Continuous Glucose Monitoring For Athletes: Is CGM Worth It?

Continuous glucose monitoring for athletes has been all over the media as a new, trendy metric that athletes can track for improved athletic performance.

Continuous glucose monitoring involves using a glucose monitor to track your glucose levels throughout the day. There are claims that CGMs can help you perform better, achieve a leaner body composition and boost metabolism.

But are continuous glucose monitors (CGMs) worth your time and money? Can they actually improve your sports performance?

With all of the noise out there, it is important to know the facts. Before buying an expensive monitor and obsessing over ANOTHER set of numbers, let’s get into the facts.

How Does Glucose Control Work?

First, it’s important to have a basic level of knowledge of how glucose works inside your body. 

Glucose is a simple sugar and your body’s primary source of fuel for energy. When you consume carbohydrates they are broken down into glucose (aka: sugar), which then enters your bloodstream. And this will cause your blood sugar levels will rise. A normal, healthy response to increased blood sugar levels is your pancreas releasing a hormone called insulin to help regulate your glucose levels. 

Insulin acts as a key, unlocking cells to allow glucose to enter and be turned into energy. This intricate balance makes sure that glucose remains within a healthy range inside your body. 

Keep in mind that during exercise, there is usually a decrease in insulin levels. This is because glucose is taken up into the muscles through other mechanisms that are independent of insulin.

If your body stops responding properly to insulin, your glucose levels can start to rise and have harmful effects on your body. This is known as insulin resistance and is one of the first signs of prediabetes and diabetes. 

However, for healthy individuals with normal blood sugar levels and regulation, your body knows how and when to release insulin to make sure glucose levels are under control. 

What is a Continuous Glucose Monitor (CGM)?

Diabetics (both type 1 and type 2) and prediabetics need to be able to consistently track their glucose levels so that they can regulate with supplementary insulin dosages. 

A continuous glucose monitor (CGM) was invented as an easy way for people to track their glucose levels throughout the day. 

By wearing a small sensor under your skin, CGM devices measure glucose levels in your interstitial fluid. Next, the sensor sends this information to a receiver or phone app, displaying your real-time glucose readings and trends.

CGM alerts can notify you when you have low or high glucose levels, allowing for immediate action to prevent any complications before they take place.

As you can imagine, for someone with diabetes, this tool can be very valuable. But what about perfectly healthy individuals? Why would they want to use a CGM?

Well, CGMs have been rising in popularity among athletes, especially endurance athletes. There have been plenty of companies and well-known athletes that swear by glucose monitors. But, does the medical community and sports dietitians think it’s worth the hype?

What is Continuous Glucose Monitoring for Athletes?

CGMs made their way into the athletic community as a potential way to improve athletic performance. It is thought that by knowing your blood sugar levels, you will be able to assess how well you are fueling and utilizing that fuel while training. 

Brands such as Supersapiens and Abbott target athletes to sell specialty-made CGMs that can be worn during training and races. They claim the monitors can help you boost your metabolism and optimize your nutrition through glucose stability. 

The question lies, is there scientific evidence to back up these claims? And the answer is, not really.

There are a couple of studies (1,2,3) conducted on the use of continuous glucose monitors in athletes. It is important to note that these studies done are small in size. 

The findings of these studies found that, for the most part, each athlete’s glucose levels stayed within a normal range throughout the tests and higher or lower levels didn’t correlate with performance. 

This means that even if you are using a CGM, your high or low levels may not have anything to do with your training or what you are eating.

Will Continuous Glucose Monitoring Improve My Performance?

After looking at the available research, and learning about how glucose control works in the body, it is likely to say that using CGMs won’t inherently improve your performance.

In fact, I believe that the use of continuous glucose monitors in athletes could lead to obsessive tendencies and the fear of insulin. Many athletes are associating insulin resistance and high blood sugar levels with weight gain and contributing to body fat. But this isn’t the case!

Your body needs carbs for fuel. When you eat carbs as an endurance athlete, you are more likely to have a minimal insulin response because your body utilizes the carbs as energy right away. This is especially seen in cyclists and ultraendurance athletes. 

So, a device like a CGM isn’t really all that helpful for everyday, healthy people. You can’t change how your body reacts to glucose anyways, so continuous readings appear to be an unnecessary metric to track, with little to no performance benefits.

If you are looking for practical help with how to fuel for performance, make sure to check out my downloadable fueling guides! They can help you gain clarity and understanding of how to best fuel before, during, and after your workouts.

Personal Considerations for Athlete-Specific Needs

There are specific considerations for when a continuous glucose monitor may be useful in athletes. The two most prominent are athletes who already have diabetes or prediabetes. 

In these two populations, glucose fluctuations hold more importance and insulin may need to be administrated. If you suspect that you have diabetes or prediabetes, it is important to talk with your healthcare team. They will get you a proper diagnosis and treatment protocol. 

Besides the diabetic population, there is little evidence for the beneficial use of CGMs in other general healthy populations at this time.

Continuous Glucose Monitoring for Athletes: The Takeaway

All in all, continuous glucose monitoring for athletes doesn’t currently have the literature to back up its claims. Until more research is conducted, I would hold off before jumping on the CGM train. 

You are better off saving your time and energy, and instead focusing on foundational fueling strategies such as meal prepping and eating enough protein. Save the money you’d spend on a CGM and buy yourself a new pair of running shoes!

Tired of hearing all of the noise around endurance fueling? Get clarity by working with a sports dietitian, my specialized team here at ALN is here to create a personalized plan to maximize your sports performance. 

Like cyclist Brent, who said this after 90 days in our 1:1 program:

“I have the confidence to be in control of my fueling and health. My sleep has improved, my stress has improved, my mood has improved and now I’m feeling like I can achieve goals that I never thought possible. I can honestly say that I feel like I did 15 years ago.” -Brent

If you are ready to start hitting PRs while feeling better than ever, you came to the right place! Click here to apply today and secure your spot!