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Are you living with Type 1 Diabetes or have a child with t1d, and feeling anxious every time you check your CGM and see those dreaded up and down arrows? If you’ve found yourself overly focused on those up and down trend arrows and finding it hard to actually stay in range for longer than an hour, read on. Let's dive into why focusing on CGM arrows might be messing with your blood sugar management—and how you can regain control with a simpler, more effective strategy.
Why CGM Arrows Can Be Misleading for Type 1 Diabetics
Continuous Glucose Monitors (CGMs) are an amazing tool for managing Type 1 Diabetes, but there’s a big problem with relying on CGM trend arrows. These arrows—pointing up, down, or straight across (or double up, double down etc.) —can create confusion, anxiety, and ultimately lead to incorrect insulin decisions. Let me explain why these arrows can’t always be trusted and how they can mess with your blood sugar management.
Understanding CGM Arrows and Their Limitations
When using a CGM, you’re often looking at trend arrows to determine how your blood sugar is behaving. While this may seem like an easy way to make decisions, there are several reasons why CGM arrows can be misleading:
Lag Time in Data: CGMs, like the Freestyle Libre and Dexcom, aren’t real-time devices. They can be up to 15 to 30 minutes behind your actual blood sugar levels. This lag means you could be seeing data that’s not entirely reflective of your current glucose status.
External Factors Affect CGM Accuracy: When you’re exercising, experiencing stress, or exposed to extreme temperatures, your blood sugar can fluctuate rapidly, but CGMs may struggle to keep up. This can result in inaccurate readings or predictions.
Inconsistent Arrows: CGM arrows are meant to show trends—up, down, or steady—but they lack nuance. A double-up arrow, for instance, doesn’t take into account how much your blood sugar is rising or how quickly it’s happening.
Why Relying on CGM Arrows Might Cause Anxiety
For many people with Type 1 Diabetes (or parents of), seeing a “double-up” or “double-down” arrow can trigger panic. This anxiety often leads to incorrect decisions, like over-treating lows or unnecessarily adjusting insulin doses. But by focusing too much on arrows, you’re making decisions based on outdated data that doesn’t reflect the full picture of your glucose trends.
The Better Approach: Focus on the Tail of Your CGM Graph
The only way you can actually see what your blood sugar is doing is to 1. learn to read your graphs properly (assuming your CGM is reading accurately in the first place.)
Instead of fixating on the arrows, I recommend a much simpler strategy for better blood sugar management: look at the tail of your graph.
What is the "Tail" of Your CGM Graph?
The tail refers to the most recent part of the graph—the last few minutes or hours—where you can see the direction your blood sugar is headed. It’s a much more reliable way to make informed decisions than simply reacting to an arrow.
How to Use the Tail for Better Blood Sugar Control:
Check the Graph’s Trajectory: Is the tail of your graph showing an upward, downward, or steady trend? This gives you more insight into how your blood sugar is changing and allows you to make adjustments accordingly.
Use This Data to Adjust Insulin or Carbs: If your tail shows an upward trend with a relatively stable blood sugar number, you might need to consider reducing your insulin or adjusting your carb intake.
Avoid Panicking Over Arrows: Stop focusing on the arrows themselves. Instead, by assessing the tail, you can create a more accurate plan based on your body’s true glucose changes.
How This Strategy Works: Real-Life Examples
Example 1: Low Blood Sugar Trends
If your blood sugar is 5.2 mmol/L (75mg/dl) and the tail of your graph shows a slight downward trajectory, this is indicating your blood sugar has dropped over the last 30 minutes (but not necessarily 'quickly'.) It might be a good time to take in some glucose or back off insulin for a while. If on the other hand, you see the line of the graph has plummetted (straight down) in the last 30 minutes, this indicates your blood sugar has dropped quickly and you should act as if you're at risk of a hypo - even if you aren't 'low' yet.
Example 2: High Blood Sugar Trends
If your blood sugar is 15 mmol/L (270mg/dl) but the tail is still climbing, you’ll want to prepare for further increases. You can adjust your insulin dosage accordingly, rather than relying on an arrow that might actually show 'straight across'. Visually you can see that the line is on the way up, so trust this over the arrow.
This strategy, while simple, helps eliminate the confusion and frustration often tied to CGM arrows, empowering you to make better, more confident decisions (and lessen anxiety).
Why You Should Stop Relying on CGM Arrows
By disregarding trend arrows and focusing on the tail of the graph, you can:
Reduce anxiety and make decisions based on more reliable data.
Minimize overcorrection by making smaller, more accurate adjustments.
Stop eating unnecessary hypo treatments: which can impact your dental health and long term weight and health.
Improve overall blood sugar management by embracing a more intuitive method.
Additional Tips for Better Type 1 Diabetes Management Using a CGM
Managing Type 1 Diabetes requires a holistic approach. In addition to tracking your blood glucose levels, it’s important to take into account other factors such as:
Nutrition: How you eat impacts your blood sugar control.
Exercise: Physical activity affects glucose levels.
Sleep: Rest is crucial for managing blood sugar levels effectively.
So I hope you can now see how by focusing on the tail of your CGM graph, you’ll start to make better, more informed decisions that lead to more consistent blood sugar management. If you’re looking for more tools and strategies, don’t forget to check out the resources below, and if you haven't already, listen to the podcast episode I shared on this topic.
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My 1on1 coaching sessions are designed to help you learn the fundamentals of good blood sugar management, including learning how to dose accurately based on your needs. Together, we can work on dialling in your blood sugar levels around meals, exercise, hormonal cycles and more - to help you feel more in control and confident in your daily life with Type1.
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