When changing basal rates, how long before the change is effective?

i know that this discussion has come up before, and i know that it is somewhere in the John Walsh book, but i simply can’t remember and i thought i would put it out there for my own info (and all of yours who do not know)

my basal profile needed to be increased due to “normal” D changes from too many high BGs.
i went from:

  1. 12am .50
  2. 7am. .45
    3 6am .50
    up to :
  3. 12am: .55
  4. 7am: .50
    3 6pm: .55

this was too high an increase for me. I am very insulin sensitive.
so i lowered it this morning before i ate lunch. (i had been continuing to go below 80 no matter how many G tabs i took)

so i lowered the rates again, but only by.25 for each basal rate.

here’s my question: how long will it take before i notice this change in my basal rates? will it be immediate, or will it take approximately 2 hours?

I allow 2 hours for the change to take effect. But it can depend on how good absorption is at the infusion set site. Also if I am changing on the fly, as I often do, it can depend on IOB.

thanks Annabella. i made the basal changes w/out any IOB about 2 1/2 hours ago. i ate 1C Oatmeal and bloused for the carbs. i am holding steady at 97, and i will see if there is any spiking later on.

Pretty much what Annabella said. For example, when I need to reduce my basal rate for activity, it needs to be happen at least an hour ahead of time, and typically I slow it down for about 3-4 hours, dependent on the expected activity duration.

You cannot judge the efficacy of a basal change if you ate and bolused.

Basal rate changes are NOT immediately noticeable. If they are, it’s an illusion. seriously.

why wouldn’t changed basal rates be immediately noticeable? well, I’m not sure what’s considered immediate, certainly within 1 - 2 hours, no? It’s fast acting insulin. Otherwise, why would everyone be doing temp basal rates or changing them all the time? I was told basal rates should be changed typically an hour before the need but I guess it does depend on how one absorbs insulin, etc…

if you want to consider 2 hours as “immediate” than so be it. that’s not my definition, but let’s not quibble. Doing temp rates and “changing them all the time” has nothing to do with “immediacy”. One must THINK AHEAD. An hour or two generally works when you want basals to help level out your bg’s. don’t expect this to work as planned when you have IOB. Lots of factors to consider when adjusting insulin intake via basal and bolus methods.

doesn’t matter if we’re on MDI or pump, yes…we all have to plan ahead and the beauty of the pump is the use of ‘fast acting’ (subjective I guess) and not the long acting.

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i know that i must have screwed it up, b/c i lowered my basal rate before eating 1C of oatmeal (but no IOB at the time ) however, my BGs stayed steady all day long and did not dip below 80 (which is my designated low). i remained at around 95 throughout the day. and by dinner time i was 112. no lows at all today since i lowered my basals (not yet anyway) and no highs either. so, perhaps what i chose for myself was a success. (?) then, w/out IOB, i pre-bolused for dinner. chicken, one of my favorites that i cook to perfection, so we’ll see how that goes.

thanks for al the info.


i’m interested in this topic as I (again) am REstarting on my pump this tuesday. I thought you mentioned Daisy Mae that you’re pumping about 10 units total for basal, really insulin sensitive (as am I) but your rates seem like way more then that, no?

my most current exact total basal per day is 12.05 units. i have 3 different basal rates
12am .50
7am .475
6pm .50

then, an average total of units per day will come to anywhere between 18 units to 22 units. (this may have changed slightly since my last post.)

The very definition of YDMV (Your Diabetes May Vary)!

When we pool our experiences together we come up with a general idea of what to expect, but that doesn’t mean that any of us is the exact average of all of us!

Congratulations on your adjustment! My only advice is to stick with it through a few days, maybe a week, so you can see how it fits with different meals, different sleep, and different activity levels.

sticking w/ it is the key. under different circumstances, i get different outcomes. today i spent from 6am till 9 pm in the Hospital for Special Surgery. my husband was having a total hip replacement. it was a long, tedious, and exacerbating, anxiety producing day. my BGs were good in the morning and after breakfast, but then as my heart started to pound, my BGs started creeping up. it was past lunch time and i was ravenous but not yet able to eat anything. also, there was no cafeteria in the hospital. i finally was able to find a kiosk where i got a Fage plain yogurt and a cup of tea. under normal circumstances, this would be a snack and not raise my BGs by any significant amount. but as my anxiety increased, so did my BGs. i pre-bolused and started a temp basal of 105%. w/in half an hour, my BGs climbed to 202. i raised my temp basal to 110% and took a pill to relax. i did some deep breathing exercises. i felt like i was going to have a heart attack. it took all day to get my BGs back into a nice normal range. i lowered my temp basal back down to 105% and thought i would see how that worked for me.

so, now i sit here, home from the hospital, having eaten a 3 egg omlette with a cup of warm milk (very soothing), and am waiting to see what my BGs will do over night. up? down? in-between? just right and steady? who knows? hoping for the best…good night all.

Daisy Mae