Definition of Dawn Phenomenon

My BG typically starts rising around 4-5am - when I’m still asleep. It continues to rise after I get up, more so if I do resistance exercises rather than swimming.

My only question is what I should give as my “fasting glucose” number if asked. Is it what my Libre Freestyle shows in the depths of the night, when it’s at its lowest? Or what it is when I get up - which would be the first opportunity I would have to finger prick (if I were doing that, which I’m not.)

Mine is Definitely more towards foot to the floor - starts a steep rise about 30 minutes before I wake between 4:30 and 5am

I find my glucose level stays the same after 7 hours sleep, even if I lie in bed awake for a bit. It only starts to rise when I get out of bed. So foot on the floor for me!

I’ve always thought it partly had something to do with REM sleep patterns. https://www.helpguide.org/harvard/biology-of-sleep-circadian-rhythms-sleep-stages.htm

There always seems to be a correlation with reported BG rises with some of the REM & “sleep state” graphs thrown around the net..
Though I can also have more memorable vivid dreams when I go low at these times too..
Normally a trigger dream wakes me if hypo & of course the low is due to too much basal.

My amateur-hour take is that Dawn Phenomenon and Foot On Floor are separate but similar effects of the daily pattern of hormone secretion.

This is a list of the hormones that affect blood glucose: - Link

Of these, growth hormone secretion is known to be associated with sleep. Perhaps others are too. Asprosin is associated with fasting. Epinephrine (adrenaline) is associated with sudden action or exertion.

So perhaps sleep-associated growth hormone secretion can begin a rise in BG levels during the night. Perhaps asprosin secretion also starts up some time during the night once well into a fasted state. Perhaps a little spike of epinephrine on waking and getting out of bed causes Foot on Floor, and continued, elevated levels of asprosin through the morning cause the continued slow rise in BG until some food is eaten. Or perhaps some similar, continuously changing cocktail of hormones from very early morning through to midday causes both effects and is a little different for everybody.

Mine starts around 3am and will increase until I have a snack to put it in its tracks. However and this is weird, but in warmer weather and in summer, I can get up at 5am and I have been known to get a 4.6. This may be due to more hydration I really don't know but winter months I tend to be in the 6s or 7.5, if I have eaten peanuts

In Response said:

Did your amateur hour find anything to justify the reference to 8 to 10 hours after going to sleep?

Click to expand...

I would be shocked if any clear-cut 8 to 10 hour timeframe applies to a broad range of people, given the wide variety in people's sleep and eating patterns.

My bs definitely rises as I get out of bed ,

For me, the rise doesn't happen until I've been up and about for an hour or two, then it will start climbing and will go way up to 11 or 12 before I either inject and eat or do a small correction if I'm not hungry. No rise during the night, in fact my Libre line is almost flat

ATB123 said:

For me, the rise doesn't happen until I've been up and about for an hour or two, then it will start climbing and will go way up to 11 or 12 before I either inject and eat or do a small correction if I'm not hungry. No rise during the night, in fact my Libre line is almost flat

Click to expand...

What time do you retire to bed when this happens?

I might bed down at 11pm get 7 hours sleep start to get a FotF in the first hour prepping for work, then a further rise driving to place of work before I action on it? (Sometimes I’ve corrected just before setting off.)
That covers 9 possibly 10 hours after my head hit the pillow…
It also depends on what I’m expecting the day’s graft to throw at me..?

Jaylee said:

What time do you retire to bed when this happens?

I might bed down at 11pm get 7 hours sleep start to get a FotF in the first hour prepping for work, then a further rise driving to place of work before I action on it? (Sometimes I’ve corrected just before setting off.)
That covers 9 possibly 10 hours after my head hit the pillow…
It also depends on what I’m expecting the day’s graft to throw at me..?

Click to expand...

Usually go to sleep about midnight, wake up around 7ish, but the rise doesn't start till 9ish. If I'm at home I will just have some breakfast and inject, if at work and first break isn't till 11, I will correct. Bodies are such strange things, seems like our all do things differently

Exercise will reduce or eliminate both my dawn phenomenon (i.e. gentle rise from ~3am) and foot on the floor (I see the very strong upward trend on the CGM once I've put the kettle on.)

Interestingly the gradual dawn phenomenon part doesn't occur at all if I've done any reasonable exercise (say an hour of cycling or a couple of hours of badminton) in the preceding days (so perhaps 3 or 4 days at a guess), but the dawn phenomenon is only reduced if I either restart exercise after a break or do lots of exercise (e.g. very long ride) while also doing normal exercise (and in the latter case my DP goes away completely and tapers back in over a couple of days.) Once I get used to the (normal) exercise, the foot on the floor annoyingly goes back to normal.

I think what I'm calling DP is actually a combination of a very slight BG rise caused by hormones but also the fact that when I don't manage to exercise (work, weather, slipped on my daughter's book and fell down the stairs - ouch!) I will run higher across the day so should really take more basal. It just so happens that my residual bolus tapers off around 3am (as I usually split dose for supper and often do a correction dose before bed), which otherwise hides the fact that the large rises I'm seeing now are probably mainly down to requiring more basal (or exercise!)

I don’t know what my DP is up to. I take my FBG as soon as I’ve washed my hands and then if I take it again 10 minutes later it’s gone down by at least 1mmol for instance this morning it was 7.5mmol at 7:10, I took it again at 7:20 and it was 6.1! It then starts to rise after about 20 minutes. I’d have no change if that mammoth was waiting for me outside my cave!

ATB123 said:

Usually go to sleep about midnight, wake up around 7ish, but the rise doesn't start till 9ish. If I'm at home I will just have some breakfast and inject, if at work and first break isn't till 11, I will correct. Bodies are such strange things, seems like our all do things differently

Click to expand...

Though we are different, there does seem to be a correlation within 10 hours of starting the sleep cycle. (Eyes closed & imobile.)

In answer to the initial question. Upto 8 to 10 hours after getting my head down with some category of liver dump? I see no issue or loose any sleep with the wordybits…

Jaylee said:

Though we are different, there does seem to be a correlation within 10 hours of starting the sleep cycle. (Eyes closed & imobile.)

In answer to the initial question. Upto 8 to 10 hours after getting my head down with some category of liver dump? I see no issue or loose any sleep with the wordybits…

Click to expand...

Interesting. I find it difficult to sleep earlier than midnight, but if I do get my head down a couple of hours earlier I shall watch for an early morning rise!