Getting back to exercise!

[The_Bowlii]

It's very early days for you, so you also have the added difficulties of the honeymoon period to contend with, so don't worry. Experimentation is key though, even once you think you've got everything sorted, it (diabetes response) randomly changes in my experience, so you need to (re)start the experimentation, so you may as well get used to the process 🙂

You can calculate how high you may end up going without bolus, and decide if you're relaxed about that - taking 20g of carbs might drive my BG up 6mmol/l. It's not the end of the world IMO. Ideally I'd do without the transient high, but the only way to work out how to do it is to practice, so that's what I'm doing.

Having BG numbers available at all times and being able to see TIR at all times is probably not very helpful psychologically for anyone. It's very useful to have the data available but it can lead to attempts to overcontrol and to stress when the numbers aren't quite right, even if over a longer averaging period things are actually perfectly fine. Don't get me wrong, having BG data is useful and I'd not want to go back - for longer term control optimisation (i.e. basal rate and carb sensitivity fixes) as well as for shorter term control, understanding responses to specific foods and making split dosing decisions, but there's a fine line between this and attempting to overcontrol (ending up with stress about the values and annoying BG oscillations - I'm an engineer, can you tell? 🙂). I don't feel this is very helpful if you want to balance good BG control with leading a relatively normal life and doing normal things. Others may disagree, that's fine, I'm happy to discuss elsewhere, I like a good discussion 🙂

I tend to do at least a 1h ride most days for BG control purposes (though not this week due to rain and volume of work and my BG is running high because of that - I need to setup my turbo). This exercise means my BG is more stable and I run lower in general (and I get fitter too and probably accrue some other exercise health benefits as handy side effects). I sit in range during these rides without the transient highs caused by eating while riding (and the same is generally true for my commutes) or I use these short rides to fix highs rather than injecting a correction (though this is a "dangerous" thing as I sometimes don't bother to inject a correction expecting to go out soon, only to find someone books a last minute meeting so I've run high for no reason and still need to do the correction - setting up the turbo will fix this, Teams calls while riding 🙂).

Riding longer rides, which is where I tend to have the transient highs when I set off, is not essential for BG management, however I enjoy pushing the distances and seeing new things, so while I can't claim it has a diabetes-related physiological purpose it does have a quality of life purpose and I'm happy to trade off the transient high against that. There are no hard figures to calculate the cost-benefit trade-off between these psychological aspects and the bad effects of running high for a given period of time. If there were, I wonder if that would actually be better - more data to stress about 🙂

I feel I may have gone off track a little, nothing new! 🙂

hi @SimonP. Yes, I can absolutely tell you’re an engineer 🙂 - I’m a research chemist by training but now work in a large engineering team so I recognise the symptoms!

Great feedback, thank you. You’re correct - I spend all day stressing about levels now I’ve got the CGM Libre2 and app. TIR is around 84% over the past month which the consultant said was good but being a perfectionist has its drawbacks :-(.

Like you, I use exercise to correct highs but I do seem very sensitive. Just walked for 20 mins to catch a train and got the low level 4.5 mmol/l alarm even though I was over 7 mmol/l when I set out! No IoB so a bit surprised and sorted with a couple of jelly babies. I used to like them but I’m starting to go off them 🙂.

Cheers, Chris

 

[SimonP]

hi @SimonP. Yes, I can absolutely tell you’re an engineer 🙂 - I’m a research chemist by training but now work in a large engineering team so I recognise the symptoms!

Great feedback, thank you. You’re correct - I spend all day stressing about levels now I’ve got the CGM Libre2 and app. TIR is around 84% over the past month which the consultant said was good but being a perfectionist has its drawbacks :-(.

Yes, definitely.

Like you, I use exercise to correct highs but I do seem very sensitive. Just walked for 20 mins to catch a train and got the low level 4.5 mmol/l alarm even though I was over 7 mmol/l when I set out! No IoB so a bit surprised and sorted with a couple of jelly babies. I used to like them but I’m starting to go off them 🙂.

I wouldn't consider 7 to be high and I think I'd expect to need something for a walk (even if not rushed) to go and do something (like catch a train), vs just an amble around - it's the expectation of what I'm going to do rather than the mode of transport in many cases (going shopping will make me drop like a stone for example.)

Despite happily riding for an hour without much change in BG, just going for a walking can still cause me to drop (though this may be a trade off caused by exercise intensity - I'm getting more liver assistance when riding as I'm riding harder when only for an hour).

