Hypos during even very mild exercise

Hello All,

I've had a look around the forum but can't find anything specifically about what I am after. My son was diagnosed with T1D about 18 months ago, he is in his late teens. He manages his diabetes very, very well and I take my hat off to him (in range >95%) but one issue he does have is going low even during very mild exercise - eg a 20 minute walk to the post box and back will make his blood sugar plummet and he'll have to eat and eat to get it back up.

In the past he has been walking for a few hours and not gone so low so quickly so why this is happening so much now is a bit odd.

He current take 4.5 unit's of Basal (Tresiba) each night as well as a bolus for each meal. He snacks up to about 15g of carbs in between meals with no insulin which doesn't appear to raise his BS substantially.

Has anyone else had a similar experience and if so how do you handle it as he's finding it a bit of a pain and obviously as his mum it worries me.

Thank you

Hello all and thank you for your replies.

@becca59 I will look into a fasting basal test - isn't that the same as not eating over night though or am I misunderstanding what this test is/show? I assumed it was 'normal' for a T1D to be able to eat up to 15g carbs without insulin, how little I know !!

@ert I see you mention cutting back on your basal and short acting if exercising . Cutting back on basal isn't possible as he's not on a pump but he cuts back on bolus if doing proper exercise - eg walking for hours on end. In fact if he walks around all day eg a shopping trip/hiking he takes about 30% less basal otherwise it can get ugly. I'm just talking about walking up the (very flat) road and back to the post box or round the corner to college so pretty much an everyday amount of low level exercise - maybe he needs to cutback for this too as it is exercise?

@Fenn thank you, it's interesting that you get a similar effect. If we get to the bottom of it and come up with a good solution I'll let you know

Victoria B said:

Exercise can be a tricky one.I think his basal could do with being looked at if he can have snacks and not need a bolus.The bolus itself can be reduced at the meal prior to exercise.I’m on an insulin pump where you can reduce or increase the bolus by percentages but I’d talk to your diabetes specialist to see how much you should reduce it by especially with being on injections.95% in target that’s amazing!Hope you find a solution soon x

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Hi, thanks for your reply. He was told on diagnosis that he could eat up to 10g of carbs without insulin. It just so happens to be closer to 15g and once it was 25g after going for a bit of a walk.

I'd assumed all people with diabetes could do this to an extent.

I understand that the bolus can be reduced prior to exercise, but I'm talking about situations when the bolus has been 2-3 hours ago, his BS is about 5 point something, he walks for about 20 minutes and it drops to 4 so he needs to eat to get his BS up a bit

Circuspony said:

I have the same in that certain times of the day even a short walk can cause my BG to plummet. For me it's definitely a tail effect of novorapid because it doesn't happen if I eat lettuce leaves all day and just take my tresiba.

Initially it was thought my pancreas was dumping a bit of insulin but I'm 5 years post diagnosis now and it's still happening so with my own tests and exclusions I've worked out it's the novorapid. I'm fine in the morning but anytime after 4 pm is hard and it seems to be the cumulative effect of breakfast and lunch insulin with exercise. I've spoken to the consultant many times but they just repeat the NHS stuff back at me so I've given up trying to get help and just carry sugar!!

Btw I can also eat 10-15g without a bolus. I think those of us that are more sensitive to insulin can

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That is very, very interesting thank-you for your reply. Our son is also on Tresiba and Novorapid.

I had read that Novorapid stays in your system for 4-5 hours but that it's effect gradually tails off - maybe it doesn't tail off as much in some people, especially as you say if they are sensitive to insulin. I also think he is quite sensitive to exercise as if he's consistently very active he needs practically no bolus insulin.

I'm pleased you can still east 10-15g without insulin after 5 years as I was hoping this 'feature' would remain for our son as he is a bit of a snacker and being able to do this makes life so much easier

StewM said:

I experienced a similar issue with Tresiba when I was using it, and I found it was because I actually had my Tresiba dose a little on the high side (like less than 10% too high). It might be worth discussing with your Doctor if they believe it would be worth trialing a reduction in dose?

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Thank you , yes this is what he's currently doing