Understanding basal rates

I’m still pretty new to pumping – I’m about a month into my Minimed Paradigm 722 (with Apidra). I have CGMS.

One area that I’m struggling to understand is basal patterns…

For example, if you go low between midnight and 3, when would you set a lower basal?

Similarly, I exercise in the mornings and need a higher basal during this hour because it’s intense, aerobic + anaerobic, and I always run high unless I bolus – it seems setting a correct basal for this would make more sense.

I haven’t ever noticed having dawn phenomenon in my life, however I have always had issues with night time lows. I’m setting my nightly basal lower, which is ridding myself of the night time lows, but now I start to rise in the early mornings! Maybe I’m leaving the lower pattern on too long. Maybe I should start it sooner? I think I just don’t completely understand the timing with basals!

I should talk to my doc, of course, but I’m really just curious what others do too…

Jaclyn: Seems like you are just beginning to figure out how long it takes for changes in basal rates to become effective. Everyone is a little different. For me, on Novalog, there is about a 1.5-2 hour lag on basal changes. There are others for whom it is shorter or longer.

If I were going low between midnight and 3 am, I would reduce my basal for the period from 10pm to 1 am. If you are rising in the morning, you may need to start increasing the basal beginning around 4 or 5 am, depending on your sensitivity. For me, I start climbing around 6:30 am, so I need to increase my basal beginning at 5 am.

For exercise, everyone’s experience is different, and it depends on the type of exercise. I do either an hour on a spin bike or a mix of fast elliptical and heavy weights, and the insulin needs are different for each. It took a long time with my endo and CDE to figure out a plan for what to do about exercise (halve the basal 2 hours before exercise, then increase it to 125% of normal when exercise starts). Rather than working with trying to program in your different basals, try using the temporary basal feature for exercise. That way, you are not locked in to starting exercise at the same time every day.

You are going to need to figure all of this out, and a large part will be careful record keeping and the info from your CGMS, together with a lot of trial and error. Good luck, and let us know what works for you.

hi Jaclyn, Jonathan has it all covered =) I wanted to add a table of “Typical” (YMMV) basal rates that may help you get a feel for what most basal patterns look like. hope this helps a little:

excerpt from "think like a pancreas" by Gary Scheiner - a very good book and diabetes reference.

Very helpful! Thank you!

I have been using the temp basal feature during exercise, though just not as effectively as I would like (so I have to bolus). Based on what you said, my timing is off.

Starting to exercise was actually one of the main reasons I finally went to the pump. I hadn’t done much exercise in years prior, and when I started up I was having some serious issues with highs (I would end up anywhere from 200 to 400 afterward!). The pump has helped considerably, and now I’m climbing up to around 150-160 during exercise, which of course I’d like to get down more still!

Thanks! Great graph – and not completely what I would expect either. Very interesting.

I’ve seen that book title thrown around a lot, along with the “Pumping Insulin” book. They’re both on my Christmas wish list. :slight_smile:

Interesting. It is clearly a “typical” pattern, but it is nothing like mine. Just shows that we are all individuals. And that we all have different activity levels during the day that impact where our basals need to be. To further complicate it, we may have different carb ratios at different times of day (I have 3 different carb ratios).


I have been on the MM722 for almost 2 yrs and am still fine tuning my basal rates your on the right track keep experminting you will get their.



I do a lot of intense anaerobic workouts, too. I know precisely what you mean about needing more insulin following that type of exercise. Your liver is dumping sugar into your bloodstream and your sympathetic nervous system is highly stimulated from the exercise, both of which push you into hyperglycemia easily. Combine this with the fact that you typically need to lower your basal rates significantly before/during your workout and you have a very difficult balancing act to achieve.

Others in the thread have given you excellent information on timings. I have the same pump as you do, I use Apidra, and I recently got the CGMS. One thing that has been very helpful for me in controlling this situation is the use of Symlin. Symlin does a number of things, but one of them is signaling the liver to stop dumping sugar into your bloodstream. It also slows the absorption of nutrients in your food significantly, which means carbohydrates do not slam you all at once. Non-diabetics make amylin (the natural version of Symlin) along with insulin from the islet cells, so it is another hormone we lack. If you want a serious advantage over diabetes at mealtimes, check out Symlin.

Your CGMS graphs should be showing you where your basals are falling short. Has your doctor downloaded your sensor data and shown them to you? You could make adjustments to the basal rate each night and then check the graph on the pump and see what is going on too.

Good luck!