Closed loop systems and exercise

I don't have a pump but would be curious to hear what you bolused for breakfast (and what it was), how long it was before your walk, and what exercise mode on your pump actually does.

I'm guessing you had a method that worked for you when you were on MDI, it would be interesting to compare, though we do change (as you mention) and not least habituation to exercise.

I wonder if the exercise mode needs to be started earlier so you have less insulin on board when you start walking.

lol @ diabetic athletes comment - they also have a team wandering around with insulin and snacks (which I'm guessing you don't - I didn't have team car following me on my ride today either!) and it seems very hard to obtain any information about what they do (insulin quantities when on or off training and for event days, etc,, along with what BG they run at, etc., etc.)

Sorry you had a rough day @emshee1 Tagging @Juicyj who exercises with a hybrid closed loop pump, and may be able to help you.

emshee1 said:

Thanks for getting back to me, I’m feeling a bit better (less frustrated than I was earlier).
I had about 40grams (weetabix) carbs at breakfast and had 1 unit novarapid. Activity mode on pump suspends insulin but I think you are right that I should have turned that on earlier than I did. I also should have started out my walk with a higher BG, it was 13 when I started walking.

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I'd definitely need to eat if I walked 7 miles, so while I would also reduce bolus (or just do none if I were leaving for the walk pretty sharpish), I'd also have snack and be munching en-route!

emshee1 said:

When on MDI I would also have taken less insulin for breakfast, there is something different about the pump though that seems to make hypos faster? Maybe constant drip of insulin?

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When I was typing my response I was also wondering whether there's a difference between novorapid as a basal drip vs e.g. a lantus. One assumes they should be the same (for a given active dosage), but I don't know.

emshee1 said:

On reflection actually going hypo isn’t a big deal, Iv lived with this for a while. The problem is that it makes me fearful and as a result I over corrected. So fear of going very low and the fear of going very high.
Thanks for your reply. I have dusted myself off and will be out again tomorrow for a walk although not 7miles!

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The one positive with exercise-induced lows is that when you stop you don't tend to go any lower (or at least it stops dropping pretty quickly) but it does mean you need snacks with you.

With that said I do find it quite easy to go low without noticing if I'm walking - though I don't tend to walk for the sake of it, but rather because I need to be somewhere so I'm probably distracted and probably also have bolus on board.

Which pump are you using @emshee1 ? I'm using a tandem tslim which does have an exercise mode, though I confess I rarely bother with it because the pump's exercise mode tries to keep you running between 7.5 and 10 and I don't find that works well for me.

But exercise affects us all differently so if it's giving you a crashing low (oh how I hate hypos) then hopefully there is something you can do to your pump settings so as to reduce the hypo risk.

If you were losing your libre signal was your pump losing it too? When my pump loses its dexcom signal it can no longer fend off hypos because it doesn't know that your bg is going down, so I wonder if that was the issue for you? With my tslim on walks I tend to pull it out every so often to check what my bg is doing, so I know if the signal is lost. And the signal to my phone is almost never down so I can check my bg on my watch, which picks up my bg from my phone as long as I have internet phone access (which I don't have on long remote walks but at least the reading is on my phone.)

Do you set your basal rates manually on your pump? Am wondering if you could actually set the basal rate to be lower during a walk ? (Disclaimer, not medical advice, just something I would do if I was having this issue on my tslim, which requires you to preset different basal profiles.) But different pumps have different algorithms so I think it would pay you to talk to someone with the same pump as you, maybe your pump rep and of course your pump clinic.

Good luck.

emshee1 said:

Hi all, not sure what I’m looking for here? Advice/safe space to have a rant maybe. So if your reading this then thanks for giving me that space.
I wondered what others experience is of Closed loop systems and exercise.
I set off today on a 7 mile walk, bolused less for breakfast, used activity mode. Blood glucose absolutely crashed, so quickly( Libre 2 o think let me down today as signal kept coming in and out and finger prick readings were out by what Libre told me when it did actually work) , middle of nowhere and as a result felt very scared, over treated my hypo and ended up with a blood glucose of 25, so all in all a horrible vicious cycle of fear and panic! That something terrible was going to happen to me. Also felt physically ruined.
I have had type 1 since I was 4, currently mid 40’s and feel like I just can’t get a handle on it anymore. This never happened when I was on the old nova pens with act rapid and insulatard, I defo don’t want to go back to that but crashing hypos and if I’m honest the fear is starting to interfere with the things I like to do.
I am also wondering if my age, female and hormonal changes could also be behind this sort of new difficulty.
Iv have always tried hard to fly the flag that diabetes doesn’t stop me but it bloody well did today. If anyone points out there are Diabetic Olympic athletes out there I may thrown a massive hissy fit!

