We hear it over and over again. Basal is the foundation of T1D management. If you don’t have your basal set correctly, nothing else will work properly. So, you bit the bullet and decided to learn how to basal test. You successfully managed a test and you’ve set your basal perfectly according to that test. So, why are your bg numbers worse than they were before?
I am not a doctor or medical professional. This article is for informational purposes only. If you are thinking about changing the way you treat your diabetes, consult your medical team for assistance.
A quick note before we start:
Basal insulin is used differently with looping systems. That’s where the insulin pump and CGM “talk” to each other and make adjustments without user input. This article is not about how basal works with looping.
It’s not you, it’s diabetes.
It’s fairly common for basal testing to throw things off a bit. There are completely logical reasons why it happens. Luckily, they’re simple to identify and once they’re fixed, you’ll be on an exciting path toward non-diabetic blood glucose numbers.
First, let’s back up a bit and talk about what basal insulin is, what basal insulin’s role is in T1D management, and how to test whether or not it’s doing what it is supposed to be doing.
What is basal insulin?
Everyone needs insulin to live. For most people, the beta cells in their pancreas produce as much or as little insulin as needed 24/7. People with type 1 diabetes don’t produce their own insulin, so they have to take synthetic insulin subcutaneously. The insulin that they take can be split into two categories: basal insulin and bolus insulin.
Whether you’re getting your basal via MDI (multiple daily injections) or an insulin pump, basal is your “background” insulin. This is insulin that you need no matter what. It doesn’t matter if you’re eating large meals. It doesn’t matter if you’re eating extremely low carb or even fasting for long periods of time. Everyone needs background insulin regardless of what else is going on in their day-to-day life.
For people on MDI, this is the long-acting or ultra-long-acting insulin that is given once or twice a day. There are several different brands that have different durations and peaks. Make sure that you understand the profile of your basal insulin so that you can optimize its effectiveness.
Alternately, people who use insulin pumps use rapid-acting or ultra-rapid-acting insulin as their basal. One or more basal rates are entered into the pump by the user or their doctor and the insulin pump administers a continuous supply of basal insulin based on those settings.
The role of basal insulin in T1D management
The truth is, basal insulin has one job: to keep bg steady in the absence of other factors.
Our bodies need glucose to function. Our brains need it. We need it to breathe, to think, and for our hearts to keep beating. Basal insulin covers those basic functions (and more).
That means, no matter what you’re eating or what you’re doing, you need basal insulin.
It is a constant that is silently working in the background. And if you have it set correctly, it should not cause any roller coaster numbers.
What is a basal test?
A basal test is an experiment of sorts. You want to see if your background insulin is doing its job. So, you have to set the conditions in a way that you can observe your basal without anything else clouding your view.
You’re essentially removing food, bolus insulin, and excessive activity from the equation and then watching how your basal insulin behaves. Does it keep your bg steady? Does it pull down over time? Or go up?
Steady indicates on-point basal rate(s). Pulling down shows heavy basal. And, of course, rising bg shows light basal.
For more detailed instructions, you can read the following article: Basal Testing: The Beginner’s Guide
After you’ve successfully basal tested
You’ve done the tests. You’ve tweaked your basal rate. And then tested again. Finally, you’re getting a steady line when you do a basal test. You know for sure, 100%, that you’ve got it set correctly.
But, your numbers are even more out of control than before. What on Earth has happened?
Well, it’s true, basal is the foundation of T1D management. But you still have to build upon it. And what you’ve built leading up to this point was on a shaky foundation. Now, it’s starting to crumble.
The thing is, testing your background insulin is a great step, but it’s just that… one step. There are more steps to take in order to get to non-diabetic numbers.
What is going wrong?
It’s quite simple. With an unsteady foundation, you’ve learned several habits along the way to compensate. Those habits were serving you in a way, but now that you’ve corrected your background insulin, they’re becoming a hindrance.
This is largely because most doctors don’t have enough data to manage T1D particularly well. So, they see an issue with bg numbers and slap on the quickest bandaid that they can think of.
Bg steadily declining overnight? Give a “bedtime snack” to keep it up longer. Bg rising throughout the day? Jack up the insulin-to-carb ratios for meals.
But the fact is, in many cases, the problem was the basal rate. So you end up with an incorrect amount of background insulin and then create a new problem on top of it.
And the best part? Since this is how many doctors deal with basal issues, patients (and their caregivers) learn that these quick fixes are the best way to deal with roller coaster numbers. Even though these bandaid solutions often are the cause of difficult to manage and seemingly inexplicable numbers.
If you’ve basal tested and are sure it’s set correctly, but your numbers have gotten worse since making the adjustment, here are some of the top culprits to watch out for.
If you needed to increase or decrease your basal:
Regardless of whether you adjusted your basal rate up or down, these are probably also going to need some tweaking.
