Garmin Index Sleep Monitor S/M Black

The Garmin Index Sleep Monitor S/M is a lightweight upper-arm sensor designed for overnight physiological tracking. It uses an optical measuring system to record sleep stages, heart rate, heart rate variability, respiratory rate, skin temperature, and blood oxygen saturation. Data transfers over Bluetooth Low Energy directly to the Garmin Connect app. A rechargeable lithium-ion battery provides up to 168 hours of use per charge. The sensor does not use a chest strap, relying entirely on the armband format for continuous data collection.

The adjustable band fits arm circumferences between 20 and 29 cm. A plastic housing encloses the internal components while keeping the unit light. Synchronisation occurs with both iPhone and Android smartphones, alongside compatible Garmin smartwatches for unified data review. The sensor estimates caloric expenditure based on heart rate data. It also tracks Body Battery energy levels and stress metrics to provide a broader view of overnight recovery.

• Weighs 14.5 g for unobtrusive wear.
• Waterproof up to 5 m for resilience in wet conditions.
• Bluetooth 5.0 protocol for stable wireless connectivity.
• Band material comprises 70% nylon and 30% elastane.
• Includes a USB charging and data cable.