Post Exercise High BS

Hello Everyone, Just a quick question. Type 1 diabetic on insulin pump. I practice roller derby which is an extreme sport. Everytime I practice my blood sugars are 300 plus at the end of practice. I do not eat before practice and blood sugars are at normal level. I think that glycogen may being dumped and turning to glucose. Does anyone have this problem and what do you do to correct it? Thought about dosing insulin in the middle of practice but I am scared since its Novolog it may make my low??

Nothing as intense as roller derby, but strenuous exercise sends me high with lows hours later. Stress cortisol hormones (adrenaline) are responsible for the highs. I eat protein before exercising & that’s helped keep things more level. I have corrected exercise highs (MDI) by injecting half my usual correction dose. If I took the usual dose, my subsequent lows that follow would be really bad.

How long do you exercise? And how long have you been doing this exercise?

I’m also T1, for 36 years. I use a rowing machine at a very high pace (1000 cal/hour) for 20 minutes three times a week. Like you I have measured a substantial increase in BG from this “extreme” exercise, but the increase is rather variable. (In contrast walking or moderate pace running aerobic exercise causes my BG to fall).

You are right that it is glycogen due to stress hormones (adrenalin, etc). This is discussed in some of the diabetes books, but these books tend to stress how to deal with falling BG from aerobic exercise. The most in-depth book is by Colberg “Diabetic Athlete’s Handbook”. It’s worth reading to better understand some of what is going on in your body during exercise, though you can get most of the info online including at Colberg’s website.

I do not use a pump but MDI. I find I can inject a couple units of insulin before I exercise without going low. You could experiment with this approach, finding the amount of insulin that works for you. But if your exercise is not consistent (I imagine roller derby must have some days when you are working harder or for longer) you need to be careful that you don’t take too much. If you did roller derby for longer your BG would likely start to fall. Also, as your body becomes better trained (assuming this is a fairly new exercise for you), you will probably find that it has less of an impact on your BG.

Because the BG impact is variable for me, I don’t try to keep my BG perfect during my exercise - it is simply increasing too far too fast. But I exercise right before (not after) I eat a meal, and balance out what I need when injecting for my meal. An advantage of exercising before my meal is that I don’t have any bolus insulin kicking around complicating things while I’m exercising.

Exercise is definitely hard to control for with T1. It is truly one of those YDMV (your diabetes may vary) things - especially since different exercises can have since different impacts on BG. But I believe the long-term benefits of exercise outweigh the temporary loss of control we experience. Good luck - just keep testing and tuning and you’ll get there.

First – I love the fact that you do roller derby! I am not surprised that your bg is high after. With a typical workout – no where near the intensity you ate talking about – your bg may drop with exercise. But I find when I intensify exercise big time – staying at optimum heart rate consistently for a good duration, my bg will elevate. Further, I have no doubt there is a huge adrenal rush and those hormones will elevate bg too. I like what Gerri recommends – it makes sense. In addition to the protein, you may want to toss in some good carbs before too. The carb protein combo has been very effective for me.

I’m not sure what Colberg says about it, but there’s an automatic assumption that if BGs are going high during strenuous exercise, and there’s a glycogen dump due to adrenaline, it must, therefore, be exercise induced. I think, in your case, you need to be a bit careful before making that assumption.

You’re practicing roller derby. Are you out there trading elbows with your teammates every practice? Are you feeling that wonderful adrenaline rush each time you roll out onto the rink? Do you have competitions and react the same way?

If that’s the case, then your high’s might just be a reaction to the good ol’ “Fight or Flight” and not, necessarily, the exercise itself. It may seem like a moot point, but how you treat the highs may, or may not, depend on what, specifically, you are reacting to.

Back in my competition days, track meets meant that I only had to run 100m and 200m and a couple of relays, hours apart from each other. Not much “exercise” at all compared to a typical work-out. But, I was so adrenaline hyped in anticipation that I’d run high most of the day and spike after races. I wasn’t on the pump at the time, but, IIRC, I had to go back and adjust my basal doses of NPH to compensate for entire meet days instead of simply dosing with short acting in response to the individual highs.

Nice, one of my friends out in California just made the team out there! I’ll third adrenaline as the likely culprit. In addition to the strenuous exercise, I’m sure there’s a lot of excitement going on!!! Keep an eye on it as your response may change over time, or even from day to day. You can try slowly edging up your basal, but be careful because you are going to be extremely insulin sensitive even though your bg is going up. If you can find any sort of pattern to the highs then you can consider setting your easy bolus (or something like it) so that you can quickly administer a tiny bolus when it’s safe after x, y, or z happens.

I am still new to this insulin thing, I just started in December. I’ve always struggled with exercise induced highs. I’ve actually been finding that having more insulin on board helps my workouts and I’ve yet to experience even a mild low in the gym. I think a lot of traditional advice on insulin regimes for exercise have been based on low steady state aerobic exercise under non-stressful conditions. That is not the way I exercise. I actually think that perhaps the extra glucose generated/released by my own body during exercise may need to be “covered.” This is never explained in books, but I’m starting to feel like that may be what I need to do.

I have the same problem sometimes (when doing something high-intensity/high-stress like a short race (5k - 10k). Usually things settle down precipitously, and I end up going low without taking any correcting insulin.

Adrenaline dump? Glycogen dump? Who knows? There are lots of strategies to try before finding one that works for you. Consider reading Sherri Colberg’s “The Diabetic Athlete” so you have a handy resource.

If it’s a glycogen dump, you might try taking in some carbs before practice. Maybe 15 to 30 g in the form of a sports drink or banana or peanut butter sandwich.

If it’s adrenaline and reduced correction dose will probably help. Start small.

It may be a combination. You’ll have to experiment for awhile to see what works best.

Good luck,


I think it is a good practice to immediately follow up a workout with post workout nutrition. I have a protein shake as soon as possible. I then try to follow up with a meal within 2 hours and cover the meal with an “appropriate” bolus. It would seem that priming your body for a race and then just “stopping” is a recipe for some big transient effect, probably involving chocolate.

Yeah, definitely agree.

It’s been over 25 years since I got the 'betes and had to deal with adjusting insulin doses for competition, but I do recall lot’s of rollercoasters for the first couple of months. High BG’s definitely made me feel sluggish and took the edge off of my performances. I tried injecting correction doses of R, but I had a severe low that took me completely out of a race at one point. So, I went to correction doses followed by popping glucose tabs to keep my BG within range. Then, messing with pre competition meals, doses of R, and popping glucose tabs. NPH was a so variable that I tried that last, but I eventually found a “good enough” management plan.

Would have been nice to have the pod back in the day.

Thanks for all your feedback. It is greatly appreciated. I exercise for 2 to 3 hours at high intensity 2 days a week (roller derby). This includes skating laps as fast as my skates will take me, practicing falls, hitting others. Lots of high stress. This is when glucose gets high. Skate 1 day a week for fun (not as intense). Work out at the gym 3 days a week with 30 mins level 10 on elliptical and 30 mins on stepper, followed by weigh training. I think that I may try to do some small adjustments to my bolus level while practicing roller derby and see what happens.

Good luck! Let us know how it works out.

Yup. Every time I exercise at moderate level, my BG lowers like it’s supposed to. But when I, for example, go on the elliptical and burn 600 calories in one hour… my BG shoots upwards. The only way that I could figure on fixing it was to drink lots of water during intense exercising. If you’ve got a pump, maybe you can increase your basal a tiny bit during practice. The only way I could stop going high after working out was to lower the intensity of my regimen.