A joint study by the UK Health Security Agency (UKHSA) and Swedish sleep-tech company Sleep Cycle indicates that passive cough data gathered via a consumer sleep app can act as an early warning signal for respiratory illness across England.
Analysis of three years of anonymised data (January 2023–January 2026) showed that increases in night-time coughing typically occurred around one week before rises in influenza and COVID-19 activity, as measured by PCR positivity and other surveillance indicators.
The cough metrics collected through the Sleep Cycle app, such as total coughs, coughs per user, and coughs per hour of sleep, closely tracked levels of acute respiratory infection reported via NHS 111 calls.
Sleep Cycle is an AI-powered smartphone app that analyses sound during sleep to help users understand and improve their sleep quality. Its cough signal is generated automatically and updated daily, offering a near real-time picture of respiratory illness trends without requiring any action from users.
UKHSA Chief Data Officer Professor Steven Riley said: “These findings suggest that combining established surveillance approaches with novel digital health signals could contribute to an earlier, richer and more resilient understanding of population respiratory health.
“No single surveillance system provides a complete picture of respiratory disease activity, but this shows that passive nocturnal cough monitoring can complement other surveillance systems to provide a timely population-level signal of upcoming disease trends, without being affected by healthcare-seeking behaviour, laboratory turnaround times, backfilling and reporting delays.”
Dr. Emil Carlsson, Research Scientist & Co-lead Author, added: “Equally important, it shows that consumer-generated health data can be transformed into epidemiologically meaningful surveillance signals using rigorous scientific methods while maintaining strong privacy protections.”