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exercise mode may not be good enough for some people infact its not for me.. what you can do is create a separate pump profile for exercise that you switch into, then return to your normal profile afterward, this way you can significantly lower the basal rates.. I would NOT suggest a basal rate of zero as you need some insulin to prevent ketones nut you may find a 30 to 50% reduction helps. only other option might be to carry a snack bar of some form and eat it a third of the way through

emshee1 said:

I am also wondering if my age, female and hormonal changes could also be behind this sort of new difficulty.
Iv have always tried hard to fly the flag that diabetes doesn’t stop me but it bloody well did today. If anyone points out there are Diabetic Olympic athletes out there I may thrown a massive hissy fit!

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Thanks @Hopeful34 for the tag.

I am 52 - perimenopausal and run/gym most days so hope I can help..

Firstly do not let this experience discourage you, it's always a learning experience, I have been there many times and had to overcome the feelings of fear and despair to overcome this mindset by learning something each time I hit a wall with hypo and glucose control. I was riding a road bike but almost ended up in a ditch during one hypo so stick to exercise where I am in more control of my BG levels if they do start to dip. I was on MDI and now use a tandem slim with control IQ, I tried using exercise mode but it wasn't enough to overcome lows so now about 1-2 hours before intense exercise and with a duration of longer than 40 mins I turn off the basal completely - I also ensure I don't have any quick acting insulin in my system, so if that's a morning routine then i'll eat low carb so no need for insulin, if it's evening then I will eat dinner but take only around 25% of the insulin needed and still stick to low carb - less insulin means less room for error and hypos, I find evening exercise harder as any insulin pooling under the skin will release during evening exercise, I run with a running club and peel off from the group if I see a downward arrow at 6 mmol/l as i'll know further exercise will result in a hypo and I then can steady myself out from there.

I also have a golden rule of starting exercise at 9mmol/l or above so I have a decent buffer for the duration. Also be careful if you've had a hypo in the previous 24 hours before exercising as this too can impact control.

Start with something less challenging so maybe a 3-4 mile walk, rebuild your confidence, I use Strava to track my activity as it has a beacon on it too - so hubby knows where I am in case something does go wrong. it's vital to exercise particularly for women during menopause due to losing bone density with hormone depletion and great for our mental health too.

Juicyj said:

I was riding a road bike but almost ended up in a ditch during one hypo so stick to exercise where I am in more control of my BG levels if they do start to dip.

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I don't want to derail the thread, but was this pre-CGM? I'd hope that riding a bike is no worse than running/walking, and in some ways better as you can potentially take more food/get to somewhere with food if needed. I say this having run out of food and then ridden hypo the last leg home, but it would probably have been worse needing to walk (I've also done the "going hypo while walking" many times). I do get the fact that when focusing on something it can be hard to notice hypos - this goes for all pursuits though - I used to find it quite often when working and writing analysis code (in a state of flow as they say these days), though also playing rugby or doing martial arts. I've only really been riding a bike since I've had a CGM, though I do try to listen to my body and often pre-empt the CGM if I think I'm dropping (and it eventually catches up with the way I'm feeling.)

SimonP78 said:

I don't want to derail the thread, but was this pre-CGM? I'd hope that riding a bike is no worse than running/walking, and in some ways better as you can potentially take more food/get to somewhere with food if needed. I say this having run out of food and then ridden hypo the last leg home, but it would probably have been worse needing to walk (I've also done the "going hypo while walking" many times). I do get the fact that when focusing on something it can be hard to notice hypos - this goes for all pursuits though - I used to find it quite often when working and writing analysis code (in a state of flow as they say these days), though also playing rugby or doing martial arts. I've only really been riding a bike since I've had a CGM, though I do try to listen to my body and often pre-empt the CGM if I think I'm dropping (and it eventually catches up with the way I'm feeling.)

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Unfortunately no, I was using the G7 but due to the lag of around 20mins it was moving too quickly to report accurately and I started losing my vision and awareness so knew I had to get off it as quickly as possible, it shook me alot and this combined with the state of the roads and a tumble put me off, so more of a combination of factors than just the hypo alone, I was using glucose in my drink for quick absorption but still having had a few hypos out cycling so just think it was safer for me and other road users to not ride !

I'm using Omnipod & Libre2+

Not perfect, some days better than others. One thing I've done is tweak the correction factor, more aggressive during the evenings/night time when I'm not as active and more relaxed during the day.

Like any system it takes a while (for you both) to learn.

Sometimes I will “waste” a drop of insulin before exercise. I disconnect from the site and then give a small bolus. This stops the loop from trying to correct higher blood sugars you might have if you have taken a small snack to help from dropping low or if you start with a higher blood sugar.

If you started your walk at 13mmol then the loop would have been giving corrections as you were walking.

Hi
I am dead lucky as my body works well with a combination of background insulin and walking.
My control is good with MDI and i average 15000 steps per day and just graze to keep me level.

I just wanted to say even after 50 years of injecting and knowing my body well and a hba1c of 39 or 5.7 i still make mistakes!
And will continue to do so.

I overtreat hypos like you wouldn't know and sometimes gorge myself as that feeling when you are teetering on THAT edge is sooo grim.
Again i am lucky enough to have never passed out!

I deal with all this and am ok with it and again i feel i'm just a bit luckier than most.

You are not alone and i wish you well.

Tony