Why is overnight fasting necessary for a blood test?

Brunneria

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What's a "false hypo"? :>

There is a belief that you only have a hypo when your blood glucose drops below 4.*

However, if your body is used to running with high sugar levels, then it gets used to it.

If your BG drops sharply, this can trigger 'false hypo' symptoms even when your BG is above the magic number of 4. In that case, it is the sharp drop that triggers the body's reaction, because the BG itself is not particularly low.

Did that make sense? If not, one of the sciency boffins may be able to explain it better.

*i disagree with this. Having had a lot of these so called 'false hypos' I am convinced that some of them are the real deal.
 

Spiker

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*i disagree with this. Having had a lot of these so called 'false hypos' I am convinced that some of them are the real deal.
I agree with you. The adrenalin response (when it works) is more sensitive and more accurate than a meter. The meter is taking a static value of peripheral blood that is delayed vs arterial blood and is subject to various errors. The adrenalin reaction responds strongly to the drop rate of blood glucose, not just the absolute level of blood glucose. In the face of hypo symptoms I trust the symptoms over the meter, if they conflict. If nothing else it's better to be safe than sorry.
 
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PaulinaB

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There is a belief that you only have a hypo when your blood glucose drops below 4.*

However, if your body is used to running with high sugar levels, then it gets used to it.

If your BG drops sharply, this can trigger 'false hypo' symptoms even when your BG is above the magic number of 4. In that case, it is the sharp drop that triggers the body's reaction, because the BG itself is not particularly low.

Did that make sense? If not, one of the sciency boffins may be able to explain it better.

*i disagree with this. Having had a lot of these so called 'false hypos' I am convinced that some of them are the real deal.

Ahhh, that stuff. I had that initially, but those went away after I got my sugars average below 10 :) But it did felt very real at times.
 
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Brunneria

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Like a "real" hypo :) It's just your sugar is above 4 not below.

Lol. Yes.

I think we all experience hypos slightly differently. Are you asking what they are like, or how they differ from so called 'real' hypos?
 

Bluetit1802

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I'm asking what they are like and what the symptoms are. I have been down to 4 a few times but haven't felt any different. I'm not on any meds.
 

PaulinaB

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I'm asking what they are like and what the symptoms are. I have been down to 4 a few times but haven't felt any different. I'm not on any meds.

Well, you sweat, tremble, feel weak, confused, etc. If you have the symptoms, you're going to notice them :) Other thing is you may have hypo unawareness. But you may not be going actually hypo at all if you're not below 4 and/or there's no sharp drop in your BG.
Since you're T2 on diet & exercise, it's very unlikely you'll go into hypo (from what I know).
 
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Brunneria

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Sorry Bluetit, just read your last posts and realised what you are asking.

If, at any point during the experience, I eat something carby, the symptoms ease then disappear, but I usually feel weird for a bit, even if I catch it at an early stage.

Ok, my particular brand of hypo usually follows this route (I will describe a bad one, but I very rarely get them like this, since I became diabetic. I used to get them a lot more often when I was hypoglycaemic, then pre-diabetic. it is one of the reasons I prefer being diabetic to then!):
  • Subtle loss of concentration
  • Slight zoning out/vagueness
  • Mistakes in judgement
  • Slow or clumsy reactions
As it gets worse, all the above get worse, plus
  • A weird disconnect between hearing what people say and actually understanding it
  • Numb cheekbones (this is the best clue I have that there is a problem, and I have learned to heed it!)
  • Heaviness in the limbs
  • Lack of energy/lethargy
  • Apathy, hopelessness
  • Black misery
Physical exertion or stress (even walking up a few steps) can make all of them get worse, very, very quickly.

At some point, my body notices that there is a problem and goes through a complicated series of steps to cause glucose be dumped into the bloodstream as an emergency. One of these steps (I have a very rudimentary understanding of the process), uses adrenalin.
  • I go white - Morticia white
  • my hands and knees shake
  • I feel hollow
  • I feel off balance and
and if there is anyone around me, breathing in my direction
  • I experience the most terrifying RAGE. like PMT - irrational fury. Poor Mr B is rather nervous of this stage. with good reason. I have had to work really REALLY hard at not physically attacking him, and some of the things I have said. Vicious, venomous... they have been awful. he recognises the signs nowadays (it has only been really bad about 4 times in 6 years) and he know to leave - the room, the floor, the building, as necessary. We have actually discussed the best exit strategy, for the next time.
Even if there is no one else around, I probably realise at this point that there is a problem, and eat something. usually high carb. usually a feeding frenzy.

The aftermath is piteous misery, all over aches, weird, jangly blood glucose levels and excessive highs and lows for up to 3 days. Weepy depression, slowly easing as time passes.
 
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Spiker

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In the last one - two minutes...

White noise
Inability to see the location of objects right in front of you.
Unable to tell the location of one object in relation to another even though they are right in front of you
Sense of weightlessness
Intense fear
Tunnel vision
Breakdown of the visual field
(sometimes) Blindness (temporary)
Unconsciousness

I would not wish it on anyone. I hope you never have one.


Sent from the Diabetes Forum App
 
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Brunneria

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In the last one - two minutes...

