CGM alerts save lives. They also cause alert fatigue when misconfigured — leading users to silence alarms that matter. Here is how to set alerts that are actionable without being overwhelming.
The Alert Fatigue Problem
Studies show that CGM users receive an average of 8-15 alerts per day with default settings. Most people habituate to frequent alarms and begin dismissing them reflexively — including important ones. The goal is fewer, more meaningful alerts.
The Four Core Alerts
- Urgent Low (55 mg/dL): Cannot be turned off on Dexcom or Libre 3. This is appropriate — 55 mg/dL requires immediate action.
- Low Glucose Alert: Default 70 mg/dL. Consider raising to 80 mg/dL if you receive frequent low alerts that turn out to be false alarms.
- High Glucose Alert: Default 200-250 mg/dL. Consider setting to your personal high target (often 180 mg/dL for Type 1, 200 mg/dL for Type 2).
- Signal Loss Alert: Useful but can be annoying when your phone is simply too far from your sensor. Consider a 30-minute delay before triggering.
Dexcom G7 Alert Configuration
G7 → Settings → Alerts: you can set different alert thresholds for day vs. night, different alert sounds, and vibrate-only for daytime high alerts. The Urgent Low cannot be silenced. Customizing nighttime alarms separately reduces daytime interruptions while maintaining safety overnight.
FreeStyle Libre 3 Alert Configuration
LibreLink → Settings → Alarms. Options are less granular than Dexcom. You can set low and high thresholds and choose between sound, vibrate, and silent + notification. Night mode is available.
Advanced: Smart Alerting in xDrip+
xDrip+ allows alert profiles by time of day, alert escalation (repeat if not dismissed), and snooze settings per alert type. Power users can configure: no high alert during 2-4 hours post-meal (expected spike), low alert only from 11pm-7am with a louder sound.
Weekly Alert Review
Monthly, check your CGM app’s alert log. If you received more than 3 high alerts per day on average, consider whether your high threshold is set too low for your current control. If low alerts dominate, discuss basal or bolus adjustments with your care team — alerts are data, not just noise.