Our heartbeats differ just enough to tell us apart, but they also give away potentially sensitive information.
Heartbeats, like our fingerprints and faces, are unique. The distinctive waveforms generated by a heart’s expansions and contractions differ just enough from person to person that they can be used to tell us apart. That means heartbeats could serve as a biometric — a unique physiological characteristic that can be used to identify a person. Some scientists think a heartbeat could be a better identifier than the fingerprints we use to unlock phones today.