Wearable devices that monitor heart rate, sleep quality, blood pressure and more help people control risk factors for their health. The latest of these tools to go mainstream are continuous glucose monitors, or CGMs.

CGMs were designed to provide precise medication dosing and aid data-driven decisions about diet and lifestyle behaviors to patients with diabetes. Now, CGMs are increasingly worn by people who do not have diabetes but want to stabilize their blood sugar levels, optimize their health and prevent chronic disease.

"A CGM provides real-time insight about how your diet and activities affect your blood sugar levels, even if those levels fall within the normal range," said Ruchi Mathur, MD, an endocrinologist at Cedars-Sinai.

CGMs are medical devices that measure the glucose under the skin (interstitial sugar) to help guide patients in stabilizing their blood sugar levels. Most CGMs measure blood sugar levels every few minutes, 24 hours a day. A sensor sends data to a reader, smartphone or computer that displays the blood sugar levels a few minutes after they’re measured.

CGMs help people with diabetes stay within their target range for blood sugars, which is based on each person’s age and underlying medical conditions. There are normal changes to blood sugars throughout the day, and even people with normal fasting blood sugar levels could have blood sugar spikes and dips. But studies link higher glucose variability to an increased risk of health issues that include heart disease, cancer, Alzheimer’s disease and death, said Roma Gianchandani, MD, a Cedars-Sinai endocrinologist and expert in diabetes technology.

Some CGMs can be worn for only a week, while implantable models last for months. Some transmit data around the clock, while others only provide readings when you scan the receiver over the sensor. All CGMs can stay on during most activities, including swimming, sleeping and eating, Mathur said. Healthcare providers can help determine which device is best for each patient’s unique needs.

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Currently, CGMs are only approved by the Food and Drug Administration (FDA) for people with Type 1 or Type 2 diabetes (and sometimes those with gestational diabetes and prediabetes). “If you are healthy, and don’t have risk factors for diabetes, the deluge of data from a CGM can cause anxiety,” said Natasha Malkani, MD, an endocrinologist at Cedars-Sinai.

But if you have prediabetes, or a concerning medical history, short-term CGM use may help you identify ways to keep your blood sugar levels steady. Here are four ways CGM data can inform lifestyle changes for people who do not yet have diabetes.

• Identify patterns: A CGM allows you to see not only how different foods affect your blood sugar levels when you eat them, but also how these same foods affect you at different times of the day and after different activities. For example, you could find that eating oatmeal within an hour of waking sends your blood sugar levels soaring, but after an hour of gardening, a bowl of oatmeal may keep your blood sugar steady.

“We don’t want people to stop eating fruits and vegetables because of slight blood sugar spikes, particularly since modest rises are expected after eating,” Mathur said. “It’s important to work with a healthcare provider who can help you interpret the data.”

• Refine your workouts: Studies show that exercise can blunt the blood sugar spike that happens after a meal. But a hardcore workout, a marathon training session or even a strenuous hike can flood your body with stress hormones, which can cause blood sugar spikes. Using a CGM can help you understand how your body reacts to different activities.
• Track your stress: When you’re stressed, hormones like cortisol and adrenaline interfere with the body’s ability to break down sugars and carbohydrates, causing blood sugar levels to rise, said Gianchandani. A CGM can help you track how stress affects your blood sugar levels.
• Maximize your sleep: When you’re not getting sufficient sleep, your body is less equipped to use insulin effectively. Lowering your bedtime blood sugar level could help you sleep better and reduce blood sugar variability the following day, provided you don’t dip too low.

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If you’re among the estimated one-third of U.S. adults at risk for diabetes, lifestyle changes are the first line of treatment. That’s where CGMs can be particularly helpful, Gianchandani said. CGMs can help you understand how your body functions during illness, exhaustion, sleep and meditation.

"At Cedars-Sinai, we integrate CGM data into our electronic medical record seamlessly, so we can work with patients to improve their blood sugar levels," she said.

For people who don’t require a CGM for diabetes, CGMs can cost about $1,000 a year. People without diabetes generally only need to wear a CGM for about a month to understand their blood sugar levels. "People who are healthy and don’t have any risk factors for diabetes typically won’t benefit from using a CGM," Malkani said. "Their sugar levels already fall within the normal range with healthy variations from day to day."

If you don’t have a CGM, you can stabilize your blood sugar by controlling meal portions, maintaining a healthy weight, getting sufficient sleep and minimizing daily stressors.

"And see your doctor," Mathur said. "If you have metabolic syndrome, you’re overweight, or you have a family history of diabetes or other risk factors, you may be able to get insurance coverage for short-term use of a CGM to learn more about your blood sugar response to foods and other factors."