It does of course all depend on whether BG is rising/falling, how it has behaved all day so far, etc.

Don't worry, you do eventually get a feel for it without needing to think about it.

P.S. Yeah, I'm also not very keen on jelly babies, skittles all the way - they are carb-rich, pocket-portable (in party sharing pack sizes) and generally easy to consume.

 

[The_Bowlii]

Morning all. It’s been a busy week doing Zwift workouts and playing squash - there is life after T1D diagnosis 🙂!

Quick question - played high intensity squash match last night (lost :-( ) and seemed to get the nutrition about right with flat BG throughout. At dinner, however, despite reducing insulin, I went low (Libre said 2.9, finger prick said 3.5) so drank 200 ml orange juice to get back to normal. All ok and flat from 20:00 but overnight levels rose between midnight and 03:00 to around 12 mmol/l. Any ideas???

 

[pistolpete]

Your way more insulin sensitive after a high intense work out, up to around 2 hours. I really plan a meal and if it interferes with workouts then it will be very low carb just to avoid these complex situations.

Without knowing what you had for dinner and how much you bolused its difficult to say, but if you go low after a meal then its to much insulin. If you go high overnight then your basal is to low. The overnight line on your libre data should be as flat as you can get it.

I would probably put this down to a one off though and some more T1D experiance under the belt.

 

[The_Bowlii]

Your way more insulin sensitive after a high intense work out, up to around 2 hours. I really plan a meal and if it interferes with workouts then it will be very low carb just to avoid these complex situations.

Without knowing what you had for dinner and how much you bolused its difficult to say, but if you go low after a meal then its to much insulin. If you go high overnight then your basal is to low. The overnight line on your libre data should be as flat as you can get it.

I would probably put this down to a one off though and some more T1D experiance under the belt.

Thanks @pistolpete. Teriyaki salmon, Pak Choi and noodles. Calculated 70g carbs and took just 3 units of insulin. Also BG climbed to 11 post exercise (liver dump?) so thought I had loads of room. Obviously not. Normally flat through the night but it seems to be some sort of rebound post exercise, going low and then correcting mid-evening. It waits until I’m asleep and creeps up on me!

 

[pistolpete]

Sounds delicious! and looks like you did everything correctly but knowing what you know now would you of taken the 3 units? again its all down to experience.
Could be liver dump post exercise or could be your basal is not soaking it up like its suppose to, you say normally flat overnight if it does have a upward trend then it looks like your basal is to low. Liver dumps are usually short lived but depending how demanding the muscles are will pay a big part. Getting your correct basal dose takes a while and a lot of fine tuning.

 

[SimonP]

I wonder if you took too much insulin for the post-exercise insulin sensitivity part (what was your pre-injection/dinner BG reading? - if < say 6mmol/l I'd probably delay injecting until I've started eating, or have ice-cream to hand), but then the food absorption was taking place both during and after your body had finished replenishing glycogen stores which means you'd be back to needing normal insulin from that point on.

I originally wrote something to say that I don't get post-exercise insulin sensitivity very much these days unless it's been an all-day ride (and even then not much), however, as I always split my evening bolus dose I can't be quite sure that my gut feeling is completely correct. Certainly if I eat something smaller than a full meal I would need to inject the normal bolus for it (unless I'm low when I get home), but in that case I've not been out all day!

 

[The_Bowlii]

I wonder if you took too much insulin for the post-exercise insulin sensitivity part (what was your pre-injection/dinner BG reading? - if < say 6mmol/l I'd probably delay injecting until I've started eating, or have ice-cream to hand), but then the food absorption was taking place both during and after your body had finished replenishing glycogen stores which means you'd be back to needing normal insulin from that point on.

I originally wrote something to say that I don't get post-exercise insulin sensitivity very much these days unless it's been an all-day ride (and even then not much), however, as I always split my evening bolus dose I can't be quite sure that my gut feeling is completely correct. Certainly if I eat something smaller than a full meal I would need to inject the normal bolus for it (unless I'm low when I get home), but in that case I've not been out all day!

I was at 11 mmol/l before dinner with the “liver dump”, took just 3 units insulin for 70g carbs so thought it would be fine. Mostly low GI carbs so perhaps the insulin was in my system and working before the carbs had digested. I normally inject about 5 mins before eating so perhaps could have delayed until I started eating. Oh well - another day, another data point!

 

[SimonP]

Tricky one, I think I'd have done exactly what you did. As you say another data point.

