Staying In Range During and After Exercise: A Real Pain in the…

If you struggle with exercise, join the club! Dr. E and Dr. P have been living with type 1 since they were 15-years-old, and even as endocrinologists, it’s a challenge for them to stay in range when they work out. However, they have some great tips on what you can do to try to avoid exercise-related lows and post-exercise rebound highs.

A Recap of Our Tips on Exercising with Diabetes for Type 1s, and Type 2s on Insulin
1. Plan Ahead!
  • The time of day you exercise is important! People tend to be more insulin resistant in the morning and more insulin sensitive at night, which means it’s harder to go low in the morning and easier to go low at night. If you’re dealing with lows, consider adjusting the time of day that you exercise – if you can.
  • Try to prepare 1-2 hours before working out. If you’re on a pump and you’re adjusting your settings for exercise, you really should do it an hour or two beforehand.
  • If you are on injections, you may need to snack a little to get your glucose level higher than normal so that the workout brings it back down without a low.
  • In terms of order of exercise, doing weights or strength training before your cardio has been shown to reduce lows with that cardio activity.
2. Adjust Your Pump Settings

Note: We don’t recommend taking your pump off during exercise. Doing so will make your body insulinopnic (low levels of insulin). As a result, when you stop working out, you create a perfect storm for rebounding high. This is because your insulin levels are very low but your stress hormones (adrenaline, glucagon, and others) are still at a high level.

  • If you’re on a hybrid closed-loop pump, you can put your pump in exercise mode, or if you’re on a regular pump you can create another program for reducing the basal rate i. Remember you have to kick the settings in an hour or two before exercise (and remember to take them out of exercise mode when you’re done working out or even a little earlier as you are finishing your exercise to prevent rebound).
  • Example of DIY Loop Settings from Steve: Steve is on a DIY loop system, and an hour before working out he changes his usual goal from 120 to 160. He reduces his basal insulin delivery from 100% to 80%, and then he puts in a time duration for his exercise settings so he doesn’t forget to turn them off. His blood sugar goal going into a workout is 150-160 with a horizontal trend arrow.
3. If You’re on MDI
  • If you’re on MDI, try to go into exercise a little on the high side. Jeremy’s pre-exercise goal is between 180-200. You can accomplish this by either snacking before you work out, or intentionally under-bolsuing for your most recent meal before you work out.
4. Make Adjustments During Your Workout If Necessary
  • You may need to make some pump adjustments during exercise. For example, if Steve is running higher than he would like during his workout, he reverts back to his usual pump settings that do NOT have any insulin dose reductions.
  • If you’re on MDI and you need to take an insulin injection during your workout, you can inject with your pen through clothes if you need to, as Jeremy always like to show off.
5. Avoid the Post-Workout Rebound High
  • Take a couple of units of insulin 10-20 minutes before you finish your workout to help get some insulin on board.
  • A cool down is critical! If you’re on a stationary bike, slow your pace and lower your incline for the last 10 minutes, or if you’re out for a run, walk the last mile home. Don’t go full throttle for your workout and then just stop.
  • If you do have a rebound high (sometimes we call them “hollow highs” because it’s the adrenaline kicking in) and you need to correct, try giving yourself half as much insulin as you normally would.
6. Don’t Forget!
  • After your workout, change your pump settings back to normal if you haven’t already.
  • Remember you can be insulin-sensitive for the next 12-24 hours after exercising, so look out for potential overnight lows, especially if you exercise in the evening. You might need to back off on your insulin if you’re on a pump to avoid that if you notice that happening.
Share what works for you in the comments below!
25 Comments
  1. I loved this video and other videos you have created in the past!

    I am a Type 1 diabetic for 20 years.

    Type 1 diabetes is so complicated. I exercise 7 days a week. I know you already know what I am about to say, but I’m going to say it again just in case.

    I’ve had my sugar at 340 before and during a 2 hour bike ride that did not return to normal levels for 3 hours, yikes. I miscalculated.

    We diabetics must take so many factors into account when exercising.

    1) Body weight – If I get too low too many times and have to consume carb items such as soda or food I am going to get fat which will not help my diabetes. It is a real juggling act to not get too low and be forced to eat something which raises weight.

    2) Exercise insulin amounts, I’ve found, depend on previous days much less current day activity. If I exercise on Tuesday I must factor in exercise and food consumption from Monday. If I had a brownie on Monday, I’ve found anecdotally it will affect my sugar level on Tuesday.

    My point for this comment is not to gain weight! Which is a tough thing when we diabetics get low because we don’t understand the myriad of variables involved with exercise, activity and eating!

    Alcohol consumption can affect sugar levels a day later for exercise or not as well.

    Best thing is just to have salad with no carb and sit in one’s room with same activity from day to day so one knows the variables but not real life where we generate so many different situations with our eating and exercise.

    Diabetes is a big math problem, right 🙂
    Thanks again for great video.

  2. Nice summary – very similar to my routine! I’m a 68 year old retired T1D since age 10. I like to cycle 2 to 3 times weekly and golf at least once a week. One hour prior to morning rides (15-30 miles), golf (~4 hours walking), or yard work, I’ll have a protein shake for breakfast (with milk and banana) and take a normal bolus. I’ll also adjust my Tandem pump as follows: 1) put control-IQ in exercise mode; 2) set my personal profile to one I’ve configured with 1/2 the basal rate I normally use. Just prior to exercise, I check my CGM and drink some fruit juice if I’m below 140 and not trending up. During exercise I check my CGM blood sugar every hour and eat a Kind bar or glucose tab if needed. My sugars (including rebound highs) vary every time I exercise – I’m used to making adjustments.

