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Glucose Monitoring

Tracking Glucose during Exercise

Continuous Glucose Monitoring (CGM) can help you plan your meals or snacks before exercising. They can also help you spot high and low glucose levels during exercise. Below, we share some tips on how to use CGM during physical activity:

Tips for Sensor Use During Exercise

CGM and fingerstick glucose tests can show different readings during rapid changes in glucose (like during exercise).

  • There can be a 15-30 minute delay between CGM and fingerstick readings during rapid glucose changes (up or down).

When in doubt, check with a fingerstick glucose meter!

  • Especially if you don't trust the CGM number or trend arrow.

Avoid calibrating your CGM during exercise or when your glucose is changing quickly.

  • It's better to calibrate when your glucose level is stable, with flat trend arrows, not after a big meal or exercise.
  • Example: First thing in the morning is a good time to calibrate if needed.
  • Wait about 20-30 minutes after exercise to let the CGM and fingerstick readings match up.


Zaharieva DP, Turksoy K, McGaugh SM, et al. Lag time remains with newer real-time continuous glucose monitoring technology during aerobic exercise in adults living with type 1 diabetes. Diabetes Technol Ther 2019;21(6):313-321, doi:10.1089/dia.2018.0364

Li A, Riddell MC, Potashner D, et al. Time Lag and Accuracy of Continuous Glucose Monitoring During High Intensity Interval Training in Adults with Type 1 Diabetes. Diabetes Technol Ther 2019;21(5):286-294, doi:10.1089/dia.2018.0387

Guillot FH, Jacobs PG, Wilson LM, et al. Accuracy of the Dexcom G6 Glucose Sensor during Aerobic, Resistance, and Interval Exercise in Adults with Type 1 Diabetes. Biosensors (Basel) 2020;10(10), doi:10.3390/bios10100138

Fokkert M, van Dijk PR, Edens MA, et al. Performance of the Eversense versus the Free Style Libre Flash glucose monitor during exercise and normal daily activities in subjects with type 1 diabetes mellitus. BMJ Open Diabetes Res Care 2020;8(1), doi:10.1136/bmjdrc-2020-001193

Da Prato G, Pasquini S, Rinaldi E, et al. Accuracy of CGM Systems During Continuous and Interval Exercise in Adults with Type 1 Diabetes. J Diabetes Sci Technol 2022;16(6):1436-1443, doi:10.1177/19322968211023522