I have been managing Type 1 diabetes for the past five years, and recently I’ve stepped up my exercise routine with jogging and strength training. However, I’m having a tough time keeping my blood sugar levels steady during and after workouts.
No matter what I try, my blood sugar seems to go on a rollercoaster, making it hard to stick to a consistent exercise plan. I’m looking for tips and strategies from others who’ve dealt with this.
I’m especially interested in:
Pre-workout snacks or meals that help keep blood sugar stable.
The best ways to monitor blood sugar during different types of exercise.
Insulin dose and timing adjustments that have worked for you.
Hi Alberto. Not knowing anything about your current management plan, workouts, goals and results I’ll just throw out there that for a T1D exercise will always go better when you can plan ahead for the workout. I like going first thing in the morning so I have a known and minimal insulin on board and no to minimal food on board. Even with the best planning there will be some days a workout just doesn’t work. One of the T1D endos over at TCOYD tells a story of being on the treadmill at the gym and drinking a coke to try to keep his BG from crashing and having the internal debate of “is the workout worth it if I just consumed all the calories I was trying to burn.” Happens to all of us, minimizing how often it happens is hard work.
Are you also asking about handling a post breakfast BG rise that doesn’t match your carb and bolus calculation? Personally I have to add 20% to my breakfast bolus to handle a wicked case of dawn phenomenon.
Hi @alberto78 .
Do you do fingersticks, or use a CGM? A CGM will be very helpful for you to see where your numbers are, and they adjust every 5 minutes, so you can see how your solutions are working.
And are you on injections, or do you use a pump? A pump allows you to adjust your insulin - even pause it if necessary - for your workouts, although figuring out what works best takes some trial and error.
And
@alberto78 , this is a “how to fit exercise” I was taught in cardiac rehab. I was wearing a Tandem CIQ with Dexcom CGM.
Each of us is an individual. We each process carbs, fats, proteins, & other nutrients differently. We respond to environmental and psychological things differently. Our bodies metabolize differently and use insulin accordingly.
BACKGROUND: My personal experience with exercise is my foundation. I was about 6 weeks into CIQ when I was in Cardiac Rehab. There the full team (nurses, EKG tech, exercise physiologist, cardiologist, family, my endocrinologist) analyzed by body’s reaction to activity. Detailed measurements were made watching my cardiovascular and diabetic responses to closely measured activity. After 6 sessions, a set of foundation values were calculated. The remaining sessions built on the foundation values. I now know how I will need to prepare for physical activity. It was not easy arriving here. Integration of EXERCISE ACTIVITY into glucose management is a team effort. I had a 10 member team during most of my sessions and used G6, t:Connect, Clarity, & Sugarmate simultaneously.
RECOMMENDATIONS:
[1] Have an exercise CGM spotter.
[2] Start with a comfortable CGM report, like 140mg/dL ( 7.8 mmol/L).
[3] perform a measured exercise - use watts as your units of work since they are consistent, for the most part, across exercise machines.
[4] Note the changes in your CGM report with LIGHT EXERCISE using the calculated watts.
[5] Continue increasing your EXERCISE to build your CGM data compared to your watts expended
[6] Build a formula or guide using extrapolated glucose level behavior vs watts expended for yourself.
[6] Once you have moved to a heavy or high watt expenditure, move to those exercises, free weights, etc without direct watt metering and note the CGM response so you are able to extrapolate effort to your body’s state.
Hi, this topic requires a lot of reflection. You eat blood sugar surges you take a shot and you have to wait for the shot to assimilate and reduce blood sugar. I have found that you can work out after a meal, even if you compensate with the shot, but be aware of food assimilation rate and the shot assimilation rate. For instance, eating with a 100 blood sugar taking a corresponding short term shot at the same time and then working out for an hour to an hour and a half. Then take a blood sugar and act accordingly. Constant monitoring makes this much more understandable. You will learn that exercising without recent food could be tough. Peaks and valleys are way of life and any belief that a flatline is possible is wrong. Just be aware of when you’re planning for a food blood sugar surge then work out. Sorry for such a long message .
I have 2 children ages 6 and 8 with T1D. My son who’ 6, has been diagnosed since the age of 3 and has the Dexcom connected to his Omnipod.
There’s a feature alot of caretakers don’t know about on the Omnipod which is Activity Mode.
Endo has suggested I put on activity mode 45 mins-an hour before physical activity. This helps the pump slow down the release of insulin and recognizes you being active. In most cases,with the glucose readers connecting to a pump, it would help the pump store your patterns and refrain your sugars from going on a rollercoaster.
My daughter however was just recently diagnosed in April 2024. She is currently on injections and finger pricks until first week of November. When she’s going to do any form of active, I give her protein (it can be a shake, yogurt, peanut butter etc). I then check her sugars; if her sugars are lower than 300 no correction (even though her order calls for a correction over 250). This not only gives her extra carba to run around with but the protein that was given before hand will slow the this blood sugars from dropping.
Protein can help stabilize blood sugar levels by slowing the release of sugars into the bloodstream and blunting the absorption of carbohydrates. Protein breaks down into glucose more slowly than carbohydrates, so its effect on blood sugar levels tends to occur gradually over a few hours. When paired with carbohydrates, protein is three times more effective than fat at moderating blood sugar. For example, you can try eating dessert with or directly after a protein-rich meal to prevent a sugar crash.
hi @alberto78 , T1 makes us have to “trial and error” our way through exercise and, well, basically eating but no despair! you can do it.
