Heart Rate Variability (HRV) might be the most accessible—and powerful—predictor of cardiovascular and nervous system health that you are probably not measuring. Today’s letter is dedicated to ...

Heart rate variability (HRV) is the variation in time intervals between consecutive heartbeats, typically measured in milliseconds. A healthy heart does not beat with metronomic regularity — the ...

Watches measure more than just heart rate. If you list blood oxygen, skin temperature, ECG, respiration, body composition, ...

Can a wearable detect rising stress and change what a patient hears? An Indian system uses heart-rate variability to adapt ...