Continuous Glucose Monitors for Athletes: Myth or Real Performance Tool?
Popularized by wearable brands and fitness influencers, continuous glucose monitors (CGMs) are attracting more and more non-diabetic athletes looking to "optimize" their sports nutrition. But what does recent research really say about their actual usefulness for performance?
A popularity that far outpaces the scientific evidence
According to a synthesis published in May 2025 in the Gatorade Sports Science Institute (GSSI) Sports Science Exchange, written by a team led by Dr. Michael C. Riddell, a recognized specialist in exercise and carbohydrate metabolism, CGM use in athletes without diabetes remains largely ahead of the available data. The authors point out that there is still no solid scientific evidence confirming that a higher glucose level during exercise automatically improves performance — a hypothesis nevertheless widely promoted by the marketing of certain devices, including the "glycemic performance zone" concept marketed by a company that has since ceased this activity in 2024.
What glucose data really reveal in healthy athletes
The report highlights a point often ignored: elite endurance athletes naturally present glycemic variations during exercise that differ from sedentary or moderately active people. Some athletes show a drop in glucose at the start of effort (sometimes called "sports hypoglycemia") that does not necessarily harm performance and does not require intervention. In other words, interpreting a CGM reading requires context — and the same numerical value can have different meanings depending on the athlete, the type of exercise and the time of measurement.
Where CGM can still be useful
- For diabetic or pre-diabetic athletes, CGM remains a clinically validated tool for managing glycemia around exercise.
- For endurance athletes doing very long efforts (several hours), CGM can help identify real hypoglycemia episodes that coincide with symptoms, and refine carbohydrate intake strategies.
- For research purposes, CGM provides data to better understand individual glycemic responses to different nutrition protocols.
The bottom line
For the vast majority of non-diabetic athletes, the current evidence does not justify the cost and complexity of a CGM for daily training. A simpler, proven approach remains: adequate carbohydrate intake before and during long sessions, individualized testing, and listening to your body. This article is for general educational purposes and is not a substitute for individualized medical advice.
Helpful products
- Energy gels with electrolytes — a practical, evidence-based way to fuel long endurance sessions without needing a CGM.
Source: GSSI Sports Science Exchange #263 (May 2025)
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