 

[The_Bowlii]

Good experience this morning 🙂 Took less insulin (2 units for 80g carbs) including a banana before setting off. Rode for 2.5 hours with no extra food, just a bit of carb drink and levels all stable. Trouble now is my Libre stopped working in the cold! I’ll give it a couple of hours and change for a new one if it doesnt work - it’s due to be changed Tuesday anyway. Different day, different challenge 🙂

 

[helli]

Trouble now is my Libre stopped working in the cold!

If it is just the cold, it should spring back to life as it warms up.

 

[The_Bowlii]

If it is just the cold, it should spring back to life as it warms up.

Thanks @helli. It was almost time to change it so eventually did that as it didn’t work after another 3 hours. And I’ll be away with work this week so removing as many variables as I can!

 

[SimonP]

Out of interest what did it do? Just start reporting errors/no data? I've not had one stop due to the cold (yet!)

 

[The_Bowlii]

Out of interest what did it do? Just start reporting errors/no data? I've not had one stop due to the cold (yet!)

It just stopped working and never restarted. The app greyed out and I tried to reconnect / rescan over 3-4 hours but no joy. I was travelling with work from Monday morning, back late tonight by which time it would have been time to change the Libre. Rather than head off to The Big Smoke with no Libre and no idea where I was eating, the choice was made!

 

[The_Bowlii]

Been a couple of weeks since I’ve posted on here. Really getting there on the cycling and did 4 hour ride on Sunday. Food was breakfast of porridge and berries, bit of toast and just 2 units of insulin. Had a small snack after 90 mins and stopped after 2 hours for lunch. My BG started to fall so I acted too quickly and took a gel and bar. On top of this I added a bacon and egg roll and no insulin…30 mins later on the return ride, BG was heading high (over 14) so took single unit of insulin and all fine all the way home. Lesson learned.

I’m also playing squash 4-5 times a week so manage it with 20g carbs about 15 mins ahead of a match and top up with carb drink as required. In total, I consume 40-60g carbs over the 40 mins which seems to do the trick. Post match, I often have a short spike (liver dump?) but it settles quickly.

From a sense of absolute despondency just two months ago, I’m almost back to normal and making plans for next week, next month and next year. Thanks all for your help. Brilliant!

 

[SimonP]

Glad we could help, I'm really happy to hear how you're getting on 🙂

 

[The_Bowlii]

Glad we could help, I'm really happy to hear how you're getting on 🙂

Hi @SimonP - hope all well with you. I’ve not been in touch for a while but wanted to let you know the cycling (and squash) is going well. Did 75 miles today - it was a bit cold and I fell off on some sheet ice but otherwise all fine.

Couple of questions for you if you don’t mind…

1. During the ride, my levels peak quickly post breakfast and then seem to settle fine at about 7.5 mmol/l. As I don’t want to push them up when the insulin has worn off, I’m nervous about eating to keep up energy levels. Am I ok to keep fuelled (jelly babies, energy bars, carb drink) whilst pedalling or do I risk going high?
2. If I stop during a ride at a cafe, my levels drop quite quickly to about 4.5 mmol/l. I don’t panic (these days 🙂 ) and just have coffee and a snack with no insulin and set off again. My levels return to 7.5 mmol/l and it’s all fine. Any idea why levels drop when I stop? Also, do muscles need insulin or can they consume glucose as a fuel without it if I push hard enough?

Thanks for any insight!
Chris

 

[SimonP]

Hi @SimonP - hope all well with you. I’ve not been in touch for a while but wanted to let you know the cycling (and squash) is going well. Did 75 miles today - it was a bit cold and I fell off on some sheet ice but otherwise all fine.

Glad you're doing well, sorry to hear about the icy fall! I'm well though I must admit I've not been out all that much recently (lots of work and weather - so turbo it is, but even that has been fairly low priority.) I did get out for a Christmas day ride (wet!) but didn't try the festive 500 (I didn't fancy getting wet repeatedly!)

Couple of questions for you if you don’t mind…

1. During the ride, my levels peak quickly post breakfast and then seem to settle fine at about 7.5 mmol/l. As I don’t want to push them up when the insulin has worn off, I’m nervous about eating to keep up energy levels. Am I ok to keep fuelled (jelly babies, energy bars, carb drink) whilst pedalling or do I risk going high?
2. If I stop during a ride at a cafe, my levels drop quite quickly to about 4.5 mmol/l. I don’t panic (these days 🙂 ) and just have coffee and a snack with no insulin and set off again. My levels return to 7.5 mmol/l and it’s all fine. Any idea why levels drop when I stop? Also, do muscles need insulin or can they consume glucose as a fuel without it if I push hard enough?

