Musings: the 3 am dip

[Radders]

It's well known in diabetes circles that one's blood sugar tends to dip around 2-3 am.

This prompts a few questions for me:

1 how can this possibly be: surely it must depend on a number of variables, e.g. When the last meal was, what time one went to sleep, how deeply one is asleep etc? So why isn't it quoted as, for instance, 7-8 hours after the last meal, or, say, 3 hours after going to sleep?

2 is this natural low what happens in those without diabetes, in which case for those of us with reasonable control of our basal doses, it shouldn't happen?

3 if 2 is true, how do they know?

4 does it depend on the amount of glycogen stores, in which case does it stop occurring in those who eat low carb?

Can anyone with a bit of medical knowledge shed any light on these please, or add any more that I haven't thought of?

 

[Northerner]

It's all to do with the body clock, also known as the Circadian Rhythm. As far as diabetes is concerned, the changes in levels are due largely to the activity of our liver. As you know, the liver trickles out a 'basal' levels of glucose from its stores day and night, but it does this at different rates. Everyone is no doubt familiar with the 'liver dump' we often get when waking, as the liver gives an extra boost to our blood sugar to get us started for the day. The lowest point of liver production is normally around 2-3 am, as daylight is also a factor, and this tends to be when it is darkest (in evolutionary terms). It doesn't have a great deal to do with diet, except insofar as your levels will reflect their starting point, plus the liver action. If you are a night or shift-worker then your rhythm can change in order to match your new sleep pattern, so the 2-3 am rule wouldn't apply.

 

[Radders]

Thank you, I hadn't thought about light levels. I'm surprised they still have much effect on those of us who live surrounded by synthetic blue lights that supposedly trick the brain into thinking it's daylight, plus blackout curtains etc?
Another question: I have noticed that my overnight basal requirement seems higher on days when I have eaten more carbs even taking into account late digestion etc. Is it possible that the liver trickles out more when the stores are full, even though it's not required?

 

[Northerner]

Another question: I have noticed that my overnight basal requirement seems higher on days when I have eaten more carbs even taking into account late digestion etc. Is it possible that the liver trickles out more when the stores are full, even though it's not required?

Just speculation, but perhaps if you have eaten more carbs the fat and protein elements of your diet may take longer to digest and these can also raise levels over a much longer period than carbs? I'm not a real biologist! 😉

 

[HOBIE]

This should be in the normal section & not the pumping ? 🙂

 

[Radders]

This should be in the normal section & not the pumping ? 🙂

I thought about this but plumped for pumping because it's only really since I got my pump that I have been able to fine tune my overnight basal,but I do realise that the way my post turned out it didn't actually relate to pumps!

 

[Lucy Honeychurch]

I've found this thread interesting as I work nights and I'm more insulin sensitive between 12am and 4am and my meter is set to reflect this, also I'm no stranger to the 3am hypo so I always eat something then. My numbers start creeping up after 4am and I often need a correction when I test when I go to bed at around 9am.

 

[Radders]

My typical dip time seems to be about 4 pm!

 

[everydayupsanddowns]

I love Northie's great explanation. Can't remember where I heard it, but I think the drop-off in secretion of Cortisol (and perhaps other counter regulatory hormones) is also connected. These affect the glucose output of the liver I think.

Edit: these are all connected to circadian rhythm, so my half remembering paid off for once!