# Blood glucose levels before exercise (with insulin)



## soupdragon (Oct 21, 2021)

Hi 

My BG levels tend to drop very quickly during exercise. I usually try not to exercise (especially at the gym) until 4 hours after taking short acting insulin and swap between weights and aerobic exercise when I visit the gym (which generally stops me dropping low as long as I don't exercise for too long).

I'm hoping to return to the gym after an op but will be just doing fairly gentle aerobic exercise to start with, so will have to make sure that my levels are high enough before exercise. I usually aim to be above 10 and eat a banana before going to the gym. 

So ....I'm being nosy and wondered if anyone would be happy to tell me what levels you might aim for before exercise?

My DSN told me that I might need to aim to be a bit higher when exercising. I have to admit that, although I'm better than I was about this, I still don't really like being high for long.

It would be really helpful to know how others manage their levels before exercise.


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## helli (Oct 21, 2021)

As you have noticed, it depends what type of exercise I am doing. 
However, as I have an insulin pump (exercise was the justification for the pump), I use my basal setting to help me manage my blood sugar levels during exercise. For example, 
- Climbing always pushes my levels up (probably something to do with the shortish climbs with breaks and the adrenaline causing my liver to dump glucose) so I increase my basal. Prior to pumping, I would aim for a low level of around 4mmol/l before hitting the walls. 
- Cycling and running causes my levels to drop so I suspend my basal for an hour before I start. Prior to having a pump, I would aim for a level around 7 or 8 with no insulin on board. I would not eat beforehand but I would add a few drops of squash to my water bottle so that I would be taking on sugar throughout my workout to maintain levels rather than assuming they were going to drop.

Generally, I find I have most energy when my levels are around 5 or 6. Anything higher than 8 and I feel very sluggish so I am unable to exercise.


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## soupdragon (Oct 21, 2021)

helli said:


> As you have noticed, it depends what type of exercise I am doing.
> However, as I have an insulin pump (exercise was the justification for the pump), I use my basal setting to help me manage my blood sugar levels during exercise. For example,
> - Climbing always pushes my levels up (probably something to do with the shortish climbs with breaks and the adrenaline causing my liver to dump glucose) so I increase my basal. Prior to pumping, I would aim for a low level of around 4mmol/l before hitting the walls.
> - Cycling and running causes my levels to drop so I suspend my basal for an hour before I start. Prior to having a pump, I would aim for a level around 7 or 8 with no insulin on board. I would not eat beforehand but I would add a few drops of squash to my water bottle so that I would be taking on sugar throughout my workout to maintain levels rather than assuming they were going to drop.
> ...


Thanks for that @helli. That is very interesting. I might try some juice in the water bottle and see how I get on with that.
A pump was mentioned at my last clinic appointment due to the problems that I'm having with exercise. The next appointment is in a couple of months so I'm hoping to discuss it further then.


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## Inka (Oct 21, 2021)

It depends on the exercise and the situation really. When I used to swim regularly, I aimed for around 9 before getting in the pool. This worked pretty well. I also cut my bolus for the preceding meal. The combination of those two things allowed me to swim without topping up with Dextro usually.

For walking, and aerobic exercise, I generally aim for somewhere in the 6s or 7s then top up with Dextro or Coke as needed.

Sadly, only experimentation will give you the answer. I was also told to never exercise if I was above 12.5 (I think - might have been 12) as that wasn’t a good idea.


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## rebrascora (Oct 21, 2021)

I find once my levels get above 8 I start to feel like I have lead weights around my wrists and ankles and everything is much harder work. I don't find that enjoyable, so I tend to try to keep below 8 and then top up as needed as I go along. Libre is fantastic for keeping track of how things are going especially with the direction of travel arrow so I can see when I need to top up carbs.


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## soupdragon (Oct 21, 2021)

Inka said:


> It depends on the exercise and the situation really. When I used to swim regularly, I aimed for around 9 before getting in the pool. This worked pretty well. I also cut my bolus for the preceding meal. The combination of those two things allowed me to swim without topping up with Dextro usually.
> 
> For walking, and aerobic exercise, I generally aim for somewhere in the 6s or 7s then top up with Dextro or Coke as needed.
> 
> Sadly, only experimentation will give you the answer. I was also told to never exercise if I was above 12.5 (I think - might have been 12) as that wasn’t a good idea.


