Effects on glucose levels after running long-distance races

BACKGROUND: Glucose serves as the body’s primary energy source, crucial for sustaining functional muscle levels during high-intensity physical activity. Its regulation is influenced by various factors including exercise intensity, frequency, duration, and insulin levels. To assess interstitial glucose concentration and glycemic variability in ultramarathon runners participating in a 50-km ultramarathon event.METHODS: In this cross-sectional study, we evaluated interstitial glucose concentration and glycemic variability in endurance runners during and after an ultramarathon race.RESULTS: We observed statistically significant differences in average glucose levels between the race and postrace periods (114.9±17.8 vs. 94.7±18.53 mg/dL; P=0.001), with a mean glycemic variability of 16.2±2.7%. Notably, some runners did not adhere to the recommended monitoring frequency (at least every 8 h) for interstitial glucose levels during and after the race. Analysis of continuous glucose monitoring (CGM) metadata revealed that nine participants experienced low glucose events postrun (levels equal to or below 69 mg/dL).CONCLUSIONS: Optimal glucose levels play vital roles in recovery and metabolic adaptation. These findings emphasize the importance of monitoring and managing glucose levels in ultramarathon runners to support their performance and overall health.