• Guest - w'd love to know what you think about the forum! Take the 2026 Survey »

Might hot weather cause low glucose at night?

R

Rosie9876

Well-Known Member
Messages
267
Type of diabetes
Type 2
Treatment type
Tablets (oral)
After a long period in hospital, I've had trouble controlling my blood glucose, but I've kept persevering on my 2 x 500 Metformin and low carb regime. Then suddenly over the past few days, my BG has not only improved, but has been dropping too low - as low as 2.9 once, just before bed.

Even though hypos shouldn't be an issue on Metformin, I took a swig of maple syrup just in case, and it came up. But the next day, my CGM showed I'd been below 3.9 for an hour that night, dipping down as low as 3.0.

Same this night - 2 low episodes. I'm trying to stay hydrated, but should I worry? Increase carbs? Poor sleep has been a problem, but also before these dips. And my Libre 2 plus has been quite accurate lately, so I believe the readings. Any thoughts? TIA
 
Do you have symptoms of a hypo when the readings are low, such as shaking, sweating, feeling confused or even a racing heartbeat?
 
Rosie9876 said:
After a long period in hospital, I've had trouble controlling my blood glucose, but I've kept persevering on my 2 x 500 Metformin and low carb regime. Then suddenly over the past few days, my BG has not only improved, but has been dropping too low - as low as 2.9 once, just before bed.

Even though hypos shouldn't be an issue on Metformin, I took a swig of maple syrup just in case, and it came up. But the next day, my CGM showed I'd been below 3.9 for an hour that night, dipping down as low as 3.0.

Same this night - 2 low episodes. I'm trying to stay hydrated, but should I worry? Increase carbs? Poor sleep has been a problem, but also before these dips. And my Libre 2 plus has been quite accurate lately, so I believe the readings. Any thoughts? TIA
Click to expand...
I get cliff-edge drops in BG occasionally overnight which started around 2014.

What would happen would be nightmares, heavy sweating, waking confused and disoriented. Usually around 4-5am, I'd never associated them with T2 until using a CGM. The sweats/nightmares correlate with sudden BG drops. It's been suggested to me that it wasn't a "real hypo" and the CGM was only showing pressure lows, but that doesn't explain the exact correlation with the sweats and nightmares. And I do get very occasional hypos in other circumstances.

What then happens is that my BG slowly and steadily recovers and will continue to rise slowly for at least 12 hours, without food.

These days I don't seem to get them as badly or as often but there are still regular episodes where I'm totally soaked.
 
Antje77 said:
Have you confirmed with a finger prick?
My Libres always read lower than blood so I only believe a hypo when a fingerprick says the same or when symptomatic.
Click to expand...
I can't get the knack of finger prick, so rely on comparison when it's done in hospital. (I was a long stay inpatient and now have outpatient visits.) My Libre sensor used to be quite inaccurate - like you, typically read lower than bloods - but lately the sensors have been more accurate, even predicting my A1c. Three of the 4 lows I've had have been when I was asleep. One actually woke me up at c. 04:30, feeling unaccountably strange. I don't pay as much attention as I would if hypos were a known risk, but the common thread here is the heat and I wonder if it can cause BG to drop too much, even if hypos aren't normally a risk. My alarm for lows doesn't work, and when the sensor was inaccurate, it was a nuisance anyway. But having a low while asleep sounds quite scary. Having said which, they corrected sooner or later.
 
KennyA said:
I get cliff-edge drops in BG occasionally overnight which started around 2014.

What would happen would be nightmares, heavy sweating, waking confused and disoriented. Usually around 4-5am, I'd never associated them with T2 until using a CGM. The sweats/nightmares correlate with sudden BG drops. It's been suggested to me that it wasn't a "real hypo" and the CGM was only showing pressure lows, but that doesn't explain the exact correlation with the sweats and nightmares. And I do get very occasional hypos in other circumstances.

What then happens is that my BG slowly and steadily recovers and will continue to rise slowly for at least 12 hours, without food.

These days I don't seem to get them as badly or as often but there are still regular episodes where I'm totally soaked.
Click to expand...
You make some interesting points. "Pressure lows" doesn't explain what happened to me because the first of my lows happened at midnight, just before I went to bed.
 
Rosie9876 said:
You make some interesting points. "Pressure lows" doesn't explain what happened to me because the first of my lows happened at midnight, just before I went to bed.
Click to expand...
I agree. It's not just a low reading on the machine - it's a collection of things which are normally understood to be features of hypos. A forum member suggested to me that rather than the initial factor being a drop in BG, it could possibly be explained by a sharp rise in insulin, which then would produce the low BG as a consequence.

I've not been able to find anything published that might help to explain. Instead, you will find assertions that "T2s don't have hypos unless on glucose-lowering medication" and suchlike. Interestingly, this piece of research

Continuous Glucose Monitoring Profiles in Healthy Nondiabetic Participants: A Multicenter Prospective Study - PMC

Use of continuous glucose monitoring (CGM) is increasing for insulin-requiring patients with diabetes. Although data on glycemic profiles of healthy, nondiabetic individuals exist for older sensors, assessment of glycemic metrics with new-generation ...
pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov

which was intended to demonstrate what "normal" looked like for CGM use, also demonstrated sharp night-time falls in BG for some participants. The researchers noticed it, couldn't explain it, and ignored it.
 
KennyA said:
I agree. It's not just a low reading on the machine - it's a collection of things which are normally understood to be features of hypos. A forum member suggested to me that rather than the initial factor being a drop in BG, it could possibly be explained by a sharp rise in insulin, which then would produce the low BG as a consequence.

I've not been able to find anything published that might help to explain. Instead, you will find assertions that "T2s don't have hypos unless on glucose-lowering medication" and suchlike. Interestingly, this piece of research

[URL.⁷ therunfurl="true"]https://pmc.ncbi.nlm.nih.gov/articles/PMC7296129/[/URL]

which was intended to demonstrate what "normal" looked like for CGM use, also demonstrated sharp night-time falls in BG for some participants. The researchers noticed it, couldn't explain it, and ignored it.
Click to expand...
Very interesting. Especially that they noticed something, couldn't explain it, and ignored it. I agree, I can't understand your cliff-edge BG drops as anything but real hypos, which suggests we have to stop assuming that we, who aren't on glucose lowering medications, are immune from them. And that's a big deal.
 
Rosie9876 said:
After a long period in hospital, I've had trouble controlling my blood glucose, but I've kept persevering on my 2 x 500 Metformin and low carb regime. Then suddenly over the past few days, my BG has not only improved, but has been dropping too low - as low as 2.9 once, just before bed.

Even though hypos shouldn't be an issue on Metformin, I took a swig of maple syrup just in case, and it came up. But the next day, my CGM showed I'd been below 3.9 for an hour that night, dipping down as low as 3.0.

Same this night - 2 low episodes. I'm trying to stay hydrated, but should I worry? Increase carbs? Poor sleep has been a problem, but also before these dips. And my Libre 2 plus has been quite accurate lately, so I believe the readings. Any thoughts? TIA
Click to expand...
Once again, woken up by low glucose. CGM shows it's been hovering since about 03,00, with 4 episodes, 3 lasting about 15 minutes, the 4th maybe half an hour Feeling nauseous, woozy, blurry. To be clear, I am T2D on Metformin and low (not no) carb regime. I am not dieting to lose weight. This is the third night in a row this has happened. It's quite scary

Edited. BG has gone up to 4.8 now.
 
Last edited:
Back
Top