Fitbit data significantly improved detection of influenza-like illness (ILI) in US patients, according to a study published in The Lancet. Acute infections can cause individuals to have higher-than-normal resting heart rates (RHR), increased sleep duration and frequency, and a decline in activity levels, all of which can be measured using wearable technology. Because an increasing number of people are using personal activity monitors, researchers assessed whether population trends data from one wearable device, Fitbit, may help improve real-time influenza surveillance and limit the potential impact of the disease. The investigators obtained de-identified heart rate and sleep activity data from 200,000...