Can Continuous Glucose Monitoring Improve Your Fitness?

CGM devices work by using a tiny sensor inserted just under the skin to measure glucose. The reading is transmitted to a receiver, smartphone or smartwatch, which then displays the data at regular intervals. 

Traditionally prescribed to help people with diabetes, CGM systems are now available over the counter and are gaining popularity among individuals without diabetes seeking weight loss, enhanced sports performance, better sleep, reduced stress and overall wellness. 

While these devices can offer insights into how diet and lifestyle affect blood sugar, research on their effectiveness for individuals without diabetes, prediabetes or insulin resistance is limited.  

For general wellness, consulting with a physician or certified health educator about using CGM can ensure its use aligns with your health goals, says Athena Philis-Tsimikas, MD, corporate vice president of Scripps Whittier Diabetes Institute and an endocrinologist at Scripps Clinic. 

“There is excellent data on beneficial effects on glucose lowering, preventing dangerously low blood sugars and even reducing medications through positive behavioral changes for people with insulin-requiring diabetes using CGM systems,” she says.  

“In recent studies, we have even seen weight loss and better glucose for individuals with non-insulin requiring diabetes. Although CGM has great potential for health benefits, there is limited research demonstrating concrete outcomes in those without diabetes for now,” she says. 

Dr. Philis-Tsimikas emphasizes that glucose patterns differ widely from person to person. 

“Blood sugar excursions (or rises and falls) are dependent on a lot of things that you do — what you’re eating, how you’re exercising and your genetic makeup because some people are going to be more resistant to insulin than others. It’s very individualized,” she adds.  

“You’re monitoring moment-to-moment changes based on what you’re eating, but if you’re eating something with higher carbohydrates, one person’s body may bring their blood sugar down right away and another person’s may take longer. There’s a huge amount of variation.” 

Annabelle Sanchez, a registered dietitian and diabetes care and education specialist at Scripps Whittier Diabetes Institute, says that when combined with other data, like from a wearable fitness tracker, CGM could spur healthy lifestyle changes. However, she points out there are a lot of variables when it comes to blood sugar levels. It’s important to work with a health care team to interpret the data and get a more holistic picture of your overall health. 

“By providing real-time, personalized feedback on how food choices impact blood sugars, an individual can then modify their nutrition and exercise habits to keep blood sugars in a normal range,” she says. 

“Ideally, when someone starts using a CGM sensor, they have either had a conversation with their provider or are planning on having a conversation with their provider about the glucose tracking because their physician acts as a co-pilot who’s there for them and can put it in perspective,” she continues. “That’s really the best way to use this device.” 

Dr. Philis-Tsimikas adds that while the devices can provide a look into how a person’s body reacts to glucose, they are not intended to be a self-diagnostic tool. If rises in glucose above normal values are noted, then follow up tests may be needed. 

“One-third of all people with diabetes in the US are not diagnosed at this point in time,” she explains. “I could see how this could be useful if someone sees high numbers, then goes to their doctor and says, ‘What does this mean?’” 

CGM data may lead to self-referral and early intervention, Sanchez says. 

“There are a lot of people who have prediabetes and diabetes and do not know it because they don’t routinely go to the doctor,” she emphasizes. “So, when they wear it and start getting some numbers that are quite high, it’s a good thing they’re connecting with a provider who can screen them.”