  3. Thank you! I love how you two show the reality of the “Diabetic Crap Shoot”! Thank you so very much for going above and beyond for the community.
    Cheers

  4. Excellent video as usual. You hit all the important points around the art and science of managing blood sugar around exercise. So many variables to take into consideration. The key is that you did exercise and managed to avoid a low. A few important variables you didn’t mention are your fitness level, hydration status, temperature/humidity. Thanks for all you do for the diabetes community. I love the TCOYD swag!

    • Thanks Michael, and thanks for the additional things that can have an effect on exercise. Geez how do we manage it all? I know…we are awesome!

  5. Love this app! My A1c was 8 at my first diagnosis in 2017. I am still 25 pounds overweight with an A1C of 5.5. How do I lose my weight?

  6. Wonderful vid. It’s fascinating that even “the docs” living with T1D can’t always “think like a pancreas” to manage the ptocess. It’s reassuring that we r all trying and sometimes succeeding YAY! and sometimes not. But the point is to remain self-aware and use whatever tools we have to prepare, do and reflect on exercise.

    I’ve been aiming for moderate exercise every day with the idea that my body will adapt over time to XXX moderate for ME. As I.continue, MY moderate becomes faster or with more weights or better alignment etc. And theb I ca ratchet to a newer moderate. And when I’m not feeling great, moderate will be more modest weights/pace/flexibility etc.

    Seems to work pretty well. I’m about 10 months into it.

    • Way to go, Laurie. Slow and steady (and listening to your body) wins the race!

  7. This video touches on the biggest problem I have with exercising, which is rebound highs. I use the exercise mode on my pump. I usually remember to start it an hour before I exercise, but I usually forget to turn it off about 1/2 hour before I plan on stopping exercise to help prevent a rebound effect. I also forget to give myself a dose of insulin within the last 1/2 hour of exercising to help prevent that rebound effect. There is just so much to keep track of while exercising! LOL I hope in the not too distant future, pumps will be able to learn how our individual bodies respond to exercise and start adjusting the insulin to prevent our lows during and the highs after exercising. I know pumps do help a little now, but I know improvements are in the future. Thanks Dr.Steve and Dr.Jeremy for demonstrating how difficult it is to keep sugar levels consistent during exercise. It makes me feel better about my struggles with exercising.

    • Yes, we are all in the same boat and trying to do the best we can. If you work out with your phone you can try setting an alarm to remind yourself to change settings and give an insulin dose if you need one. Just an idea…keep up the good work!

  8. The formula that’s been working for me is to exercise first thing in the morning. My theory is that with minimal insulin on board, I won’t have trouble with lows. So I get up in the morning, take 1/2 unit and a handful of trail mix before exercise, and I usually stay in range.
    What I do need to work on is not going low the rest of the day.

    • Sounds like you’re working out pretty hard, but you may have to lower your basal rate for several hours after you exercise. It’ll be trial and error.

  9. Thanks, this illustrates how difficult is it is to adjust insulin dosing (and food intake) even for experts using pumps and real-time glucose monitors. That’s where glucose-sensitive insulin may help: GSI can change the activity of insulin directly inside your system – not delayed by subcutaneous insulin dosing and subcutaneous glucose measurements. Of course, GSI is early stage research, so disappointment is possible.

  10. Loved the video; thank you gentlemen. I’m 40 and t1d since age 9.

    I exercise a few times per week. Often, it’s high intensity sports. I find I have a somewhat different experience during a 2 hour game of Ultimate where I run the equivalent of a 5k in steps, mostly sprinting during game play with breaks when I sub out for 5-10 minutes at a time or halftime.

    First, I try to make sure I don’t have a stomach full of food. Disclaimer with all this is that there are so many variables that there is nothing guaranteed. But I came here to say this, mainly: with high-intensity exercise, my sugar tends to spike during game play. I have to take insulin – often several doses over the course of 1.5 hours – to keep my sugar within range. Afterward, I usually have to eat to accommodate the stacked insulin. But it’s the only way I can avoid going 250+ during high intensity exercise.

    • Your point about spiking during high intensity exercise is a good one which I have experienced on occasion. In fact in the ‘Diabetic Athlete’s Handbook’ by Sheri (2009), it is recommended for runners to ‘sprint as hard as you can for 10-30 seconds to induce a greater release of glucose-raising hormones’ whenever you start to feel low (p39) – although I’ve found it better to take glucose tabs when trending low.

    • It’s amazing how all of us react differently. It just shows we all have to individualize.

  11. Good job gentlemen—love the TCOYD bike and walking outfits! Thanks for the advice—exercise with Type 1—ALWAYS a challenge– wish I had a real pancreas!

  12. Very interesting learning about rebound highs and hollow highs. You both are awesome

  13. Really useful videos, keep them coming!
    My daughter (teen) is the T1D in the family and I was interested by your tips in exercising because she’s a dedicated competitive soccer player and since the last year all the planning we had built across the years went out to the thrash!
    Before (Before what??? becoming an adolescent? soccer gaming style changing? (from running after the ball to wait-pass-kick)… anyway, before last year, we had a very simple tip: remove the pump 15 min before the game (and thus reduce the risk of breaking it!) and take 4-8g of sugar at the halftime. Worked 80% of the time… except if it was a big competition then the stress would keep her high so no sugar at halftime.
    But since this year, her blood sugar stay stable or even increases during the game!. We are switching gear and keeping her on the pump (normal setting) to try to counteract this… but even then the blood sugar increases and she needs to correct-bolus. We did a 3h bike ride and observed the same: we had to correct-bolus twice to keep her in range (but being careful since we are always expecting the depletion of carbs to finally show up). Also had same type of graph with swimming/playing in the pool. So I think it has to do with her body changing more than the type of exercise she’s doing.

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