Introduction and Question

1) you could try eating with your exercise bolus to avoid the hypo from the bolus. You could try jogging more gently - basically the exercise spikes are associated with release of adrenaline caused by intense exercise like sprinting, the adrenaline is counter regulatory to insulin so causes a spike.

2) have you done any actual blood tests to verify what the libre is telling you about nocturnal hypos is actually correct? There's a thing called compression lows that CGMs suffer from - this is when you lie on the sensor it causes it to show a lower reading than you actually are. It's a good idea to check what the libre is telling you with a finger stick. If you're deciding whether or not to adjust your basal dosage it would seem sensible to do a night basal test.

Yes, nocturnal hypos are to be avoided. Especially if they aren't waking you up.

Welcome @Mirabellae to the Forum .

Hi @Mirabellae,

Exercise can play havoc with blood sugar levels, in a number of different, and sometimes unexpected ways. In relation to your runs, as @catapillar says, if you're running quite intensely, this can cause blood sugar spikes. If you're just jogging, and not doing an all out sprint, then I suspect the reason you're going high is because there's not enough insulin in your system during the exercise - are you running before breakfast, and before you've had any insulin at all?

When you started taking 2 units before your run, did you eat anything too? If not, this will explain why you're going low to the end of the run.

You just need to find the right balance of carbs and insulin before exercise, and this might take a little experimentation. You do need some (but only a very little) insulin circulating while you're exercising, so the body can use glucose - if there's not enough, you'll go high; but having even that little amount of insulin presents a risk of lows - so ideally, you'd have a small pre-workout snack/shake (with some carbs) to prevent those lows. Are you carb counting? - if so, what is your ratio of insulin to carbs?

As you have the Libre, it should be quite easy to monitor your sugars during your run (and of course, always keep a fast acting source of glucose with you).

You said you're trying to gain weight - just remember that running will burn extra calories, and is not going to help build muscle, so won't really help with your weight gain goal; so if you're running, you'll have to make sure you account for those lost calories by eating more.

In relation to night time hypos, a little extra care may need to be taken to avoid these, especially if you exercise - exercise can lead to unexpected lows, at unpredictable times. What are your sugar levels before bed?

That's my pleasure @Mirabellae,

Okay, if you're taking insulin, with no carbs at all, and then exercising, that's why you're going low during the run!- but as I said, you do need a very little insulin in your system while exercising. The reason I ask whether you carb count, is to get an idea of your normal insulin/carb ratio - to see how this could be adjusted for exercise. How do you judge how much insulin to take with a given meal? Do you work on the basis of a carb/insulin ratio?

Perhaps it might be worth starting with 1 unit of insulin before the run, and having a very small source of carbs at the same time - many people don't like eating before exercise, but you could always have say 100ml pure orange juice (that's just 10g carb) - then keep checking your sugars throughout the run, with your Libre.



Running will definitely improve your overall fitness - but it won't help you gain weight, if that's your specific goal. Ideally, you'd do some weight-bearing exercise, which will help build weight in the form of muscle - but there's no harm in the running, provide you can eat the extra calories to cover it!

Your sugars are going way to low at night - do the hypos actually wake you up? You should never see "LO" on your glucose monitor! When did these night time hypos start - was it at the same time you started running?

Mirabellae said:

Hello @Odin004
First of all thank you for your detailed reply

As for your questions;
I usually dont eat anything before running due to feeling very sick during the run the few times i tried. I do take the 4 units of tresiba (split in 2 and 2) before the run.

No i stopped carb counting quiet a few years ago.. Is it worth starting again ?

Is running only good for burning calories and does not help me improve my overall fitness ?

My sugar levels usually vary between 5-8 before going to bed.
And if i wake up during the night i am between LO (thats what the meter shows) and 3.6

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Definitely start carb counting again - it's crucial for good control. It might also give you an idea on where to start to solve your hypos.

To my mind, nighttime hypos are potentially more dangerous because you might not be aware of them and might not wake up when you're having one.

Mirabellae said:

But are they in any way more dangerous than hypos during the day ?

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Well, yes. If nocturnal hypos aren't waking you up, you cant treat them. If you don't treat them there is a risk that you just... won't wake up. There's a thing called dead in bed syndrome which is applied to type 1 diabetics found dead in bed, it's uncertain what causes it but the theory is its nocturnal hypos. Severe hypos can kill you, either the low blood sugar causes such a shock to the system that it causes a heart attack or the low blood sugar causes a loss of cognitive function that your brain isn't capable of basic things like remembering to breathe. Having woken up (or rather roused from unconsciousness) with hypoglycaemic hemipelgia because my brain was so starved of glucose it couldn't work out how to make my right side move its not an enormous stretch to see that it may not work to remember to do breathing.

This is why nocturnal hypos should be avoided.

If libre has suggested nocturnal hypos, you should be doing some proper overnight basal testing (with finger prick tests) to find out what's going on and consider basal dose adjustments.

If you aren't carb counting, you may need to consider if dinner time bolus is contributing to night time hypos. How do you decide what to bolus if not by carb counting? Are you on fixed doses?

What are your hypos during the day like? Do you get good hypos symptoms when you're awake?

@Mirabellae - in that case, it sounds like your night time lows are likely to be related to your exercise earlier in the day. I would suggest:

- test regularly with your Libre during your run;

- keep a fast acting source of glucose with you during your run, just in case;

- when you go to bed, make sure any meal-time insulin is out of your system;

- do finger prick testing during the night to re-confirm your Libre readings;

- go to bed with slightly higher sugars (I'd say 5 is too low - around 8 is probably better).

You could always consider getting CGM - I use the Dexcom G5; it's a bit more expensive than the Libre - but it has a serious advantage - you can set an alarm to sound when your sugars reach a certain level; in theory, this has the potential to eliminate hypos, including those at night (as the alarm will wake you up in advance); you can also set an alarm to go off if your sugars are falling at a certain rate.

@Mirabellae sorry, wasn't intending to be scary. Dead in bed syndrome is super super rare, but it is a thing. And that's why avoiding nocturnal hypos is a priority in diabetic management.

The impact of exercise can be lows hours after, so you might need to think about reducing your post exercise meal bolus to try and stave that off.

I'm not sure how flexible Tresiba is, but it might be your basal can be reduced for run days.