Understanding Blood Sugar levels

[Davidden]

I was diagnosed Type 2 about 15 years ago - not sure exactly how long as I was on "diet and exercise" for about 12 years and managing to control my blood sugar (between 7 and 9) without too much effort. 2019 I needed a biopsy (on what turned out to be bone cancer) but my sugar levels were too high so they started me on insulin. I managed to get my levels down to a level they felt acceptable, and eventually had surgery in 2021 - it didn't take 2 years to get the levels down, but due to Covid pandemic it was difficult to get treatment, and by then the tumour weighed 5.2 kgs! This was all done in Peru where I was stuck during the Covid shutdown.
I came back to the UK in mid-2021 and had a diabetic review. I was told that levels between 13 and 18 were "acceptable", but I should aim lower. I eat fairly low carb, no sugar (using Stevia crystals - from Bolivia - in coffee), and do limited exercise (other issues like arthritis as well as now missing a shoulderblade), but feel fit and well - my only "worry" is my sugar levels!! I test 3 times a day - morning first thing (fasting), pre-evening meal, and before bed, My current target - from my last diabetic review (have a follow-up in 4 weeks) is "single figures", and have achieved that 3 times since March! My 90 day average is 12.9, brought about because my pre-dinner levels are all over the place - but sometimes I can identify the reason, like having a baguette for lunch, or (like yesterday) having chips, both which caused spikes of over 17!
Sorry for the long-winded preamble, but every Thursday I go to a Lifestyle Hub exercise clinic, which is aimed at diabetic and cancer survivors - age range from (guessing) 50 to me (70) - and it is a pretty good workout. We do circuit exercises, stretching exercises, and walking in a circle, and the "coach" says the intention is to make us sweat, and get a little out of breath (he does keep a good check on us all). Apart from the high carb lunch causing spikes, it appears that I get spikes after most of these sessions - today was 17.8, 30 minutes after the session, which was one of my highest pre-dinner readings. Is this normal? I am guessing that my body (liver??) feels I need an energy boost after the exercise so boosts the glucose production - but just wondered if anyone else had a take on this.

 

[KennyA]

Strenuous exercise goes along with raised blood glucose levels for me, while the exercise lasts. The diference seems to be adrenaline - playing football will see elevated levels, heavy digging won't. I suspect my liver is responding correctly to what my system needs at the time. Stop the exercise, levels quickly subside.

Incidentally, I'm not sure your current testing regime will give you much useful information. There's no ability to make "baseline and impact" comparisons from the information you're getting.

 

[EllieM]

Hi @Davidden this is certainly normal for me (T1 on insulin). If I go to the gym I usually need to take some insulin for it. I reckon the health gains of the exercise make it worth it but of course I have the option to inject short acting insulin before, during or after the session.

Your signature says you are on toujeo which is a long acting insulin so I think this is unlikely to be an option for you. (Interestingly lots of exercise makes my need for long acting insulin go down).

 

[Davidden]

Strenuous exercise goes along with raised blood glucose levels for me, while the exercise lasts. The diference seems to be adrenaline - playing football will see elevated levels, heavy digging won't. I suspect my liver is responding correctly to what my system needs at the time. Stop the exercise, levels quickly subside.

Incidentally, I'm not sure your current testing regime will give you much useful information. There's no ability to make "baseline and impact" comparisons from the information you're getting.

After a review in March I was told to test 4 times a day - fasting, before lunch, before dinner and bedtime, but in May they told me to reduce to 3 times a day, which I have done since then.

 

[KennyA]

After a review in March I was told to test 4 times a day - fasting, before lunch, before dinner and bedtime, but in May they told me to reduce to 3 times a day, which I have done since then.

Was there a particular reason for giving you those times to test?

Testing before meals gives you a baseline but tells you nothing about the impact of the meal on your blood glucose. The morning test I almost never do (once a year?) these days, and I've never tested when going to bed.

 

[Davidden]

Was there a particular reason for giving you those times to test?

