• Ariel Warren, RDN, CDCES

Why Extending Sleep Activity with Control-IQ May Worsen Blood Sugar Swings

The purpose of this post is to explain why using sleep activity all day with Control IQ can be more harmful than helpful as you try to increase time, decrease swings, and lower your A1c.

In a recent Youtube video, I talked about my review of Control-IQ through my early access as an educator. During this video, I mentioned potential benefit of extending sleep activity past the times when you are actually sleeping. My recommendation was given only if you are working with your provider in order to keep you safe.

However, I would only (maybe) recommend trying extended sleep activity for someone who eats a lower carb (typically high fat) diet and who has very little variability in blood sugar. Most of us type 1s, are people who like to eat foods other than meat and veggies all day, everyday. We exercise and we have hobbies. So increased variability in blood sugar (AKA blood sugar swings) are bound to happen. You may ask, "so why not go with the Sleep Activity mode for a tighter range?"

First, understand that sleep activity calls for a narrowing range for your blood sugar target after about 5 hours of use (so don’t be flipping in and out of sleep activity). The range is gradually tightened to better keep your blood sugar between 112.5 - 120 mg/dL. Which is an exceptionally tight range. Exactly 7.5 mg/dL to be precise.

Sheesh! With the 0.5 mg/dL difference here . . .

So why not be in sleep activity . . . all day??

The big question.

When sleep activity is activated, the treatment values are lower and narrower since there are fewer variables involved. Variables such as exercise and food, and normal life (chasing your kids around, mopping the floor, grocery shopping, etc). Such factors are not at play during sleep, which allows for the less aggressive nature in correction of severe swings and a much tighter range during CIQ's Sleep Activity. At least I sure hope you aren't sleep eating, that would be quite problematic if you have diabetes.

How sleep activity works is that when your blood sugar is predicted to be less or equal to 112.5 mg/dL, Control-IQ will start to decrease your basal and will completely stop if your blood sugar is predicted to go at or below 70 mg/dL 30 minutes in the future.

On the flip-side, if Control-IQ predicts that your blood sugar will go at or above 120 mg/dL, your basal will be increased. However, during sleep activity, Control-IQ doesn't deliver an automatic correction bolus. The automated correction bolus delivers 60% of your usual correction with your target blood sugar set at 110 mg/dL, and is reset every 60 minutes.

Control-IQ (without Activities) Adjustments . . .

The ISSUE is that sleep activity doesn’t allow for dynamic changes in blood sugar because of how tight the range is (112.5 - 120 mg/dL)

Sleep Activity Basal Adjustments . . .

The tight range during Sleep Activity doesn’t allow for the more aggressive nature of regular activity to keep you from those swings. Having a larger range, more algorithmic steps, and auto corrections allows for Control-IQ to better mitigate the swings while increasing your overall time in range (70- 180 mg/dL). The sleep activity algorithm is to keep you in a tighter range during a time with less swings in your blood sugar profile. You know, like when you’re sleeping . . .

As stated before, there are some who may be able to get away with extending their sleep activity if they have little variation in their blood sugar. Typically, these are people who are eating very low carb and high fat. However, that’s not the case for most

because we are people. We like to eat outside the ultra low carb restrictions. We like an occasional treat or some popcorn while watching a movie. We have things to do, people to see, and places to go!

So How Am I Supposed to Achieve a Lower Average with Control-IQ?

I'm glad you asked.

What you CAN do is slightly increase your basal to aim for the lower end of the 112.5 - 160 mg/dL range. HOWEVER, 112.5 mg/dL is the lowest you can aim to prevent rebound (and stubborn) postprandial highs. Postprandial, just a fancy term meant for after dinner.

Let me explain.

The Issues if you Overbasalize

If you increase your basal TOO much, you run the risk of a basal that is often decreased or suspended because your Control-IQ predicts your blood sugar dropping below 112.5 mg/dL threshold. If your basal has been decreased or worse, suspended before a meal, you are going to have decreased coverage going into the meal. Decreased basal causes for insufficient insulin going into your meal which will then cause your postprandial blood sugar to rise quickly, higher, and be more stubborn to bring back to target range.

If you just hate the idea of hovering around 112.5 mg/dL, you COULD slightly increase your basal a bit more (yes, I understand "a bit" is very vague), which will likely cause for intermittently decreased and suspended basal. You then would need to bolus for extra carbs and bolus further in advanced before a meal.

However, at this point, we are playing with fire and all the mind games can make good and consistent control rather difficult. Which then defeats the purpose of this pump anyways, right?

Yes, there are always work-arounds, but you need to stick with what is sustainable to keep yourself from a burn out. It is better to have decent, but consistent control through the years, compared to periods of "fully-functioning-pancreas" status mixed with periods of rebelling "my-pancreas-is-broken-but-I'm-invincible" teenager status.

