How Does a Continuous Glucose Monitor Work? And Should You Be Using One?

Written by Krista Bugden
Medically Reviewed by Felicia Newell, RD

August 18, 2023

Sleep trackers, heart rate monitors, fertility trackers, fitness watches…we’ve come a long way in wearable technology since the original 1960s pedometer.

Not only do these wearables offer valuable (real-time) insights that you wouldn’t otherwise know, they offer awareness. Awareness in that they can bring attention to specific behaviors, patterns, or factors that might otherwise go unnoticed in our daily lives..

In the early 2000s, another awareness-raising wearable hit the scene: the continuous glucose monitor (CGM). While originally used for diabetes management, CGM has recently gained popularity outside of the diabetes population. Using a CGM provides real-time data into how your food and lifestyle choices impact your blood sugar. 

Here’s a closer look into how it works…

How Glucose & Insulin Work in Your Body

Glucose is your body’s main source of energy. It comes from the food you eat, especially carbohydrates. When you eat these foods, your body breaks them down into glucose, then these glucose molecules travel through our blood to all the different cells in our body. 

But there's a caveat—cells can't use the glucose on their own. They need help from insulin. Insulin is made in your pancreas and acts like a key to let the glucose into the cells. Once inside, the cells can either use the glucose for energy or store it for later. 

Sometimes your body can have trouble regulating insulin or glucose, resulting in conditions like insulin resistance or diabetes. But by keeping a close eye on your glucose levels—and applying your learnings—can keep this from happening. This is where a continuous glucose monitor (CGM) comes in handy.

How Does a Continuous Glucose Monitor Work?

A CGM uses tiny sensors inserted into the skin that measure your glucose levels 24 hours a day. These sensors send this information to a monitoring device or app that allows you to see your glucose levels in real time. 

CGMs can help diabetic individuals avoid life-threatening complications and manage their condition with ease. A healthy CGM reading is between 70 mg/dL and 180 mg/dL (1). Anything outside of this range may require diabetic individuals to monitor their situation or take immediate action, such as delivering an insulin injection.

For the average individual, CGMs can help us achieve stable energy and moods throughout our day. When our blood sugar is low, we might feel lethargic. When our blood sugar is high, we might feel a jolt of energy or hyperactivity. So it’s best to try to balance our blood sugar levels somewhere in the middle.

If you’re looking for more ways to help manage your blood sugar spike, check out this blog → The 6 Eating Habits "Glucose Goddess" Swears by for Better Blood Sugar

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Good blood sugar balance is also linked with reduced inflammation and associated diseases (2). Dr. David Sinclair, Professor of Genetics at Harvard Medical School and expert in longevity, elaborates on the benefits of tracking your blood sugar levels, “You need a dashboard for your body in the same way you need a dashboard for your car.” 

When individuals use the tools available, he hypothesizes that “what we’ll have is a massive reduction in diseases” (3). In other words, finding strategies that work with your lifestyle and that help regulate your blood sugar levels might just help you lead a longer and healthier life—maybe even decreasing your biological age.

What Can a Continuous Glucose Monitor Tell You?

With the use of a CGM, plenty of lessons can be learned and applied to optimize your health. Here’s what you can do with a CGM and how you can apply it to your life.

1. See How Different Foods Affect You

It’s no secret that certain foods, like candy, can cause your blood sugar levels to spike.  However, other foods can do the same—and potentially fly under the radar—unless you’re tracking your glucose with a CGM.

For instance, coffee creamer, trail mix, bread, store-bought sauces, and salad dressings can contain more sugar than you might be aware of. This can send your blood sugar levels skyrocketing, then crashing back down, leaving you feeling lethargic. 

By wearing a CGM and monitoring glucose responses after consuming certain meals or snacks, you can gain priceless insights into how your body metabolizes different types of carbohydrates and sugar. It can also help to determine how long it takes your blood sugar levels to revert back to normal after a meal. Recording all of this information can help you spot trends and adjust your diet as needed.

2. Determine the Effectiveness of Your Exercise Routine

Typically, blood sugar levels fall during exercise. However, if you’re performing an intense workout, your body may release stress hormones, which elevate blood sugar levels. This could be a sign that you’re pushing yourself too hard (4). A CGM reading can help you gauge where this limit is. From there, you can adjust.

3. Discover How Well You’re Managing Stress.

Your body is naturally equipped to handle short-term stress. Yet chronic stress can lead to heart disease, stroke, diabetes, autoimmune disorders, and mental health conditions like anxiety and depression (5).

When the body is stressed it releases cortisol, a stress hormone. Cortisol raises blood sugar by releasing stored glucose (6). Your CGM will then show elevated glucose levels when compared to normal.

If this becomes a frequent problem, you may need to work on your stress management. Here are a few ideas…

  • Carve out “me time” to relax. Read a book, draw a bath, go on a walk…these are all simple, effective ways to decompress.
  • Focus on getting enough high-quality sleep. (Aim for 7.5 to 8.5 hours.)Taking more time to relax
  • Talk to a friend, family member, or mental health professional.
  • Incorporate stress management techniques like journaling, breathwork, or meditation throughout your day.

Overall, a continuous glucose monitor can lead to more informed, confident decisions regarding your lifestyle and diet. With health data available at your fingertips, you’ll have the nearly psychic ability to see what’s going on beneath the surface in order to optimize your quality of life and overall lifespan.

Krista Bugden
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Krista Bugden

Krista Bugden is a freelance writer with a BS in Human Kinetics from the University of Ottawa. She spent 5 years working as a kinesiologist, giving her the first-hand experience she needed to write well-researched, scientific, and informative blogs.

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    Medical Disclaimer

    This content is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of such advice or treatment from a personal physician. All readers/viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. Neither Dr. Chad Walding nor the publisher of this content takes responsibility for possible health consequences of any person or persons reading or following the information in this educational content. All viewers of this content, especially those taking prescription or over-the-counter medications, should consult their physicians before beginning any nutrition, supplement, or lifestyle program.

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