INTRODUCTION: Continuous glucose monitoring (CGM) has become popular as a supportive tool in diabetic therapy. As CGM devicesmeasure glucose in a minimally invasive manner in the interstitial fluid (ISF) in a frequency of 1 min-1, there is growing interest in theapplication of CGM systems in professional sports and research of glucose kinetics (Holzer et al., 2022). In a diabetic population, a lag-timebetween capillary blood (CB) glucose and ISF glucose was shown (Zaharieva et al., 2019). Therefore, the study’s aim was to compare glucoseconcentrations from CB samples and from CGM measurements in an athletic population.METHODS: Ten healthy athletes (training volume of 10±3 h, 26±4 yrs, 67±11 kg) underwent four tests at rest (R), and two running tests at65% (65) and 85% maximal heart rate (HRmax) (85) following a standardized CHO meal in the evening prior to test morning. Tests wereconducted either in a fasted (FAST) or postprandial state after intake of 1 g glucose / kg bodyweight (GLC). Glucose concentration wasmeasured by CGM device (Abott Libre Sense Glucose Biosensor for Sport, Abbott Laboratories, Chicago, IL, US) using Supersapiens’ Softwarefor crude data access (TT1 Products Inc., Atlanta, GA, US) and CB samples (EKF Biosen C-line, EKF diagnostics Holding, Cardiff, UK).Descriptive data was calculated using Excel 2016 (Microsoft Corp., Redmond, WA, US). Further statistical analysis was performed usingSPSS 28 (IBM SPSS Statistics, Chicago, IL, USA).RESULTS: Pairwise T-test and Wilcoxon-Test analysis reveal a significant difference between CB and ISF glucose concentration for five out ofsix conditions (p<.05). Aggregated mean average relative deviation (MARD) is lowest for R_FAST (7±2%; 11±2%) and highest for 65 and 85(22±14%; 18±11%). Pairwise T-test shows a significant difference in peak glucose concentration (PEAK) between CB and ISF for both R_Glcconditions (183±21 mg/dL vs. 167±20 mg/dL; 180±23 mg/dL vs. 159±17 mg/dL) (p<.05). Wilcoxon-Test for time to peak (TTP) reveals asignificant difference between one out of two R_Glc conditions (27±9 mg/dL vs. 38±8 mg/dL) and for 85 (72±5 mg/dL vs. 43±20 mg/dL)(p<.05).CONCLUSION: The present study shows a delay in ISF compared to CB glucose concentration. Beyond that, results show a higher deviationunder exercising conditions compared to resting conditions. Further data collection especially postprandially and during physical activity isneeded to confirm current findings and to estimate chances of CGM devices’ application in practice and research.
References:Holzer, R., Bloch, W., & Brinkmann, C. (2022). Continuous Glucose Monitoring in Healthy Adults—Possible Applications in Health Care,Wellness, and Sports. Sensors, 22(5), 2030.Zaharieva, D. P., Turksoy, K., McGaugh, S. M., Pooni, R., Vienneau, T., Ly, T., & Riddell, M. C. (2019). Lag Time Remains with Newer Real-Time Continuous Glucose Monitoring Technology During Aerobic Exercise in Adults Living with Type 1 Diabetes. Diabetes Technology &Therapeutics, 21(6), 313–321.