Different Basal Rates in 1 Day

Hi. I'm reading different information on which hours are good to divide up the basal rates in 1 day.

This is what I'm thinking of using for time slices:

12am-3am (3 hours)
3am-7am (4 hours)
7am-12pm (5 hours)
12pm-6pm (6 hours)
6pm-12am (6 hours)

Does this look about right? What is everyone else using here?


I will let the pumpers chime in on this (and they will, rest assured). But everything I have heard indicates that the answer to this is highly individual. Each person's pattern is specific to that individual. And, just to complicate the picture even further, a person's pattern can vary with weather, illness, exercise, stress, etc.

No matter what you do, diabetes is always something of a moving target. Isn't this fun?


I hate to say this..but it really is an individual thing....do you perhaps have a cgm where you can trend your patterns? When I download my readings..I look at what my hourly averages are to see where the problems areas are and adjust the basal rates accordingly. Currently I only have 4 different basal times set in a 24 hr day. Sadly there is no cookie cutter answer.

Alright this is gonna be a long reply, but very detailed. (Wall-of-text incoming!)

As david and krztina have said, its an individual thing. You don't dictate your basal needs, your body does :) The first step is to find out EXACTLY what those basal needs are. Here's what I did:

First, split the day into three 8 hour segments ( I used midnight-8am, 8am-4pm, 4pm-midnight).

Next, the testing procedures are the same for all three segments: Start each segment so that your last bolus or food was 2 hours prior, 3 is best. This way there is no IOB or food waiting to digest when you begin your test. Try and start the test with a reasonable BG (For me that means between 100-150. Its really not relevant for this test, just be at a reasonable range).

For the next 8 hours, follow your normal schedule. Drinking water is fine, but avoid ANYTHING that would or could alter BG (caffeine, food, etc). Test every hour and track your results. Don't correct your BG at all, unless its health threatening. If you drop to 80, fine. If you rise to 210, fine. Just track the results. At the end of your 8 hour period, eat (you will be hungry haha) and correct any highs.

Do this test 3 times per 8 hour block. So, that will be a total of 24 tests (this took me about 6 weeks to complete). Yes, there will be a few nights where you have to get up every hour.

Once you've got all 24 test blocks done, merge and study the results for each 8 hour block. You should see a trend (i.e. slight rise or drop at about the same time each test period, BIG rise or drop in a certain time period, etc).

With this data, you should be able to determine when basals need to rise or lower, and by how much (you should have already done testing for I:C ratio, and how many BG points 1 unit will drop you). Depending on what insulin you're using, adjust your basal PRIOR to the rise or drop (to accommodate the time it takes for insulin to start working). For example for me, at approx. 4am every morning, my BG rose drastically (dawn phenomenon). I use novolog, so increased my basal starting at 3:15am.

So, after all your tweaks, this will be your rough draft or beta basal. You aren't quite done yet :) After your tweaks, you will repeat the test one more time to confirm your adjustments are accurate. If you have a rise or fall AFTER your tweaks are out into place of more than 20 points, repeat the test AGAIN to confirm the rise and fall again, and adjust, if necessary, as needed.

This is a very long test; however, in most cases, you only need to do it once. Once your pump is set up you can forget about it and feel confident that no matter what time of day it is your insulin needs will only be determined by activity or food/drink intake. It took me a total of almost 3 months to get my basals all set up, but now I could literally fast for 24 hours and my BGs wouldn't budge more than 20 points at any given time of the day.

That's it! That's how to do a proper basal test. I suppose you could set the day up into four 6 hour blocks, but IMHO this would just take longer to complete. Let me know if you have any questions or something didn't make sense-

Great reply!

I think Dan's answer nailed it!

Thank you very much Dan. I will give this a try to fine tune my rates. :)

what about gastroparesis? would that make bg more unpredictable? yes.......i think so
& more difficult to set basals

ok, I'm a chicken and a scaredy cat and neurotic, but I just don't think I could do this Dan. is there any more gentle way of doing a basal test? and under what conditions do most ppl do it, I mean, those who aren't obsessive/compulsive about their d? I feel I'm doing ok, I could probably tweak some basals though.

I have a really dumb question, Anthony. Is there a doctor or nurse that can train you on basal rates? That's how I started with my pump 2 years ago and they kept an eye on me and then adjusted the rates not the times as needed. I am in Canada but I feel like there should be someone that can help you.

Yes, they did help me adjust in the beginning months, and that was helpful. But by far the greatest help was when I started using the Dexcom. Then I was able to really fine tune my basal rates. Right now my rate is the same for most of the day, except for the early morning hours where I require a bit less insulin. The dexcom showed me exactly when my sugars rise and drop at times when there was no IOB and no food in my stomach. Thanks!

I've never done a proper basal test, Marie. I just keep records of my blood sugars and when I see a pattern of highs (or lows) at a particular time unrelated to meals, I tweak the basals for the time zone starting two hours before the problem.

There are several books written by CDEs that are may pumped use as go to bibles.
Think like a Pancreas by Gary Scheiner,
Pumping Insulin by John Walsh.

They both have websites with lots of information.
Gary Scheiner has a practice that will help you manage your pump settings and they can do it via phone or Skype if you are not local.


John Walsh has a site as well


yes it's a lot of fun
we do the best we can from day to day

I don't think there is any way around this type of test for setting basal rate. You need to figure out how your body responds to insulin without the complication of food. If you follow Zoe's advice I think you will be tweaking forever.

We're each individual, Khurt. I think perhaps you are right in terms of someone just starting out trying to ascertain basal rates with little to go on. For those of us with relatively stable basal rates, the occasional tweaking is a fairly easy matter. Though to be honest I remember just reducing my basal (25%?) when I started my pump, then dividing it among the 24 hours, then doing relatively minor tweaking to get it the way I want it. I was, and am, hardly "tweaking forever". But like everything, we are all very different and the adage of "YDMV" means you can follow Zoe's advice, or John's or Jorge's and see what works for you.