I spent many years on shots and the only way for me to exercise was to cut my long acting shot. I simply can’t move if I take my long acting as if I am gong to be sitting down all day.
fast forward to pumps, on my manual pump I would use a temporary basal of zero (0) for over an hour and then use a temporary basal according to how vigorous the exercise. If I ate anything and had “insulin on board” I would have to drastically cut that bolus or eliminate it.
now on an AID feedback pump there is a thing called “activity mode” but the pump is still dumb as a rock so if I intentionally drive my BS to 180, I have to turn off this mode or the pump will give me juuuust enough correction bolus for me to go low once I start exercising. All this fancy gear and it still isn’t perfect. I was just at the Jersey shore for a week and, due to being very active, I cut my overall daily insulin use by 75% I used activity mode, but only AFTER my initial drop in BS after I started exercise, then it worked fine. so this last week: turn off CIQ (tandem specific talk) then temp basal to 0, then wait for the drop then activity mode. FYI boogie boarding and bicycles will be my plan if I have to conserve insulin in the future. I always always have carbs (on my bike a Gatorade is enough) because sugar happens, and you need to have access to carbs.
the point is to try, then observe and figure out, then adapt and try again - what will work for you may be significantly different. cheers and good luck!
Hi
I’ve had type 1 for 53 years. I have a CGM & pump and set it to activity mode prior to leaving the house. You didn’t mentioned how you take your insulin.
I think the biggest solution for me is to turn my pump to activity mode prior to leaving my house for the gym and /or long walks. If I forget and have too much insulin on board I end up doing a more low energy work out and consuming gummies or lifesavers while meandering on the treadmill.
If you are doing weight training, that can sometimes come back to bite you after working out with high glucose levels.
When I do any weight machines or free weights, I do the tread mill before I leave the gym.
Does this always work, NOPE but I’ve learned which snacks help and when to say when. I agree that it can be very frustrating but trial and error is the cornerstone of type one diabetes.
I know this doesn’t completely answer you questions but it just an insite into what works for me.
Keep up the exercise and keep notes on which foods and timing and intensity of your workouts
@alberto78, I don’t like to eat during activities so I’ve found it best to carb up before the activity. It was trial and error for me, and it will be for you, however here is what I do in case it helps you. Note that I’m on a CGM and iLet pump.
For high intense exercise (racquetball) I carb up to 180-190 BG and disconnect my pump. After 1.5 hrs of activity I end up at 75-85 BG 30min after playing. To carb up I eat twice the number of carbs in the meal before exercise and dose to half the meal size. Then I pause my pump at one hour before playing so no autocorrect or basil doses occur.
For medium intensity workouts (aka pickleball for me), I eat a 15g carb Kind bar with no pump meal announcement, if at 130BG or below, and disconnect my pump. If 150 or higher I’ll eat a Atkins carmel chocolate nut roll bar and disconnect my pump before I play. After 1.5-2hrs of playing, and depending what my BG is I’ll either connect my pump (if 140 or higher) or wait to connect my pump after I get home and shower (if 130 or less).
I don’t carb up for low intensity workouts unless I’m already low. In which case I’ll eat a handful of carbs before the activity and keep pump connected but don’t take a dose.
Hi Alberto. I have an Omnipod insulin pump, which allows me to set an activity feature for exercise. It is set to decrease insulin given in various time increments, to cover what may happen with blood glucose lowering, while I exercise, which I do daily. Do you have an insulin pump? Can you check with your treatment team to see if it has a similar feature? I use glucose tablets for lows, as they are readily available, easy to take, and low in calories. I do have to say that since I have had my Omnipod 5, which does adjustments for me for highs and lows, I have not had many lows with exercise.
@alberto78 you did not provide any specifics as to what type of exercise you are doing.
As a T1 of 52 years, and someone who has been physically active my entire life, there are some simple lessons I have learned:
Over the course of my life, I have seen changes in how exercise affects my BG. I have always been involved in endurance aerobic exercise; but as I have gotten older, how my BG responds both during and after exercise has changed.
Different forms of exercise will affect your BG differently. Strength training will affect you differently than aerobic activity. Also the form of aerobic activity you do will have different effects on your BG - high intensity short term aerobic exertion versus lower intensity long time endurance aerobic exertion. With that said, different forms of exercise will have unique requirements for both fueling and insulin.
There is another factor that a fair number of T1 people experience when doing endurance aerobic exercise is a rapid rise of BG immediately after you finish a workout. There are very few studies on this, but the little information out there seems to suggest that a rise of cortical hormones from aerobic exercise will result in BG rise immediately after a workout. This is something I experience every time I exercise, and I need to take a small bolus right after I exercise. I still live by MDI so I just take a shot before I get in the shower after exercise.
Now I can offer answers to 2 of your questions:
Best way to monitor BG during exercise? If you want to be able to know your BG at anytime while exercising, the only way to do that now is with a smart watch that can display your CGM value. There are multiple choices for smart watches out there, and I do not know the details of all of them and if they are all capable of displaying your CGM value. One sure fire solution is the Dexcom CGM and a Garmin watch. I know Dexcom worked with Garmin (and I think one other sport watch company) so that their sport watches will display your CGM value.
Insulin dose and timing:
This is a highly subjective topic. What works for me, might only work for me and no one else. So I will not provide any insights as to how I manage my insulin dosing. What I will say is that time of day will have a large effect on the insulin and fueling you need, based off natural circadian rhythm and your personal insulin schedule (pump versus MDI and long acting/short acting insulins). The takeaway here is that if you currently are exercising in the morning before you start your day, but at some point in the future need to change your daily schedule and then are exercising in the late afternoon or evening, your insulin and fueling needs will be different. If you change your exercise schedule, pay attention to the changes in your BG so you can adjust accordingly.
