Google Research unveiled SensorLM on 28 July 2025 in Mountain View. The foundation model converts raw heart-rate, motion and temperature streams from devices like Fitbit and Pixel Watch into concise text summaries, potentially simplifying clinical reports and everyday fitness and sleep
Key Details
- Trained on 59.7 million hours of de-identified wearable data from 103,643 volunteers across 127 countries.
- Collection window: 1 March–1 May 2024, totalling roughly 2.5 million person-days.
- Signals include optical heart rate, accelerometer, gyroscope and skin temperature.
- Model sizes span 75 million to 1.5 billion parameters.
- A dual pipeline of contrastive learning and generative pre-training automatically paired sensor patterns with text captions.
- Zero-shot tests identified 20 activities without task-specific labels, and few-shot trials reached high accuracy with only five examples.
- Captions outperformed general large language model baselines on coherence metrics.
- Scaling studies followed known scaling laws, showing steady gains as data and compute increased.
- The project brings together teams from Google Research, Google Health and DeepMind.
Background
Wearable trackers have shipped widely since 2013, logging movement, heart rate and sleep. Early systems relied on hand-labeled events, limiting progress. Recent foundation models proved that large-scale multimodal pre-training can bridge modalities such as vision and language. SensorLM adapts these ideas to continuous biometric streams, learning direct links between sensor signals and natural language.
Volunteers consented to share de-identified readings under research agreements that follow global privacy guidelines. The model was evaluated on human activity recognition and on zero-shot classification / few-shot learning / cross-modal retrieval tasks, demonstrating robust generalisation.
Further Reading
The complete methodology and results are detailed in SensorLM: Learning the Language of Wearable Sensors and its downloadable paper.