White noise
Inability to see the location of objects right in front of you.
Unable to tell the location of one object in relation to another even though they are right in front of you
Sense of weightlessness
Intense fear
Tunnel vision
Breakdown of the visual field
(sometimes) Blindness (temporary)
Unconsciousness

I would not wish it on anyone. I hope you never have one.


Sent from the Diabetes Forum App

Did you have any warning? Any chance to react?
Thank god mine are so much less severe, but then, as a t2, they would be.
 

Spiker

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Did you have any warning? Any chance to react?
Thank god mine are so much less severe, but then, as a t2, they would be.
Oh yes thankfully lots of warning, usually. But the frustrating thing is that even with 5-15 minutes warning it doesn't always prove possible to get enough glucose on board to avert the hypo. Those 5-15 minutes are very distressing if the glucose isn't working.
 
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Brunneria

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Oh yes thankfully lots of warning, usually. But the frustrating thing is that even with 5-15 minutes warning it doesn't always prove possible to get enough glucose on board to avert the hypo. Those 5-15 minutes are very distressing if the glucose isn't working.

And how do you feel for the next couple of days?

I suspect that most of my (I will call it a) hangover, from a hypo is the effect of the adrenalin reaction. Sort of like shock.

Do you miss that joy? Or get it worse - because the experience itself is worse?
 
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This is not a competition to try and burn glucose off before the test by exercising, it is to try and establish if you have normal BG control under standard conditions, or if you have some kind of problem.

I didn't mean to imply there was a competition and neither do I try to beat any test since I would be the only one to suffer. However, the phrase "standard conditions" barely applies since it only takes account of when I last ate and not when I got up, what work I have done that day or the lateness of the appointment at the surgery.

If it is of any value then I am happy to join in but I would like more of those standard conditions to apply.
 

Spiker

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And how do you feel for the next couple of days?

I suspect that most of my (I will call it a) hangover, from a hypo is the effect of the adrenalin reaction. Sort of like shock.

Do you miss that joy? Or get it worse - because the experience itself is worse?
I feel knackered for the next day or so, depending on the severity. I think it feels like having run a half marathon (without training!) and for the same reason: glycogen is heavily depleted and needs to be stocked up. I think the body prioritises that restocking of glycogen and just shuts you down until it's done. That's my theory anyway.

If I actually lose consciousness the after effects are worse. That feels like someone has worked me over with a baseball bat, in addition to the exhaustion. Every muscle aches. That's from having a fit.

Sent from the Diabetes Forum App
 
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Spiker

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If it is of any value then I am happy to join in but I would like more of those standard conditions to apply.
I think the only definite value in the random BG is to make sure that other blood tests they take at the same time are not invalidated by an out of range BG. Otherwise I agree with your point, it's pretty meaningless.
 

Bluetit1802

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[
In the last one - two minutes...

White noise
Inability to see the location of objects right in front of you.
Unable to tell the location of one object in relation to another even though they are right in front of you
Sense of weightlessness
Intense fear
Tunnel vision
Breakdown of the visual field
(sometimes) Blindness (temporary)
Unconsciousness

I would not wish it on anyone. I hope you never have one.


Sent from the Diabetes Forum App




Sorry Bluetit, just read your last posts and realised what you are asking.
If, at any point during the experience, I eat something carby, the symptoms ease then disappear, but I usually feel weird for a bit, even if I catch it at an early stage.
Ok, my particular brand of hypo usually follows this route (I will describe a bad one, but I very rarely get them like this, since I became diabetic. I used to get them a lot more often when I was hypoglycaemic, then pre-diabetic. it is one of the reasons I prefer being diabetic to then!):
  • Subtle loss of concentration
  • Slight zoning out/vagueness
  • Mistakes in judgement
  • Slow or clumsy reactions
As it gets worse, all the above get worse, plus
  • A weird disconnect between hearing what people say and actually understanding it
  • Numb cheekbones (this is the best clue I have that there is a problem, and I have learned to heed it!)
  • Heaviness in the limbs
  • Lack of energy/lethargy
  • Apathy, hopelessness
  • Black misery
Physical exertion or stress (even walking up a few steps) can make all of them get worse, very, very quickly.
At some point, my body notices that there is a problem and goes through a complicated series of steps to cause glucose be dumped into the bloodstream as an emergency. One of these steps (I have a very rudimentary understanding of the process), uses adrenalin.
  • I go white - Morticia white
  • my hands and knees shake
  • I feel hollow
  • I feel off balance and
and if there is anyone around me, breathing in my direction
  • I experience the most terrifying RAGE. like PMT - irrational fury. Poor Mr B is rather nervous of this stage. with good reason. I have had to work really REALLY hard at not physically attacking him, and some of the things I have said. Vicious, venomous... they have been awful. he recognises the signs nowadays (it has only been really bad about 4 times in 6 years) and he know to leave - the room, the floor, the building, as necessary. We have actually discussed the best exit strategy, for the next time.
Even if there is no one else around, I probably realise at this point that there is a problem, and eat something. usually high carb. usually a feeding frenzy.
The aftermath is piteous misery, all over aches, weird, jangly blood glucose levels and excessive highs and lows for up to 3 days. Weepy depression, slowly easing as time passes.



Blimey. I wish I hadn't asked now! Thank you Brunneria and Spiker. I can't imagine how horrible it must be. I know Type 1's carry glucose round with them wherever they go. Do you think Type 2's should also do this, whether on meds or not?