Fitness trackers check whether you are taking 10,000 steps a day, they measure your heart rate and even keep track of whether you are sleeping well, but they can also predict if a flu is coming.
Much faster than doctors or traditional measuring instruments, they show whether a flu epidemic is imminent in a certain region. Researchers write that in the journal Lancet. They followed 200,000 users of a fitness tracker for two years.
Flu causes a disturbed sleep rhythm and an irregular heartbeat. That is exactly what the researchers could see in the data from the fitness trackers. By combining data from the same region, they saw a flu epidemic arrive in advance. This is useful because it allows the further spread and contamination of the disease to be reduced.
The signs of a heart attack could also be measured with a fitness tracker by irregular heartbeat patterns. It is then important to take stress or other heart-raising conditions into account.