What's happening to my blood glucose? Is it exercise?

[Keith Saunders]

Morning all. Hoping someone may be able to help me understand what is going on.

I'm recently diagnosed (Nov'23 - HbA2c of 55). Immediately cut carbs and started exercising. First met my diabetes nurse 11 Dec and managed to blag a glucose monitor from her. Testing before Christmas was really good (or so I thought) averaging out in the first two weeks at 6.2mmol.

Went away for Christmas so didn't measure for the week. Knew I wasn't going to be good and had talked that through with the nurse. Anyway back on it this week. Measure before and after dinner Monday evening - 5.5 - 8.1 (only my second recorded spike, but still below 8.5). Measured around dinner yesterday as well (almost exactly same meal) - 5.2-7.1 (no spike, so that's good). Got up this morning, went out for a run. Once I was back and sorted sat at my desk I did a pre-breakfast test - 8.1. Why is this suddenly so high (for me)? Never had such a high reading on a morning, though not sure I have tested after a run before (though it was over an hour after I'd got back). Had porridge and blueberries to eat, and my glucose has risen to 8.3 two hours after.

Really thought I was doing well but my overall average is now running at 6.7 (a full .5 over pre-christmas) and for this week only an average of 7.1. Appreciate that my readings are still relatively low, but I want to do more, if I can, to get them lower and keep them that way.

Any advice at all is appreciated, especially the question of - would running raise my Glucose levels?

 

[jaywak]

Exercise can make you spike it's like your brain telling your liver come on I need some glucose to get me through this a bit like the much talked about on the forum dawn phenomenon , porridge and blueberries is quite a high carb meal so I would say not that unusual to go a little high afterwards .

 

[Deleted member 527103]

In the morning, our "helpful" livers dump glucose to give us energy to start the day. This is called Dawn Phenomenon. It happens to most people regradless whether they have diabetes or not. We spot it because our bodies struggle to produce or use the insulin to convert this glucose dump to energy.
Our liver will continue to dump glucose until we eat as it thinks we are starving and it is trying to help out. By going for a run before breakfast, you are unintentionally sending signals to your liver that it needs to dump more glucose and your BG rises. Eating a small amount ( half a tub o yoghurt or a handful of nuts, for example) will shut down that signal.

However, exercise can raise BG too. But this depends on a number of things such as type of exercise, your fitness at that exercise, how much stress you place on your body during that exercise, how long your exercise it and possibly more. Typically, cardio will reduce BG and resistance training will increase it. As with most things diabetes related, it's not quite as simple as that. Take me and my cycling as an example. I am reasonably fit -I will exercise enough to raise my heart rate 4 or 5 days a week with a combination of walking uphill with the weekly shop, spin classes, outdoor cycling, climbing and general gym workout.
- If I pootle along the tow path on my bike, chatting to my friends, my BG stays reasonably steady
- if I go for a longish spring along country roads, my BG falls
- if I push myself up a steep hill, against the wind and rain, my BG will rise.

Basically, it is worth experimenting to find what works best for you.

 

[KennyA]

Hi and welcome. I don't think it's the running (although exercise does raise some people's BG). There might be a "dawn phenomenon component - where our livers add glucose to the bloodstream. They do this all the time but for many people it's very noticeable in the mornings.

I think it's the porridge and blueberries. Lorts of carb and fructose in that, and I'd expect to see a substantial rise and fairly slow decline in BG levels. Your blood glucose will have been much higher in the period between the first and second tests - the peak is often somewhere between +20 and +60 minutes. You are not testing to see "how high you go" - you're testing to see how well your system dealt with the carb load you placed on it - really "how quickly I came down".

One word of advice - don't worry too much about "averages" from fingerprick readings. These are snapshots only, and you have no data from when you don't test. So you'll get an average test reading, but it may tell you nothing about what your overall BG position is.

 

[Deleted member 527103]

@KennyA why would you think it was the porridge and blueberries when the OP mentioned they did a pre-breakfast (post-run) test which was 8.1 and 2 hours after the porridge it had only risen to 8.3 (which given the accuracy tolerance of a meter, is pretty much the same thing)?

 

[oldnevada]

My GP told me the same, he said, 'that's your fuel' He sounded almost impatient. I was expecting my BG to be lower after a 10km run routine. I was taking the nasty Glyburide at the time. I used to get tons of hypos.

 

[jaywak]

Without the high carb breakfast you may have even seen a drop in your bg an hour later . those figures are good so I wouldn't wind yourself up about it .

 

[JoKalsbeek]

My GP told me the same, he said, 'that's your fuel' He sounded almost impatient. I was expecting my BG to be lower after a 10km run routine. I was taking the nasty Glyburide at the time. I used to get tons of hypos.

Lovely, when they get impatient when you have an honest, logical question. But yeah, my vote goes to a combination of dawn phenomenon and an exercise dump. Your liver was being helpful. It'll dump to get you to the end of your 10k run, which you started on an empty stomach, so it was a bit of a double whammy. The run did cause the porridge with berries not to spike you overmuch though. If you'd not had the run, i do think it would've been decidedly higher. That's a good thing. And hey, whatever your liver dumps into your blood stream to be burnt off, is no longer stored in your liver. So you're all good.

 

[KennyA]

@KennyA why would you think it was the porridge and blueberries when the OP mentioned they did a pre-breakfast (post-run) test which was 8.1 and 2 hours after the porridge it had only risen to 8.3 (which given the accuracy tolerance of a meter, is pretty much the same thing)?

Hi

The question being asked is what caused the 8.3 and by extension what would have prevented it. As you'll be well aware, the main rise in blood glucose will occurabout 30 minutes after eating the porridge and (ideally) be over before the two hour mark. So it's almost certain that the OP's BG had risen quite a bit more in the two hours after eating than from 8.1 to 8.3.

I know from my own experience and CGM data that from a low five start I'll hit mid nines after about 30 minutes after only a small latte. That's gone after an hour.

So what would have happened if the OP hadn't eaten the porridge and blueberries? I'm suggesting that the reading would have been lower (how much lower would be, without any data, a guess) than 8.3, and that the main driver was the porridge etc.

 

[Birgitte]

Exercise can make you spike it's like your brain telling your liver come on I need some glucose to get me through this a bit like the much talked about on the forum dawn phenomenon , porridge and blueberries is quite a high carb meal so I would say not that unusual to go a little high afterwards .

My doctor has cautioned me against porridge for breakfast. He talked about glycemic load as well as glycemic index. Basically porridge has a high glycemic load. He said you could slow things down my adding cream and nuts.