If a system is NOT working the way you need it to for your desired level of care, you need to work with an educator and find a system that will get you where you want to be without the mind games. With today's tech, you have a lot of options with educators (local or through telehealth) and with your management (other closed loop systems, shots, pens, different types of insulin). You also need to consider what your insurance will pay for, so check before get your heart set.

T-Slim X2 is a Great Pump

People have had fantastic results with this pump and have been very happy. Recently, I had a had patient tell me that they have seen as much as a 2.0% drop in A1c after only 20 days of using Control-IQ without increased work?!?

The T-Slim X2 by Tandem is a solid pump (for 95% of the population). Only if you are, as I affectionately call them, the crazy-heads who like to keep their A1c consistently in the lows 6s and the 5s. I am a crayz-head myself. These crazy-heads may achieve their desired level of care with a system such as OpenAPS looping. I have been looping for about 10 months and have enjoyed the majority of my looping days. My looping experience will be for another day and another post, but I am a fan. At least for the crazy-head population who desire very tight management.

I have a Tandem pump, and used it for Control-IQ, but I then went back to OpenAPS looping. I like to try each of the systems and new tech developments so I can be a better resource and educator for my patients.

How to get Great, Lasting Diabetes Control

It is all about having good settings and understanding how environmental and physiological factors affect your control. Much easier said than done. Factors such as nutrition, exercise, sleep, the timing of meals and sticking to foods that specifically work well for YOU. Also, relating to food, understanding how it's NOT just about carbs, but how to account for protein, and fat and the different types of protein and fat (such as plant based vs animal based). Also, with the type, consistency, timing, and intensity of workouts. Then there is the affects of good (or poor) sleep. You need to understand how the amount, quality, and variability of your sleep affects insulin sensitivity/resistance.

These factors are the big ones, but there are many (and highly individualized) factors that also affect your control. This isn't meant to be discouraging, but exciting! Because if you can pinpoint the reason for your "uncontrollable" blood sugar swings, then often times, the reason can be addressed, and you can normalize your blood sugar.

Sleep Activity Takeaway . . .

Sleep activity all day doesn’t allow aggressive suspension and auto corrections to better keep you in range and with less swings. To decrease overall blood sugar, review your reports (on Tconnect) to identify trends, and perhaps work with an educator to gradually increase basal to aim for the lower end of the 112.5 - 160 mg/dL range targeted with Control-IQ. Too much basal, can cause for decreased or suspended basal into a meal, which reduces overall coverage, which then can cause rebound highs which are higher and more stubborn to treat compared to usual postprandial spikes. There are always work-arounds, but too many can burn you out, so you need to find a provider and a management method that works for you. Sustainability is key. Lastly, 99.9% of "unpredictable blood sugar" can be explained which is wonderful news! Because if we can pinpoint why your blood sugar is being unruly, often times we can correct the environmental factor for easier and lasting diabetes control.

Finally, I have some big news that I’m super excited to share . . .

My book, "Type 1 Diabetes for the Newly Diagnosed " has just been released and in this picture, I’m holding the first physical copy. This book is to help people with T1D who are newly diagnosed, but it's a great resource for anyone who has or wants to better understand T1D. There are 14 chapters total that go through what to expect, what to do, and how to thrive with diabetes (honeymoon phase, exercise, nutrition, carb counting, the emotional tolls, having kids, diabetes and alcohol, etc). Also, each chapter is introduced with a real story from real people who also have T1D.

I was contacted by a publisher awhile back to write this book. I was excited, but quite overwhelmed, but knew I had to do this. I absolutely love working with people to improve their diabetes and get their life back. I have had diabetes for over 25 years and have 2 healthy kids without complications. In a odd way, I'm grateful for my diabetes because it has given me a deep level of empathy for those who haven't had life easy. It also allows me to connect with my patients because I understand on a very personal level, what they are going through.

Lastly, there are two overarching themes throughout this book. First being that the goal with diabetes is NEVER perfection, but progression. The second is that you are never alone with your T1D. You have your friends and family, but with today's tech and the internet, you also have access to so many great educators, along with other people with T1D through online communities and support groups.

As always, if you are struggling with your diabetes (newly diagnosed or a long-time veteran). Perhaps you need pump adjustments, insight on how your nutrition is affecting your insulin sensitivity, you want to understand how to go about making your own insulin changes, you are suffering from poor absorption, or maybe you just what to work with a healthcare provider who understands diabetes on a personal level. Do not hesitate to write me an email or schedule with me for a consultation. I'm here to help and I love helping people with diabetes increase their control and quality of life.


Ariel Warren, RDN, CD, CDCES

UT-ADCES Chair-Elect

Diabetes Care & Education Specialist

Type 1 Diabetes for the Newly Diagnosed