Blood sugar and exercise

Is there anyway to avoid lows during and after exercise? The only thing I know to do is to turn the basal rate down before, during, and after exercise and eat a snack before, and possibly during, exercise. Is there anything else I can do? I’m guessing there is no way around eating and constant sugar checking. What do y’all do?

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try not to have any IOB during exercise
turn down (somewhere between 50% and zero, DEPENDING) your basal roughly an hour prior to exercise
Use a CGM to reduce “constant sugar checking”.
Have some protein/fat prior to exercise if you want to help level out bg’s during long periods of exercise

that’s about the only things I can add to the things you mentioned.

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That’s a good one for pumpers.

I like to walk. I’ll watch my CGM and if it starts trending down, I’ll add some small carbs, like hard candy or cough drops.


I have found that NO insulin on board is a mistake. If you were a sugar-normal, you would have insulin on board. I have my best success lowering basal rates to 18-25%. The one area I just have not been able to figure out is keeping my BG up during a very extended activity: Playing trombone in a big band.

It’s completely impossible if I’m playing bass trombone, but it’s very difficult even on tenor trombone. It’s hard to eat something substantial when you have 15 or 20 minute break. The amount of energy it takes to blow air through a tube is astonishing!

Tim, IOB is insulin still active from a BOLUS. Having IOB when very active is an invitation to a low. We aren’t talking about non-diabetics–they don’t take insulin. I’ve been at this for decades and can tell you emphatically that if I have IOB, I’m going to get low when I’m active. Not sure how you are managing your diabetes, but if you think you need IOB, then you are carbing up too much perhaps.

Non-diabetics don’t take insulin because they produce it. So it is ALWAYS on board (when they need it–without injections). My comment comes from the experience of running to an appointment for 6 months with no basal running and going low 70-80% of the time. I raised it to 18-25% and I had less lows. 18-25% of .6 units per hour is .10 to .15 units per hour.

I’m not sure how you’re managing your diabetes either, but I do what works for me. If it doesn’t work, I try something else. Someone suggested taking SOME basal when in hurry-scurry mode and it worked. Like everything else, YDMV.

NO, it (endogenous) isn’t “ON BOARD” in the sense that a BOLUS given SUBQ is “on board”. You are confused and I’m not going to give you a more lengthy explanation as I’m sure you would keep on arguing as you have already twice now. There is a vast difference between endogenous insulin flowing through your bloodstream, vs the insulin sitting just under the skin, that is slowly dispersing into your blood over the course of ROUGHLY 5 hours. THAT is what is considered “IOB”.

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Hi, Cocheze!

If I am doing a high intensity cardio (zumba, running, boxing), I usually check right before I start and if it’s below 100, I have one rice crispies (17g CHO). I like them because they are light to carry, don’t spoil, the package is easy to open, are not messy, and taste okay.

If I am doing a strength training exercise (pilates, yoga, weight lifting, CX), then I might even take 1 or 2 units before the class if my blood sugar is above 120. Some people drop during yoga, but my bg usually gets higher.

But there ARE Type 1s who still have insulin production. My Novolog is a crude attempt to replace a very fast-acting hormone that in a sugar-normal would transport the extra glucose in my blood to my body’s cells quickly. In a non-diabetic, the blood glucose is maintained through micro-managed glucose and insulin all the time. The amount is small, but it’s there.

The point the CDE was making with me to try this cut % of bolus technique is that the body’s natural state would be to have some insulin working all the time. Not a huge amount, but much like how a pump delivers basal. My basal insulin has probably never caused my hypoglycemia. My bolus of Novolog starts too slow and stays around WAAY too long. It’s the dumping of an insulin bomb in our system that causes all our problems. And robots.

That sounds like what I do. If I’m running lower, I will decrease my basal rate. Do you ever take your pump off for exercise? I would like to not have to wear it while being active, but I always go high if I take it off for a workout.

Unfortunately, I don’t wear a pump… YET. lol
I moved here from Brazil and managing my type 1 with Novolog and Levemir was the easiest way for me to transition into a new country. Now that I have my team set up here, we are already looking into getting me a pump. I’ve had type 1 for more than 10 years now and I can’t believe it took me so long to look into it. I guess I got accommodated with I already knew and didn’t want to make changes. But this week I started testing a Dexcom (CGM) and I am loving it!!! So I am definitely excited to transition to a pump.

That being said, that is why I can’t give you a more accurate advice on the pump, but I can share what I’ve been doing. For example, my doctor reduced my evening dose from 30u to 20u of Levemir on the nights that I workout. If I don’t workout, I take the regular dosage. So I guess it would make sense for you to reduce your basal, but only your doctor will be able to tell you how much you should reduce. Carrying the rice crispies and eating it before working out has helped me as well because if I reduce the basal too much, I will be high a couple hours after I workout or I will wake up with a high bg. So I rather keep the basal at a level that will keep me steady until the next day, and have a snack that will hold my bg at a safe level during workout than to reduce my basal so much that I will have a high later and have to take insulin before going to bed. Does it make sense?

