Resting heart rate

Resting heart rate is one of the simplest and longest-established measures a wearable can take. It is usually captured overnight, when the body is least active, and it tends to be stable for a given person from night to night, barring illness, travel, alcohol or unusual physical or mental strain.

A resting heart rate that is a few beats above a person's own recent average is a common early sign that something has changed, whether that is a cold coming on, poor sleep, or a demanding stretch of work. On its own it is a fairly blunt signal, but it is useful in combination with other readings.

Sloane reads resting heart rate as part of the wearable data, and considers meaningful shifts against a person's own baseline rather than in isolation. It is one of several inputs, not a trigger on its own.

As with all wearable data, resting heart rate reflects physiology, not cause. A rise could relate to workload, illness, travel or nothing in particular. Sloane's coaching is careful to suggest rather than diagnose, and to check physiological signals against what is actually happening in a person's calendar and communication pattern.