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Momentum NHS VLCD / low MMOL on Libre2 when sleeping

M

Mo1977

Member
Messages
5
Type of diabetes
Type 2
Treatment type
Tablets (oral)
Hi all, I'm on day 8 into the NHS momentum very low calorie diet (800kcals a day).

As part of the program you have to monitor your blood glucose and they provide a finger pick device.

I was given a free trial of a Libre2 which I've used for 2 days.

The diet is going well (13lbs down) but I'm a bit worried about reading the reports from the libre2.

It shows a couple of times during the night my MMOL is going down to 3 for short periods before bouncing back to 4-5.

Can anyone suggest why it is doing this?

My plan tonight is to set an alarm if it goes to 3 then finger pick test myself incase the Libre2 isn't being accurate.

Any other suggestions/advice?
 
If your Libre graphs are showing a sudden dip and rise soon afterwards, this is a "compression low". Your BG is not falling, you are applying pressure to the sensor which blocks the filament from interstitial fluid (the stuff the sensor "reads" to calculate your BG) which results in a false reading. The reason this is most common at night it that you lie on your sensor.
CGMs like Libre are great but only if you understand the limitations like this.
 
I'll give it a go tonight lying on my left, what you say makes sense thankyou
 
I agree with @In Response those lows you are seeing are very likely compression lows. If you find the same pattern of lows this evening, think about positioning your sensor slightly differently Next time. I rarely get compression lows. I attach my sensor so that it is harder for me to squish it when I’m asleep.
These sensors are not 100% accurate, especially when your readings are either side of the normal range for blood sugar. They can be slightly off, for instance a 3 mmol/L reading maybe more like 4 mmol/Ls. I always finger prick to confirm a low. Blood is more accurate than the interstitial fluid the sensor measures. Plus, your sensor has a 15 minutes delay, due to the slower release of blood into the interstitial fluid. So the reading your Libre sensor throws out is 15 minutes behind your blood reading. Your blood reading is a real-time measurement and the one you should take notice of.
All measuring devices have an allowable degree of error. With blood monitors it is a 15% +/- allowable error from a comparable lab reading.

I have my sensor set at 4.5 - 7.5. The 4.5 is set because I am prone to night time lows, and they tend to happen around 3am. Just note that for someone who is NOT Type 1 diabetic, it is common for blood sugars to dip under 4 at night, for diabetics and none diabetics alike. A dip of around 3.5 is nothing to panic about. Your liver will very likely correct this low with a dump. You will see the low around 3.5 then a rise, maybe to 6. This will be your liver correcting the fall in blood sugar. Your body’s blood sugar needs are not as great during the night, so your blood sugars, if running at an healthy level will be naturally lower.

Now having said all that, you cross check your lows and you find you are actually running low, then adjustments to your diet or exercise regime will likely fix those night time dips if they are falling to around 3 mmol/ls.

I suspect with the increasing use of these CGM devices, we will see the ups and downs of our blood patterns, these patterns will demonstrate that our blood sugars are never constant but are in continous flux.
 
@Mo1977 - While the patterns you are seeing do look like they could be compression lows, they could also be real. The best approach is to verify against a glucometer test.

Your profile says you are on oral treatment for your diabetes. What's your current treatment? I found that I had to discontinue my Gliclazide and Dapagliglozin very early after switching to a low-carb diet as both of these had the potential to cause hypos and were frequently pushing me into 3s. I wasn't necessarily experiencing any other hypo symptoms but haven't seen such low numbers since these mediations were stopped.
 
Thanks all for your very helpful replies.

I started 8 days ago the NHS momentum very low calorie diet - 800kcals per day so I'm not taking any medication at this time.

I signed up for the libre2 free trial and received the device 2 days ago so only have those results to compare with. I've been going to vent a finger pick glucose tester.
 
Mo1977 said:
Thanks all for your very helpful replies.

I started 8 days ago the NHS momentum very low calorie diet - 800kcals per day so I'm not taking any medication at this time.

I signed up for the libre2 free trial and received the device 2 days ago so only have those results to compare with. I've been going to vent a finger pick glucose tester.
Click to expand...
Your graphs look very familiar.
An almost vertical drop is very likely to be a pressure low.
However you would expect the reading to bounce back up again as soon as you moved and released the pressure.

With longer term lows, I have seen those with sensors which were "low readers" so I would check your sensor against a finger prick when it shows you going low, and also generally during the day.

I use my phone to monitor my Libre 2 using LibreLink and my low glucose alarm is set to 3.3 mmol/L (which is as low as it can go) because as a T2 on pills only I have never knowingly experienced a true hypo, and when I go really low my liver seems to dump to bring me back up.
The alarm is set as low as possible to counter the false low readings waking me up in the middle of the night.

As always, your mileage may vary, so please go carefully.
 
@LittleGreyCat i understand why you have no need for the low alarms. I thought it was possible to turn them off rather than turning them down. Forgive me if I am wrong as it is some time since I used Libre.
 
In Response said:
@LittleGreyCat i understand why you have no need for the low alarms. I thought it was possible to turn them off rather than turning them down. Forgive me if I am wrong as it is some time since I used Libre.
Click to expand...
You can turn them off, but I prefer to set them as low as possible just in case.
If they get to be a real problem then I turn them off.
 
What medications are you on?
With certain of the "flozins" it's not recommended to suddenly go low carb, or very low calorie as the dose is based on weight and insulin levels and if either drop too quickly there's a small risk of dka. You'd have to reduce carbs/calorie slowly over several weeks instead.
It's in the small print on the info paper with the meds.
Your doctor will need to adjust your meds as you loose weight
 
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