Somogyi Effect shown on Freestyle Libre

[Adam29]

Morning all, I just wanted to share the below to illustrate (what I think is) the somogyi effect. I went to bed with a reading of 8.4 after rising from 6.5 in 45 mins. I did a correction bolus and woke up this morning with a reading of 7.2. So I would've been none the wiser, however the libre clearly shows a drop in blood sugar followed by a rise which I can only explain as a liver dump as I finished eating around 8 o clock.

 

[tim2000s]

Hi @Adam29 , that looks more like a compression low from lying on the sensor as the trend immediately prior to the drop is upwards and if you were to continue the line, it arrives almost exactly at the point where the drop off bounces back to.

If I'm understanding what you're saying correctly, you took rapid acting at about 11pm. The profile of that insulin is unlikely to drive a sudden drop three hours later as it is mostly used up at that point. Normally you'd expect to see that drop off occur from about 60 mins. In addition, a Somogyi effect rebound would tend to be significantly higher than the trendline of the level you were at previously.

 

[BeccyB]

looks more like a compression low from lying on the sensor

I see what you mean but wouldn't the compression be a sudden drop and then a sudden rise again when you move onto/off the sensor?
I've never even considered whether I'm laying on my sensor so worth me bearing in mind - thanks for the tip

 

[tim2000s]

I see what you mean but wouldn't the compression be a sudden drop and then a sudden rise again when you move onto/off the sensor?
I've never even considered whether I'm laying on my sensor so worth me bearing in mind - thanks for the tip

It all rather depends on how you lie on it and the pressure applied. I had a sensor a couple of weeks back where I'd positioned it on my arm such that lying on it in a fairly normal position would cause a smooth decline, and keep it low till I moved off, when it would climb at a rate similar to the climb in the OP's picture. I observed in on numerous occasions. It's more about the amount of pressure.

 

[AndBreathe]

Sorry, sorry for butting in here, as I have nothing to add on the query being asked, but I have a burning question!!

How do you modify the span of the graph you are illustrating? I would dearly love to be able to do that, because my graphs tend to be pretty flat, and with a full 24 hours always on display, the wiggles just resemble a flat line drawn by someone with a slightly iffy ruler!

Thanks in anticipation, and I hope everything becomes clearer in the meaning.

Yours, AB (Data Geek in extremis)

 

[tim2000s]

Sorry, sorry for butting in here, as I have nothing to add on the query being asked, but I have a burning question!!

How do you modify the span of the graph you are illustrating? I would dearly love to be able to do that, because my graphs tend to be pretty flat, and with a full 24 hours always on display, the wiggles just resemble a flat line drawn by someone with a slightly iffy ruler!

Thanks in anticipation, and I hope everything becomes clearer in the meaning.

Yours, AB (Data Geek in extremis)

There are two graphs - the one after you scan, which shows about 10 hours, and the one where you look at the day in review, which is the 24 hour one. That's it.

 

[AndBreathe]

There are two graphs - the one after you scan, which shows about 10 hours, and the one where you look at the day in review, which is the 24 hour one. That's it.

Thanks, Tim. Of curse you are correct. I just got a little over-excited thinking I had missed an available option.

Bother!

Thanks again.

As you were chaps.

 

[Adam29]

Hi guys, thanks for your replies - @tim2000s I had no knowledge on compression lows so good to know. Is there anything else to look out for to give false readings? This is only my second sensor so still learning!

 

[tim2000s]

Hi guys, thanks for your replies - @tim2000s I had no knowledge on compression lows so good to know. Is there anything else to look out for to give false readings? This is only my second sensor so still learning!

That's really the key one to be aware of. It is a valid issue on all CGM sensors, not just the Libre. The other thing is just to make sure you stay hydrated as that's been observed to affect the outcome too.

 

[AndBreathe]

I won't bother asking what this means.......


I'm still alive and functioning, so I'll plump for the alternative!

Ooops. That's a big one!

 

[Brunneria]

Re the question about 'wouldn't a compression low be a sharp drop and then a sharp rise'

- don't think it would be, necessarily.

I have had a couple of bizarre high and bizare low reads on my sensors (sudden hop up 5mmol/l, then back down) again in the space of 5 mins or similar.

These never show on the graph - so the software smooths things out to some extent. That may have happened here. The graph lines always look 'simplified' to me, going fairly smoothly from high point to low, or vice versa. I don't think human bodies work that way, but graphs do, if you get my ghist.

 

[RuthW]

There are other possible interpretations. Your basal may be too high, causing the drop. The rise may not be Somogyi. It may be gluconeogenesis caused by high protein+high fat in your evening meal. You need to see a pattern (or absence of pattern) before interpreting a single event like that.

 

[Ladybirdy75]

Well here I am poised to commit to buying one right now online. Thought I'd come on here and see any reviews so this has been helpful. I'm committing to buying one but I have to say I'm still not really sure if it'll do the job I'm hoping as people seem to either love it or hate it?!!

 

[tim2000s]

Well here I am poised to commit to buying one right now online. Thought I'd come on here and see any reviews so this has been helpful. I'm committing to buying one but I have to say I'm still not really sure if it'll do the job I'm hoping as people seem to either love it or hate it?!!

What do you want it for?

 

[Snapsy]

@Ladybirdy75 I was having a chat with my husband about it this morning - I'm a new Libre user, with my second sensor due to expire on Sunday, so that's nearly 4 weeks' use.

We agreed how very, very much more relaxed and confident I am, just in the last 4 weeks. I'm super-obsessive about numbers, and testing, and am usually in a high state of anxiety 'about the numbers'. I don't view the Libre as an alternative to blood glucose testing, yet I am doing fewer blood tests than before (sometimes only 5 a day rather than 12-14), as I was doing many of my pre-Libre blood tests 'just to see' whether I was high or low, or could I be tired/ill/hungover/in the 3pm 'slump' that I gather is common to the general population, etc etc etc, so I would be doing many more blood tests than I was ever taking action on.

With the Libre, I bip the Smartie (technical term: scan the sensor) often just to see IF I need to test. I can see at a glance if I'm dropping or rising. Often I just then put it down and carry on with my day. Oh, the freeeeeeedom! Sometimes I will tell from the scan that actually I need to do a test, which I'll do without the feeling I've often had in the past that I'm being frivolous with test strips.

I still test before having any insulin, and before driving. THOSE decisions I can only make if I do a blood test, not least because my Libre (both sensors so far) run 20-25% high. That in itself isn't a bad thing because a) I can still see the trend, and b) I do a blood test before doing anything like drive or bolus, so it doesn't matter!

And to think that someone warned me off ordering one of these because they thought it would make me even MORE obsessive about my control - fair point, I guess, but in practice I have found the opposite to be true.

Do report back on how you're finding it, @Ladybirdy75 !