Testing before meals gives you a baseline but tells you nothing about the impact of the meal on your blood glucose. The morning test I almost never do (once a year?) these days, and I've never tested when going to bed.

No reasons given - I just do what I am told. No-one has ever suggested before and after meals (haven't got enough fingers to prick!), and have not been told not to do first thing (which also tends to be before breakfast), nor last thing at night (about 3 hours after food). I clearly have no idea what I am doing, but would have thought that bedtime, and then first thing in the morning (about 7-8 hours later) would give some useful data??

 

[KennyA]

No reasons given - I just do what I am told. No-one has ever suggested before and after meals (haven't got enough fingers to prick!), and have not been told not to do first thing (which also tends to be before breakfast), nor last thing at night (about 3 hours after food). I clearly have no idea what I am doing, but would have thought that bedtime, and then first thing in the morning (about 7-8 hours later) would give some useful data??

For me, because I severely limit my carb intake, BG testing is about assessing the impact of the food we eat on our blood glucose, and then eliminating the (carbohydrate) foods that cause unacceptable rises. The logic behind this is that by the +2 hr point after eating, your system should have returned your blood glucose levels back to where they were prior to eating - or close enough. People are usually advised that what is wanted is no result of more than 2mmo/l between the two readings, and the second reading should not be above 7.8mmol/l.

Naturally, within the two hour period, blood glucose levels will have risen much higher but will have been brought down by the insulin responses. In one sense, this testing system is checking on how efficiently your insulin is working currently. If it can't handle the level of carb in what you ate, the way to help your system is to reduce the amount of carb you take in.

Morning readings are often affected by the liver dumping glucose (that it has manufactured) to give us a boost - my morning readings were often the highest of the day and were the last to reduce. Livers seem to be slow learners.

I'm struggling to see what a bedtime reading would tell me - yes, you get a value, but no information about why you got that value. I guess it's simply monitoring where you are for your insulin. Maybe someone else can think of another benefit. I've never done one unless a +2 hr after food happned to coincide with going to bed.

 

[becca59]

I suspect the testing recommended is in connection to the Toujeo and nothing to do with food being consumed. The Dr will want an idea of ongoing levels whilst taking this. The night time reading is important whilst on insulin. I know it’s only a basal but it is still important to be aware before sleep if those numbers are starting to creep too low.

 

[Davidden]

I suspect the testing recommended is in connection to the Toujeo and nothing to do with food being consumed. The Dr will want an idea of ongoing levels whilst taking this. The night time reading is important whilst on insulin. I know it’s only a basal but it is still important to be aware before sleep if those numbers are starting to creep too low.

Since diagnosis I have never had a "Low" - my lowest ever was 5.8 while in hospital (food was terrible so I was eating very little!). I take my insulin at 20.00 so that is about an hour after dinner, and 3-4 hours before bed. As it is slow release I have no idea what it really does! I do know that some days the "bump" (injection site) goes down in an hour or so, but it has remained raised for a couple of days on occasion! My last review was a strange one as I was seeing the nurse about another issue (she decided to combine the two) related to my shoulder (or lack of), and she had another "expert" with her, so I was not fully concentrating on either who were both questioning me.

 

[Angelofthemarches]

I would be interested also in your daily food intake - think you said it was generally 'low carb'. I'm guessing it would be helpful to measure blood sugar before and after your main meals (the 'two hour' measurement) and to log your carbohydrate intake for a few days. I wear the Abbott freestyle libre (T2 non insulin dependent) for a few weeks a year - it was an invaluable guide as to which foods spiked me. I logged my carbohydrate intake for at least a year and it proved really useful. I was 66 on diagnosis and have averaged 40 since diagnosis.

 

[becca59]

@Davidden a slow release basal like Toujeo hangs around in the system for 36 hours so. So each dose overlaps and just keeps the system ticking over. It looks after the normal glucose rises that everyone gets throughout the 24 hours but does not deal with food eaten. That is why type 1s take a second bolus insulin specifically to cover food.