Average Blood Sugar vs Morning Blood Sugar before breakfast

[MarkH]

Hi All,

Diagnosed in Dec as T2, then T1, then T2 … Anyway …

Metformin, diet, exercise and my first thing morning before breakfast at 10am was 6.8-7.4 last week

The attached table equates average blood sugar to HbA1c. I don’t have a Libre, and generally test once a day, so I cant judge an average. Regardless it would have to be the same for 3 months to equate to a HbA1c accurately

I’m due another HbA1c in 2 months.

So my question is … what’s everyone’s experience with their relationship between Average daily blood sugar and before breakfast reading? Similar/higher/lower?

Thanks

Mark

 

[Windy]

Hi Mark,
do you do a fasting reading just after you've got out of bed, or always a 10am ish pre-breakfast one? I do a fasting one as soon as I get up, so I'm not sure how to interpret your breakfast one at all, as after you've exercised, your BG may have changed. I know that exercise can reduce your BG, but your liver will have put out some glucose to keep you ticking over when you exercise, to power your muscles, so I don't really know if the fasting one would have been higher or lower.

Is there a particular reason why you only do one reading a day? I appreciate it's not maybe the funnest activity, but I like to get the data so I can see how things are going with my BG, and amend my meals based on that.

Could you do a week of more intensive BG testing and see if you can work out what's going on with that? I'd be wary of trying to predict your HbA1c based on a single reading a day, as you don't know what your BG is doing the rest of the time.

Pre and post breakfast: I track my BG and average BG on a spreadsheet, my average fasting BG was 5.5 over the last 3 weeks, and the average of all the readings I took (fasting and pre and post meals) was 6mmol/L, though I'm on a low carb (max 20ish grams of carbs per meal), 1500 calorie diet, so unsure if this helps you or not. Based on 6mmol/L, looking on your chart, my HbA1c should have been 33mmol/mol, and I had the results for it yesterday and it was 42mmol/mol.

Sorry to hear that they can't decide what sort of diabetes you have. Must be quite frustrating.
Sarah

 

[MarkH]

Not really re question. But thanks. Def lots of interesting info re diet leading to getting your numbers down. Yeah diagnosis has been pain in the ass. They think I’m now type 2. Reading these forums, seems many people get reclassified on their journey.

Seriously impressed by your numbers. 800 cals over Xmas is an unbelievable achievement in itself. My numbers are stagnating a bit, I need to go hardcore on the diet, hence wondering what a HbA1c would equate to if my numbers remained as is. 6.8/7.4 in the am before breakfast

I need people with a CGM who can then state whether their first thing am after waking, before breakfast is generally higher/lower than their average daily on their CGM. Maybe most are higher/lower/similar and there’s some correlation

I’m not predicting now as it would only make sense if blood glucose remained the same for 3 months.

My train of thought was hypothetically if that were so and I had responses stating average was higher/lower/similar than am reading I could make an assumption on future HbA1c, although I realise other factors come into play (peoples spikes will differ due to diet/individual resistance etc). I guess I’ll see in a couple months

Cheers

Mark

 

[grovesy]

I use a Libre , I can see my level is lower before I get up to go to the bathroom in the morning. This morning mine was 6.4, on going back bed it was 8.7. For me the predicated HBA1C from my Libre is lower than my lab tests are.

 

[EmmaL76]

For me personally the hour after I get up will always be the highest reading of the day. I am very low carb though. So for me if I was to go on that one reading alone to try and gauge my hba1c I would say that my actual a1c would be lower. My predicted libre has always been lower than actual too grovesy… I put this down partly to compression lows during the night

I’ve also been through several changes in diagnosis mark, type 2, type 1, type 2 again now type unknown… type non of the above will do me

 

[Windy]

Mark, you can get a free trial Libra 2 from Abbot if you want to see what your BG is doing through the day. Lasts for 2 weeks apparently, though I've not tried myself. I think you need a compatible smart phone to read the sensor.
Best wishes, Sarah

 

[richardmillar11]

Mark my morning readings were similar to yours and my HBa1c fell to 55 from 115 in three months so you will def see an improvement. Hit he diet hard I started introducing carbs and some dark chocolate and my bedtime and morning readings crept up to the 9s so diet is vital if you want to get the morning readings low.

 

[grovesy]

For me personally the hour after I get up will always be the highest reading of the day. I am very low carb though. So for me if I was to go on that one reading alone to try and gauge my hba1c I would say that my actual a1c would be lower. My predicted libre has always been lower than actual too grovesy… I put this down partly to compression lows during the night

I’ve also been through several changes in diagnosis mark, type 2, type 1, type 2 again now tynknown… type non of the above will do me

I doubt mine is anything to with compression. I also find the same with the mySugr prediction too!

 

[rebrascora]

When you test on a morning can have a significant impact on the reading you get. If I test before I get out of bed, it would be 3-6mmols lower than just before I have breakfast an hour later if I didn't inject insulin to curb that Foot on the Floor liver dump of glucose, so that might be something you want to consider. It is normal for the liver to pump out glucose when we wake to give us energy for the day ahead. It is often referred to as Dawn Phenomenon or more colloquially here on the forum as Foot on the Floor. The readings you are seeing for your fasting test before breakfast may well be inflated by this factor, so you might want to experiment by testing before you get out of bed and see if you get lower readings then.

It is generally considered with Type 2 that waking readings are the last to come down into range, but if you are eating high carb foods through the day and your levels are spiking high and not coming down quickly enough, then guestimating your HbA1c from an average of your fasting HbA1c is probably not reliable. It could also lead you into a false sense of security meaning that you may perhaps not put as much effort into your dietary changes as you need to.
Using a structed testing strategy before and 2 hours after meals will give you much more useful data to help you lower HbA1c.

 

[Docb]

@MarkH. The question you raise is a good one. The answer is far from straightforward and the tables you have posted are just one answer. How good it is depends very much on how the data was derived and quite what is meant by "average" blood glucose.

If you look out my thread on stopping gliclazide, https://forum.diabetes.org.uk/boards/threads/stopping-gliclazide.98008/ , you will find a graph showing how my blood glucose varies during the day. There is a lot of data there but even so deciding what my "average" blood glucose was from all that data is not easy. Getting an average to relate to a HbA1c from a few finger pricks is down right impossible.

To my way of thinking it is a bit of a fools errand to look at finger prick readings and try and predict a HbA1c. What you can do is look at the data you are getting and ask whether they are different to what they were a month or two ago. Are they generally higher or lower? If you plot them out on a graph, can you see any trends? Have you made any changes and can you see a definite effect? If you want to see what I mean, then look in the stopping gliclazide thread where there is a graph which shows that my blood glucose levels quite clearly moved upwards after I stopped taking the gliclazide.

So my take is that the data you get from your meter gives a brilliant guide to where you are and where you are going but it does not pay to try and get too cute with interpretation. I think of it as a bit like adult Sudoku, with the added complication that there might not actually be a solution!

PS... I have a HbA1c due at the end of March. I will post a prediction of the result based on my data beforehand and see how close I get.