Insulin-to-carb ratios
Insulin to carb ratios, ICR, carb ratios. Whatever you call them, they indicate the number of grams of carbs that you can eat when given one unit of insulin. If your ICR is 15, for instance, 1 unit of insulin will cover 15 grams of carbs. Everyone has different insulin-to-carb ratios and many people have multiple different ratios throughout the day.
It’s rare for people to do an ICR test, but it can be done fairly easily. Unlike basal testing, you don’t have to set much up to do an ICR test. It’s good to do one for breakfast, one for lunch, and one for dinner as many people have different ICRs for different times of day.
If you do an ICR test, you will find your baseline ICR. Once you have that, you can start adjusting a bit for different macro profiles and different levels of activity.
In general, if you needed to increase your basal, you’ll probably need to decrease your bolus amount at meals and vice versa. This is because you’ve been unknowingly compensating for light or heavy basal with your boluses.
Insulin sensitivity factors
On a personal level, I think ISF is mostly useless (aside from looping systems). Most of the time, when you’re needing to correct a high bg, it’s at least partially to do with food (protein rises most commonly). That means that if you use your ISF without accounting for the food that is still affecting your rising bg, it won’t work very well.
Nevertheless, there are times when just your ISF is needed. And like carb ratios, you might have been compensating for heavy or light basal with your ISF. So, after adjusting your background insulin, you might find that your ISF is either extremely strong or is doing next to nothing to impact your bg.
ISF can also be tested. It’s quite simple, but most people don’t have the right circumstances very frequently. You might have to intentionally create an environment that is good for ISF testing.
Like the carb ratios, your ISF is likely to need an adjustment in the opposite direction from how you adjusted your basal.
If you needed to decrease your basal:
It’s most common for basal to be heavy. There are reasons that doctors do this, even if they aren’t completely aware of it. Heavy basal allows for more “free” snacks, makes it so that you don’t have to dose for fat and protein rises, and can, in theory, reduce the number of bolus doses needed.
The reasoning makes sense, but it can be dangerous to have heavy background insulin, especially if you stray from your normal routine. Here are some of the main adjustments you may have to make if you found your basal was too heavy.
“Free” snacks
Often at diagnosis, people are given parameters for “free” snacks. That’s something that you can eat without needing to give insulin.
Some diabetes clinics say that “free” snacks are things like meats, cheeses, and vegetables. Some will tell patients that as long as the snack is under a certain number of carbs, it’s “free”. Often people are told that under 15 grams of carbs is “free”.
I put “free” in quotations, because, for the most part, there are no “free” snacks when it comes to T1D.
There are reasons to have snacks without bolusing. A big one is during the honeymoon phase. Your pancreas is still producing some of its own insulin, so sometimes you don’t have to cover all of your food with an injection. You can get away with having 15 grams of carbs here and there without giving insulin. The main problem with this is that the honeymoon doesn’t last forever, but many doctors neglect to explain to their patients that they can no longer have “free” snacks after the honeymoon phase.
If you’ve corrected your basal rate(s) based on basal testing and you’re not in the honeymoon phase, you’re likely going to have to ditch the idea of “free” snacks.
Bedtime snacks
Bedtime snacks are similar to “free” snacks. During honeymoon, your pancreas is particularly good at lowering bg during the night. That’s because it doesn’t have to fight against food during that time. It gets a bit of a break.
But, especially when you’re also giving insulin manually, low bg during the night can be a scary thought. So, many doctors suggest an uncovered bedtime snack. Eat a complex carb and/or protein before bed and don’t bolus for it. This can be really helpful during honeymoon when your basal and natural insulin are dragging your bg down overnight.
However, now that basal is no longer pulling your bg down, having an uncovered bedtime snack will cause high bg overnight.
Don’t worry, you don’t have to ditch the bedtime snack. You just have to start bolusing for it.
Low treatments
Ah yes, the good old 15-15-15 rule. There are a couple of versions of this rule. It’s a fairly outdated rule and it doesn’t work well for most people if the goal is steady, non-diabetic numbers.
What’s the rule? Well, there are a couple of different versions. When you have a low bg:
- You treat with 15 grams of fast-acting carbs. This would be something like juice, dex tabs, or skittles. Then you wait 15 minutes. Then you recheck bg. If it’s back in range, great. Continue with your day. If it’s still low, treat with another 15 grams of fast-acting carbs and wait another 15 minutes. Repeat as needed.
- This is similar, but instead of finishing when you’re in range, you give another 15 grams of complex carbs or protein to keep bg from dropping again.
15 grams of fast-acting carbs, 15 minutes, 15 grams of complex carbs. 15-15-15 rule.
Now clearly, if you need uncovered complex carbs or protein to keep bg from dropping… something is wrong. As with many of the things on this list, outside of honeymoon, you shouldn’t need to do that.