Thanks for any insight!
Chris

Of course, not sure how much I can help mind you!

Those sound like really good readings, I still suffer from overshooting when I head out due to not wanting to take too much bolus for dawn phenomenon + breakfast - out of interest are you taking bolus for breakfast?

1. If you're stable at 7.5mmol/l then you probably don't need to eat anything - I assume your body must be doing a good job of fat metabolism and/or balancing your liver's glucose delivery with your basal insulin. No harm in trying and seeing what happens if you do have a few jelly babies - you will eventually burn it off and even if you don't it's not going kill you running a bit higher than ideal once in a while. I tend to find that I need to start eating after 1.5h to 2h or thereabouts, which I always assume is when my liver has decided it's going to stop producing glucose unless it really needs to. How long are you riding for with stable BG?

2. I don't get this effect at all. When I was riding lots over the summer/early autumn I'd just remain stable when I stopped, but now having not ridden all that much I find I actually get a slight rise when I stop (and I also now get a noticeable reduction in requirement for insulin post exercise and for the following ~48h, while over the summer nothing would change unless it was a very long ride).

I would guess your muscles are still hoovering up glucose and when you stop exercise your liver is no longer producing as much as the exercise-related stress hormones have gone away.

I have read that during and presumably immediately post-exercise your muscles do not require insulin to use glucose (https://diabetes.org/health-wellness/fitness/blood-glucose-and-exercise#:~:text=When your muscles contract during,insulin is available or not.) though I am not certain where that came from. One thing the muscles certainly do is to become much more sensitive so they are able to take in glucose much faster for a given level of insulin. I always have insulin on board in the form of some basal, I'd not want to experiment with having nothing on board as therein lies the path to DKA (perhaps it's possible to stave off DKA if you have no IoB by continual exercise, but it strikes me that this is probably unlikely and would be pretty hard to test safely!) Towards the end of a long ride having not injected bolus for ~10h I will continuously run low, so what little insulin is there is apparently being very effective.

If you're wondering about applying more power to burn more glucose, I think this holds true, however, there's also the annoying effect of higher power producing more exercise stress hormones which then encourage the liver to produce more glucose - I guess that once one is beyond a couple of hours (in my case) and my liver has decided it's less keen to provide glucose at the drop of a hat, this may be effective.

I've not really paid all that much attention I'm afraid, I am planning some data diving so will see if there's anything useful, I also plan to do some more literature searching to see if there's a relationship between the liver's production of glucose and how much glucagon glycogen (typo!) it has onboard - i.e. does it taper off based solely on glucagon glycogen (typo!) content? Probably quite a hard and niche experiment to perform, so I'm not holding my breath!

 

[The_Bowlii]

Glad you're doing well, sorry to hear about the icy fall! I'm well though I must admit I've not been out all that much recently (lots of work and weather - so turbo it is, but even that has been fairly low priority.) I did get out for a Christmas day ride (wet!) but didn't try the festive 500 (I didn't fancy getting wet repeatedly!)


Of course, not sure how much I can help mind you!

Those sound like really good readings, I still suffer from overshooting when I head out due to not wanting to take too much bolus for dawn phenomenon + breakfast - out of interest are you taking bolus for breakfast?

1. If you're stable at 7.5mmol/l then you probably don't need to eat anything - I assume your body must be doing a good job of fat metabolism and/or balancing your liver's glucose delivery with your basal insulin. No harm in trying and seeing what happens if you do have a few jelly babies - you will eventually burn it off and even if you don't it's not going kill you running a bit higher than ideal once in a while. I tend to find that I need to start eating after 1.5h to 2h or thereabouts, which I always assume is when my liver has decided it's going to stop producing glucose unless it really needs to. How long are you riding for with stable BG?

2. I don't get this effect at all. When I was riding lots over the summer/early autumn I'd just remain stable when I stopped, but now having not ridden all that much I find I actually get a slight rise when I stop (and I also now get a noticeable reduction in requirement for insulin post exercise and for the following ~48h, while over the summer nothing would change unless it was a very long ride).

I would guess your muscles are still hoovering up glucose and when you stop exercise your liver is no longer producing as much as the exercise-related stress hormones have gone away.