The CGM is also a great tool - it makes me feel more comfortable because I can easily check during exercise if I am quickly dropping or not… Do you wear one?

The other day I did a strength training class and I was fine during class (116), finished at 139 and 2 hours later… guess what? 300. It’s frustrating, but oh well. Now I now that I can’t skip my insulin after strength training workouts. So I guess you will also find out what works as you experiment with it. But my doctor definitely helped me a lot to figure everything out more quickly than me playing lab with myself. lol

Let me know what you decided to do, I love to learn new strategies!!!

agreed. :slight_smile:

I tried a whole bunch of different things. I think we can change ourselves through exercise. When I started running (2008…), I’d just acquired a pump and would turn the basal down quite a bit, I think I’d try like 10% of normal, by the time I explored longer runs (Jan. 2010, c. 8-13 miles) but my BG ran up. I kept at it and in 2011 trained for and ran the Chicago Marathon, fiddling the whole time with different concentrations of Gatorade and basal rates. Over the next couple of years, I figured 50-75% basal worked most of the time. For 3 mile runs, I don’t touch basal but have c. 7-10G of carbs and it will cover the short runs.

I guess my point is that I like having a pump and I have found that fine tuning and situationalism are very useful!

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I’m 230 lbs right now and pumping 100 + units a day. When I was pumping 38 units a day, I was 155 lbs. At that point I considered doing 2 insulin pens therapy. I was very lean and it was hard to put the site in. I hope to get back to 155 - 180 lbs and I might consider injections but I guess no matter what your weight is the pump is probably the better choice, right?

That sounds like an anaerobic exercise effect. When I take my Body Pump class, I frequently lower my insulin pump’s basal rate to 40-50% for the first 45 minutes, then at the end of class, I will raise it to 150% for 2 - 3 hours after.

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Hi, there!!! I can’t wait to switch to a pump and learn all those tricks.For now I guess I can only try NOT to skip my novolog after the workout. I am glad to hear I am not an alien and you got the same results! lol

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After aerobic exercise (several hours+), I also increase my insulin by giving a bolus, to make up for the protective reduction in basal during my hours-long activities.

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this might help me to i been geting low when i exercise & after to.

Ever tried peanut butter. My BG was trending down and I thought I would suck on a couple of tablespoons of peanut butter. Well my BG wasn’t increasing, I thought, so I ate a sugar free jello pudding, about 8 carbs and my sugar was a respectable 93. I checked it a couple of hours later and it was 209, hello peanut butter.

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You’ll have to excuse me for not being terribly familiar with pumps (I’ve been MDI for about 10 years now), but in my case, I either anticipate and check… or not check and make an estimate on where I go. The trick for me is doing roughly the same exercise every time I go out (roughly 6km, 1 hour and 15 minutes). I might eat something pre workout, but I’m usually high in the morning and just correct when I return home with OJ. I’ve also found that if I work out multiple day in a row, I get more frequent lows overnight, but this might be harder to control with Lantus doses for those of us on MDI… not sure if it’s relevant for you.

So since you’re on a pump, I can’t really offer you any specific advice on what to do with insulin doses. One suggestion that I have that helped me was seeing a diabetic sports physiologist. About 7 years ago, I cycled to work on a daily basis, generally between 10 to 15 miles each way, and if it wasn’t for seeing my DSP (or whatever you call it!), I probably would have made more mistakes. Maybe you’ll be able to find one in your area (and hopefully your insurance covers it)! Joslin Clinic has a team of sports physiologists.

I personally don’t have anything against the pump (for me it’s a -major- contact issue), but I fare well with MDI, and others fair well with pumps. As far as insulin use and weight (100 units of insulin a day), I can say this: I was taking approximately 65+ units of insulin a day (25 lantus and 30+ humalog) and eating no more than 150g carbs a day (minus fiber, and give or take a dessert or two) this time last year. In September, I moved to Japan where I have no car and rarely take the train. I’d probably estimate on a daily basis that I’m walking on average an hour a day (sometimes it’s a necessity, sometimes it’s a workout)

Without really saying how much weight I lost (I feel like it’s irrelevant), I’m now injecting about 40 to 42 units a day and I’ve seemed to have bottomed out (although I’ll have to see what the next three months will bring). From my experience, the transition from 65 units insulin a day to 40 units a day was rough. I was going low quite often. If you’re doing routine exercise, you may find your ratios changing as each week goes by.

Best thing I can say is good luck!