If you’ve been using these methods to treat lows, but have recently lowered your basal, you might find treating lows with this much will cause your numbers to skyrocket.
The thing is, not all lows are created equal. If you know why a low is happening, it’s a lot easier to determine how much sugar you’ll need to treat it.
But for most people, 15 grams is quite a lot and causes rebound highs.
Dawn Phenomenon and FTF Syndrome
Dawn Phenomenon and FTF (Feet To Floor) syndrome are both natural hormonal fluctuations that can affect bg levels in people with T1D. Unfortunately, neither of them is consistent for most people so they can be difficult to manage.
Dawn Phenomenon (DP) occurs because the body releases hormones to prepare for waking up. Specifically: cortisol, catecholamines, and growth hormones. These hormones, in turn, cause the liver to “dump” glucose into the system. This glucose dump happens around 4am (give or take) and people with T1D often see a rise in blood glucose levels.
FTF syndrome has many names. Feet on the floor syndrome. Feet-to-floor phenomenon. FTF. It’s said many different ways, but it’s all the same thing. Like DP, FTF is a surge of “wake you up hormones” that can cause a rise in blood glucose. But instead of happening in the early morning hours, FTF happens when you physically get up in the morning.
If your basal insulin was previously heavy, it could have been masking one or both of these aspects of T1D management. Once basal is set accurately, you may have to adjust for DP and/or FTF sometimes.
Activity snacks
I’ll tell you right now, I’m not a big fan of activity snacks in general. I really hate feeding insulin, meaning, giving food just because there’s too much insulin on board. Besides, no one likes to exercise after forcing themselves to eat a bunch of carbs.
However, activity snacks are the main solution provided when people ask how to keep bg up during exercise, sports, and other activities. So let’s talk about them.
Just like everything else, your activity snacks may have been partially covering heavy basal. Now that your basal is set correctly, you may find that you need a smaller snack before activities.
Alternatively, if you want to ditch the activity snacks completely, there are ways to do that as well.
The reason that many people see lows during activity is that our bodies become more insulin-sensitive when they’re moving. That means the same insulin that would keep you steady on a non-active day could very well cause lows on an active day.
To avoid activity lows, these are my go-tos:
- Try to start an activity with little to no IOB. If you don’t have active insulin in your system, the increase in insulin sensitivity won’t affect you as much. But do keep in mind that activity can cause insulin sensitivity for 24+ hours after the activity is done.
- Adjust the carb ratio for the meal or snack preceding the activity. This way, you’re still covering the food, but you’re taking the insulin sensitivity change into account.
- Eat low-carb, high-protein foods before activity. This allows you to eat before the activity and also have very little IOB. If timed well, the protein will help maintain bg during the activity as well.
Of course, these options only work if your activity is planned. If you find yourself in a spontaneously active situation, you may still need an activity snack. But since your basal is now set correctly, you may not need as much as you did before.
Fat and protein
Back to the “free” food again. Most people aren’t taught to dose for fat and protein, let alone how to dose for them.
When protein is broken down in our bodies, approximately 50% of it is converted to glucose. This glucose needs insulin just like glucose from carbs needs insulin. Protein breaks down more slowly than carbs and simple sugars, so people who dose for protein will either give an extended bolus on their insulin pump or a second bolus if they’re MDI.
A little bit of fat breaks down into glucose as well, about 10%. The issue with fat isn’t so much that it converts to glucose, but that it causes insulin resistance. So, the fattier the meal, the more insulin you might need (for the same number of carbs).
This is one of the things where people will say that p/f doesn’t affect their bg. But the thing is, the human body doesn’t vary that much. Our diabetes management does. If you’re simultaneously saying that something doesn’t affect your bg and that you’re having trouble figuring out your numbers and how to get off of the T1D roller coaster… well, maybe it affects your bg numbers more than you realized.
Your heavy basal was masking the need to dose for p/f. Now that you’re getting your bg on track, you’re going to have to learn how to dose for p/f.
There are a lot of steps to getting off of the T1D roller coaster
It’s wonderful that you’ve taken the first step! Now that your basal is accurate, you’ll be able to see where other tweaks are needed. Before you know it, you’ll be able to identify the reason for 99% of your highs and lows. Your highs and lows will get less extreme. They’ll be little molehills instead of giant mountains. And eventually, your TIR will be higher than you’ve ever thought possible.
You understand the T1D basics. Let’s get into the advanced levels now. You’ll be more confident. Your A1C will go down and your TIR will go up. With every step, you’re getting closer to non-diabetic bg numbers. It’s not an easy road, but it’s worth it. We can do this!
~ Leah
If you’d like to learn more about basal insulin, there is a lot of information in the book Think Like a Pancreas and the book Sugar Surfing.
For more tips and stories about T1D, join the Carb Counting Mama email list, and make sure to head over to the Carb Counting Mama Facebook page and “like” it.
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