I have read that during and presumably immediately post-exercise your muscles do not require insulin to use glucose (https://diabetes.org/health-wellness/fitness/blood-glucose-and-exercise#:~:text=When your muscles contract during,insulin is available or not.) though I am not certain where that came from. One thing the muscles certainly do is to become much more sensitive so they are able to take in glucose much faster for a given level of insulin. I always have insulin on board in the form of some basal, I'd not want to experiment with having nothing on board as therein lies the path to DKA (perhaps it's possible to stave off DKA if you have no IoB by continual exercise, but it strikes me that this is probably unlikely and would be pretty hard to test safely!) Towards the end of a long ride having not injected bolus for ~10h I will continuously run low, so what little insulin is there is apparently being very effective.

If you're wondering about applying more power to burn more glucose, I think this holds true, however, there's also the annoying effect of higher power producing more exercise stress hormones which then encourage the liver to produce more glucose - I guess that once one is beyond a couple of hours (in my case) and my liver has decided it's less keen to provide glucose at the drop of a hat, this may be effective.

I've not really paid all that much attention I'm afraid, I am planning some data diving so will see if there's anything useful, I also plan to do some more literature searching to see if there's a relationship between the liver's production of glucose and how much glucagon it has onboard - i.e. does it taper off based solely on glucagon content? Probably quite a hard and niche experiment to perform, so I'm not holding my breath!

Morning @SimonP . Thanks as always for the great reply. Answering your questions (I've not yet worked out how to split the responses in the thread!):

Yes, I take bolus with breakfast. I have 14 units basal every morning no matter what and then tweak the bolus depending on what I am intending to do after breakfast. Typically, I have a breakfast of porridge, berries, seeds and a slice of toast which is about 70g carbs. I've tried everything between 2 and 8 units of bolus and found that I need 4 units if going cycling and 6 units if I'm having an office day on my backside. The only change to this is if I play squash first thing on a weekend when I do it with basal only, no bolus and fasted overnight. Amazingly, levels stay solid throughout following which I have my breakfast with reduced (4 units) basal.

On point 1, with breakfast and 4 units of insulin, I'll initially rise to about 10 mmol/l and then it will come down slowly and sit at around 7.5 for 2-3 hours. Once I stop, however, and as mentioned in point 2, that's when it falls very quickly so have to be careful to get some food in.

I did a hard turbo session last night as I was around 10mmol/l and hadn't injected for about 5 hours. My BG fell to <4 mmol/l so ate straight away and took bolus 15 minutes later. I was up and down like a yoyo all night plus my sensor kept dropping out and alarming so a bit on the tired side today! Every day is a new challenge... 🙂

Best wishes

Chris

 

[SimonP]

Hi Chris,

The sensor dropping in and out I've noticed recently - it seems to be unhappy with large rates of change (positive and negative) of BG, which is probably fair enough (but also something that does happen with sports), I also notice that it often comes back with a bit of an offset after one of these episodes, but tends to settle back down eventually (I don't need XDrip+'s calibration much these days, but it's nice to be able to keep an eye on it just in case a sensor goes TU.)

Sounds like the normal riding is working really well, I'm really pleased for you. It would be interesting to see if you start trending down on really long rides (but perhaps more an experiment for the summer, or indeed to be skipped completely!) I'm assuming you may still have some endogenous insulin production helping you along (and not helping post-ride).

The hard turbo session is an interesting one, you'd expect a rise in BG from a hard session (again driven by exercise induced stress hormones causing the liver to up its conversion of stored glycogen to glucose) and then probably a low afterwards. One of those things I guess! 🙂

As an aside I found in the autumn that I didn't need to reduce my basal as much in the morning for long days (I'm half tempted to leave it along completely for anything less than 100 miles, though it will probably all change again once I get out doing those sorts of distances again!) On the one hand if it's less stress (because I'm fitter and riding at a lower % of FTP (or whatever metric one choses)) that would mean less glucose production by the liver, which ought to mean I'd go lower during the ride rather than what I found which was that I didn't need to eat much. Alternatively, perhaps there's a change in muscle-insulin sensitivity. It could also be a change in how the liver delivers glucose - less but over a longer period (apparently there is some research pointing to this effect for habitual exercise.) More thought (and experimentation) required I think! 🙂

P.S. To split a reply (keeping the "Quoting blah" at the top), just press enter somewhere in the quote and it will split into two or as many as you want pieces.