Should You Wear a Continuous Glucose Monitor?

April 25, 2024

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We have wearable tech to track our steps, our sleep, our heart rates — and the latest trendy item to have on can help monitor your blood sugar. These devices, known as continuous glucose monitors (CGM), have been around for more than 20 years, and are useful for people with diabetes who need to closely manage their blood sugar. But people without diabetes are using them, too, for a variety of reasons. Is this a good idea, and would it be helpful to you?

What is a continuous glucose monitor?

A CGM is a device that automatically estimates your blood glucose (sugar) levels every few minutes throughout the day and night, and keeps track of it over time. Depending on what model you have, you wear it all the time for 7 to 14 days.

A CGM has three parts:

A tiny sensor, usually inserted under your skin on the arm or belly, with a sticky pad to keep it in place. The sensor estimates the glucose amounts in the fluid between your cells, which is similar to the glucose in your blood.
A transmitter, which sends the data gathered by the sensor wirelessly.
An app, which may be stored on a smartphone, an insulin pump, or a separate device called a receiver. Your data is stored within the app, so you can track your blood sugar over time.

“The blood sugar reading given on the CGM monitor is nearly real time — there’s a 5- to 25-minute lag time behind the actual blood sugar level,” says dietitian and certified diabetes care and education specialist Toby Smithson, co-author of Diabetes Meal Planning and Nutrition for Dummies. “In other words, it’s important to understand that there is a delay in the actual reading, and it is also dependent on how fast the blood sugar level is moving.”

Why are continuous glucose monitors useful?

For people with diabetes, a CGM can make daily management of the disease easier. “I’m one of those people with diabetes who believes the more information I have on my readings, the better I can troubleshoot,” says Smithson, who used to check her blood sugar by poking her finger up to 12 times a day. “So, when we do the math, a 10-day CGM saves me 120 pokes of my finger.”

In addition, for people living with diabetes, Smithson explains that there is a target range for blood sugar levels. The ability to collect the data on the percentage of time blood sugar stays in range has been shown to be a more accurate method for assessing diabetes management than relying on hemoglobin A1C blood test results (which is a measurement of the average blood sugar levels over the past 90 days). For a person living with diabetes, monitoring blood sugar levels is imperative to disease management, as their blood sugar levels fluctuate more than a person without diabetes.

If a person doesn’t have diabetes, but is diagnosed with reactive hypoglycemia, or if they have prediabetes, then wearing a CGM can be beneficial, Smithson notes.

For people without prediabetes or diabetes, CGMs are touted by manufacturers and influencers for a few reasons:

Blood sugar stabilization to help with weight loss
Tracking your body’s response to sleep, exercise, stress, and other lifestyle factors
Managing energy levels
Improving athletic performance

Should someone without diabetes use a CGM to monitor blood sugar levels?

There are some times where a CGM might be beneficial for people who don’t have diabetes, but there are potential drawbacks as well. For people who don’t have diabetes, “It’s normal for blood sugar to fluctuate, especially after eating, but they will not have blood sugars above normal target range,” Smithson says. Because of that, wearing a CGM can be data overload, and may cause needless anxiety, she adds.

After your CGM monitors your blood sugar, it will provide you with nutrition information. Although many of the CGM companies employ registered dietitians to help, the information can be hard to interpret, and it isn’t personalized to you. So although it may help guide you, it’s not the same as working with a dietitian who knows your medical history, habits, food likes and dislikes, and other factors.

Plus, if you don’t have diabetes, your insurance likely won’t cover the cost of the CGM, which can run up to hundreds of dollars per month, depending on the model you use and any membership costs for an app.

There are some potential benefits — though they’re anecdotal at this point, because there aren’t large, long-term studies yet on people without diabetes using continuous glucose monitors. Looking at reviews, users cited benefits such as finding out that certain foods cause more of a spike than they expected, learning how much stress affects blood sugar, and being reminded to combine carbohydrate-rich foods with fiber, protein, and fat to reduce glucose spikes.

How to manage blood sugar without a device

Smithson feels that people without diabetes or risk of diabetes “would be better served by simply focusing on eating a healthy, balanced diet rich with low-glycemic index vegetables, complex carbohydrates, and lean protein, combined with 30 minutes of physical activity most days of the week.”

Since stress and sleep also affect blood sugar levels, maintaining healthy habits around those are key as well.