Thanks @Inka. I was also remembering the advice about not exercising above 12 or 12.5 (I can't remember which one it was either!) and don't generally feel keen to exercise at those levels.
I'll keep experimenting ....


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## soupdragon (Oct 21, 2021)

rebrascora said:


> I find once my levels get above 8 I start to feel like I have lead weights around my wrists and ankles and everything is much harder work. I don't find that enjoyable, so I tend to try to keep below 8 and then top up as needed as I go along. Libre is fantastic for keeping track of how things are going especially with the direction of travel arrow so I can see when I need to top up carbs.


Thanks @rebrascora. I'm also not keen to exercise when the levels are too high, so don't really want to push them much over 10 before exercise.
I find Libre brilliant when walking and gardening but it sometimes struggles when I'm exercising more vigorously. Unfortunately I get the scan again in 10 minutes message when the glucose is dropping fast, just when I really need to know what it is!


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## rebrascora (Oct 22, 2021)

soupdragon said:


> Thanks @rebrascora. I'm also not keen to exercise when the levels are too high, so don't really want to push them much over 10 before exercise.
> I find Libre brilliant when walking and gardening but it sometimes struggles when I'm exercising more vigorously. Unfortunately I get the scan again in 10 minutes message when the glucose is dropping fast, just when I really need to know what it is!


I still have the original Libre which I think may cope better with rapidly changing levels than the Libre 2 does. The only time I have problems with it is if I am out in the cold air with bare arms and it gets cold and shuts down. Had problems a few times last winter, but then I have problems with my glucose meter in the cold as well. 5 mins down my bra usually sorts that out thankfully but can't do that with a sensor on the outside of my arm!!


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## soupdragon (Oct 22, 2021)

rebrascora said:


> I still have the original Libre which I think may cope better with rapidly changing levels than the Libre 2 does. The only time I have problems with it is if I am out in the cold air with bare arms and it gets cold and shuts down. Had problems a few times last winter, but then I have problems with my glucose meter in the cold as well. 5 mins down my bra usually sorts that out thankfully but can't do that with a sensor on the outside of my arm!!


I think you may well be right over Libre 2. The new algorithm means the readings are much closer to BG than Libre 1 for me most of the time but I can easily confuse it with vigorous exercise or just getting up from the sofa!


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## Deleted member 33898 (Nov 11, 2021)

@helli I've seen you mention about drinking water with squash to maintain levels during exercise. Just wondering what squash are you using, any I've come across have a very tiny amount of sugar. I like this idea  of maintaing levels rather then going up and down abruptly which is what happens to me as I take a few jellies mid way or at the end of a run.


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## trophywench (Nov 11, 2021)

It's a flippin nuisance to Type 1s now they've almost universally cut down the amount of sugar in drinks including flippin Lucozade and Ribena ........ I do not actually LIKE the taste of coke thanks !   Why expect me to drink nasty stuff when I'm hypo FFS?


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## helli (Nov 11, 2021)

jazzchicken said:


> @helli I've seen you mention about drinking water with squash to maintain levels during exercise. Just wondering what squash are you using, any I've come across have a very tiny amount of sugar. I like this idea  of maintaing levels rather then going up and down abruptly which is what happens to me as I take a few jellies mid way or at the end of a run.


I carry one of those small Robinson's Squash'd in my gym bag fro convenience. 
I have never considered how much sugar is in it, I think of how many drops I need in my water bottle to maintain my levels,


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## Deleted member 33898 (Nov 11, 2021)

@helli ah yes they have nearly no sugar in them. I was just wondering because I drink squash at dinner time. I guess it depends on person then. I'll need something bit more substantial


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## helli (Nov 11, 2021)

jazzchicken said:


> @helli ah yes they have nearly no sugar in them. I was just wondering because I drink squash at dinner time. I guess it depends on person then. I'll need something bit more substantial


Some people use dilute fruit juice.


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