas in the form of the hormone amylin to suppress glucagon: it’s the equivalent of your pancreas yelling down a hallway “hey, we’re good down here, don’t need any more energy - we’ll take it from here!!” The problem with diabetes is that because there’s no insulin yelling down the hallway, glucagon keeps going and going, telling the liver “I think they still need energy! I mean, I dunno? But we can’t let anyone go hungry around here! Keep going liver!”
That’s why when us folks with diabetes get in this situation, taking artificial insulin won’t help - at least not for a while. When insulin is produced endogenously, the message gets sent loud and clear to suppress our glucagon and turn off the liver. But when you take artificial insulin, it’s like the bathtub is overflowing, but all you’re doing is mopping the floor. You need another hormone to turn off the bathtub. Hence the ridiculous high blood sugars, and the inability of normal amounts of correction factor to bring them down, and the end result of being pissed off you got up early to exercise only to have crap BGs all day.
This doesn’t just happen with exercise: dawn phenomenon can cause your liver to output more glucose, as can stressful situations (ever had your blood sugar go up after an argument? I’ve watch it happen several times), or being sick. It all stems from our livers not being told by glucagon to shut down, and it can cause some MAJOR issues in our diabetes management that can’t be fixed right away by taking insulin.
So what can we do? I wish I had a simple answer. One tool is using Symlin, which is a synthetic version of the hormone amylin which in normal pacreases is released to shut off your glucagon. Symlin is an injection that you take before meals for this exact reason (www.symlin.com). Other people deal with the exercise issue by actually raising their basals a little, or delivering a small bolus mid-workout (although then the danger lies in the “active insulin while exercising issue” - which we all know can send you low right quick).
The bottom line is that we don’t talk about glucagon and our livers much, but they’re a huge source of glucose fluctuations in both Type 1 and Type 2 diabetes, and can make us say “what the heck?” when high blood sugars pop out of no where for seemingly no reason. It’s infuriating and it’s complex to deal with, and it can ruin a good blood sugar day in two shakes. Now that we’ve discussed our science lesson for the day, I’d love to know any strategies besides taking Symlin that people out there have - has anyone had success raising their basals a certain amount? Or perhaps eating something before these workouts and managing the bolus that goes with it? I’d love to know any secrets you all have!
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Comments
I’ve had some good success with eating before workouts. I don’t do anything about my basal, but I lower my food insulin dose by almost half and then workout about 30 min to an hour later. My bg goes a little on the higher side than normal but when my workout kicks in it brings it right back down. Of course, it’s a pain to have to wake up at 5am for a 6am or 630 run, but the food seems to really be helpful. Especially if you have some carbs and protein (like a slice of toast and eggbeaters).
I also eat before exercising in the morning. I usually have a bowl of oatmeal (25g carbs) an hour and a half before working out and take only 30% of my normal bolus for it.
It sounds like you’re adjusting your insulin right before you work out? I had this same problem, until I began setting a temp basal 2 hours before I ran, for say, 30 min-1 hr before running. Then, a normal basal after that leading up to the actual run, or maybe 50% depending on how hard the run was. I was setting the temp basal too late, and I think because the basal affects you two hours later, then you’re high and you don’t have a workout to lower your blood sugar.
Also, you could try bolusing a little bit even if your blood sugar is steady/low-ish, which I found keeps me even on this one too.
My life as a T2 is very different, but taking metformin blocks >90% of the liver glucagon release. Good news is I don’t go high after exercise, bad news is when I go low exercising or a meal delay there’s no ‘second wind’ response - I just crash until I get something to eat. (and you don’t want to see me hungry!!). Wonder if some metformin on workout days might help T1 to manage the post-workout highs? BTW Lexi, that’s a GREAT description of the physiology and medications.
@Rich
I don’t think metformin would do for T1s what it does for T2s (at least not all of them). Metformin lowers insulin resistance. The only significant insulin I get is from the needle. The moment my pancreas died, so did the effectiveness of metformin. It may not be true for all T1s, but it’s true for me. Whether you use it depends on whether the T1 is insulin resistant and/or overweight with an out-of-control A1c.
As soon as I’m done working out (or sometimes before I finish) I set my temp basals up to %160 for about 3 hours PLUS I will usually bolus 1-1.5u no matter what the number on my meter says. Even if I am low at the end of a workout.
It doesn’t always work and most of the time i am STILL high.
This post was fantastic and I’m totally going to share it on my blog.
Thanks so much to everyone for their great suggestions - I knew this would cause some discussion because I’ve heard so many of you struggle with this. Since I’m finding myself needing to eat before the long distance stuff anyways, I’m going to try bolusing less than half of what I normally would for it and see if that helps out. Darrell the CGM does catch the rise but a) it happens so fast it’s hard to chase it, and these highs stick around much longer than say, a food induced high BG and B) if it happens when you’re working out, you’ve got a decision to make about taking insulin while exercising which can be really tough. Excellent tips though everyone, I really appreciate the feedback!
Great post! While I am a T2 runner, I have major problems with my good ole liver. It is so overworked that my liver enzymes live in a constant elevated state. Almost mimicking fatty liver. I did not realize what would happen after running though, and your attention to this will bring my attention to testing a bit more post exercise to make sure all is coming down. I’m also bad because I tend not to hydrate and take nutrition on runs - and I don’t carb load before an endurance event, so I wonder what I am doing to my system! I am on, however, Byetta, which is Symlin’s cousin, and this has helped control my liver immensely, along with a small dose of Metformin in the evenings, which did NOTHING for my BGS control alone. I have an a1c of 5.7 also! I happed upon your blog from discussing diabetes and running last night at my group social run with Fleet Feet down here in St. Louis. I was searching for a team I could run with, and raise funds for D, and saw you! And above saw some friends I’ve known in the DOC for quite some time! Glad to see you’re out here, and I’ve followed your blog now! Thanks for keeping it real and helping me learn just yet another thing I must monitor! Jill
Jill thats so great! And you are completely on to something with the Byetta - yes, it also supresses glucagon like Symlin, so that’s an excellent that combined with the metformin it seems to be helping - glad to hear that! And so glad you found a good running group! There’s nothing better than some friends to keep you motivated 
I suspect that the rebound high is in response to the zero carb breakfast in conjunction with the basal decrease. The basal insulin doses are required to turn off the fat breakdown and the release of liver and glucose stores. The body needs glucose for energy and by not eating carbs after endurance sports to replenish the muscles the body will release its emergency stores.
I enjoyed reading this and I now understand better why my daughter goes high after her gym class. At times I give her a snack before gym, remove the pump for 1 hour and she can drop from 250BG to 76BG. Recently, though, she has been going in HIGH and staying HIGH! It’s been driving me crazy. I’m glad to read how others manage exercise & their BGs.
I’m ashamed to say it took me TWO WHOLE YEARS to figure out the pattern that after a 2 hour morning outrigger paddling practice I was often high all afternoon. What seems to work is going back to my normal basal about 30 min before the end of the workout, turning up my basals (~120%) once we’re done and then over-correcting for my post-practice breakfast. As an interesting side note, it’s only paddling that does this to me. Hiking just makes me low.