Continuous glucose monitors have moved beyond diabetes management into the fitness and biohacking space, with athletes using real-time glucose data to optimize fueling strategies and understand metabolic responses to different exercise types. We tested five consumer-available CGM devices during structured workouts including steady-state running, cycling intervals, heavy weightlifting sessions, and HIIT classes. Accuracy was validated against concurrent fingerstick measurements using a Contour Next One meter. The Abbott FreeStyle Libre 3 provided the best overall accuracy during exercise with a mean absolute relative difference (MARD) of 8.2% across all activity types. The Dexcom G7 excelled with its rapid update rate and reliable trend arrows during intense intervals. The newer Levels CGM impressed with its app that contextualizes glucose responses to specific workouts, though it uses the Libre sensor underneath. We also tested the Signos and Nutrisense platforms for their fitness-focused analytics.
Best Continuous Glucose Monitors for Fitness in 2026: 5 CGMs Tested During Workouts
