Control IQ and Exercise

I know we are all just getting going with control IQ, but I wonder if anyone else is having a lot of trouble with exercise? I work out regularly and have found that the control IQ algorithm just can’t keep up after about 30-40 minutes of exercise. I started on Control IQ a month ago and I have had to treat for lows every time I exercise. I have tried setting the exercise function on about 2 hours before I start and my basal rate is already as low as it can be programmed. I participated in the exercise clinical trials early on with the artificial pancreas at UVA and the algorithm controlled me beautifully, but now that the real thing is here I have found it to really struggle to keep up. I have actually had some of the worst lows I’ve had in years since switching over. Just curious what others are trying or if anyone else is having this problem?

Hi @lauren720 and welcome back - we haven’t seen you lately. I’ve been using Control IQ since January and have found it working okay for me during two-hour resistance workouts at the gym, but when I have extended [8+ hour] volunteer construction on weekends, I need to add in a couple of snacks. Like you, I set CIQ to exercise mode about an hour before I expect to begin activity.

I don’t recall if you have had diabetes for a long time, but I’ve found that as I age and have been using insulin, all types, for many decades, that the effect of insulin has slowed down its onset. On two of my profiles, my “Work” and my “Gym” profiles, I use a lesser meal bolus ratio - the lower I:C ratio puts less insulin in my system and appears to have lessened my sudden hypo drops. I accept this and put up with a little more post-meal increase. Probably not a medical-book approach, but an acceptable work-around for me.

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Hi Lauren. I use the riley link close loop system, which I have been delighted with. I presume it is symilar to the control IQ system as it uses a closed loop algorithm which automatically adjusts basal rate to accomodate for blood sugar change trends. The one thing to keep in mind that the biggest reduction in basal insulin is shutting it off (for mee going from .55 units per hour to 0). Like Dennis I need to snack or power gel every 30 min of exercise and have found that I must adjust my pre exercise meal bolus to compensate for the increased insulin sensitivity I have whin I exercise. It is useful to note that the impact of reducing a 3-5 unit bolus by 30% will have a much larger impact than reducing a .55U/hr by 100%. The insulin will act for 2-4 hrs depending on what type you are using so it is nearly impossible for the algorithm to adjust for a bolus that is on board from 1 hour previous.

Not sure if this is helpful but good luck with working with the new system. I am a huge fan of closed loop systems and find it a pleasure to consistently wake up and start my day with blood sugars in the normal range.

Thanks to you, and Dennis, for the feedback. I have been wondering if I have too much insulin on board from lunch that is still in my system when I workout later in the day. Pre C-IQ, I used to eat carbs (no bolus) about an hour before exercise too, but now the C-IQ will do a correction bolus if I start creeping up. So, I find I need to wait until just before or during. Lots of new things to figure out here. But, I’ve been type 1 since 1982 and am so thankful all of these advances!! I love control iq overall!

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In my eyes @lauren720 C-IQ is really awesome and it has appeared to adjust itself to match my lifestyles - provided I remember to select my proper profile before going to bed the night before. After laboring for years, I was diagnosed 25 years earlier than you, trying to keep a relatively stable BGL, CIQ has now moved my TIR from the 80% range into the 90’s.

The only weakness in the system that I encountered is the G6 failing to provide readings. Over the past two weeks, my “CGM Inactive time” has been 9 hours, 42 minutes. I spent a couple of hours on the phone yesterday with Dexcom & Tandem discussing this weakness; after listening to me gripe, Dexcom connected in Tandem. Let’s see what happens.

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@lauren720 IOB is critical for me. I use Loop, the DIY system referenced in a previous comment, which is similar in concept to CIQ, and it can’t automatically regulate for strenuous exercise, either. For me, exercise control means acting like I’m on a manual pump - what is my IOB, how many carbs on board, will carbs arrive at the right time, etc. If you use Facebook, it might be helpful to check out the Control IQ users group. Stick with it, you will get there. I’m switching to X2/CIQ soon, so I’d be interested in hearing what you learn about CIQ and exercise. Good luck!

I have had CIQ for about three weeks and I am in Cardiac Rehab, post CABG. I have found even with the Exercise setting I need to eat CHOs before rehab and then cover only PART of the CHOs in the snack. First time I missed the coverage and G6 went to 176mg/dL. Will be trying again tomorrow and will try different % of the CHOs. I am using Surgical Ensure with 45 CHOs.

I do not have trouble with exercise in Control IQ, but the insulin duration is assumed to be 5 hours, when my own is actually 2, so the Control IQ system thinks there is more insulin in my bloodstream than there actually is, and I now have many more high sugars. Also, I have to ignore the IOB figure they give, because it is wrong, when I calculate a correction bolus to take. I am still grateful for the system, so I avoid being woken up so frequently at night by low BG’s. And also, I used to forget to turn down my pump for shopping in a large store or mall, and this just works automatically, which is great.

@lauren720 - Hi - I just got my tslim pump last week and started on Control IQ and I’m having the same issue as you mentioned in your original post. Was wondering if you had found a solution that works for you these past few months since you originally posted?

My experience so far: I went on a brisk 1-hour hill walk yesterday and turned on Exercise mode one hour before. It worked great for that purpose - blood sugar was nice and level all day. But when I’ve tried to do intense exercise (30 minutes on elliptical machine) it’s been a disaster! Today, I went super low (44) so Control-IQ shuts off all basal for 1.5 hours and then my blood sugar ends up shooting up past 300. Ugh - This has happened 3 times now. I’m concerned that I’m going to have to do what I used to do with my old Animas Ping - e.g. disconnect the darn thing all together when I exercise intensely :frowning: which seems to defeat the purpose of Exercise mode in Control IQ.

@CloseLoopScott - You mentioned that reducing the bolus by 30% was more effective than shutting off the basal completely. So… would that reduction simply apply to ANY meal bolus within 2 hours or so before exercise - e.g if I have lunch at 11am (for example) are you saying that reducing the lunch time meal bolus by 30% would be better for an upcoming 1pm workout than would be turning off basal entirely (or reducing the basal by 30-40%) - is that correct/ and has that been your experience? If so, would it be best to reduce the bolus by 30% AND then NOT use the Exercise mode in Control IQ at all? Or do you still go ahead and use Exercise mode as well? Very curious!

@Dennis - I read ALL of your posts : ) so I’d welcome any of your wisdom on what you’ve learned on this topic as well these past months since the original post. Wondering how much of the crashing/ lows is based on ISF vs. timing of bolus etc.

Thanks for sharing what’s been working for you - much appreciated!