Raw beat-to-beat interval (BBI) messages store the time between heartbeats measured by the optical sensor, with a quality indicator and gaps.
timestampDateTimeMoment the message refers to, in UTC. FIT stores it as seconds since the FIT epoch (December 31, 1989, 00:00:00 UTC); decoders usually expose it as a regular date.
Millisecond part of the timestamp, for sub-second precision.
dataUint16[]Packed values, decoded into time, quality and gap.
Times between consecutive beats, or lengths of the gaps.
qualityUint8[]For each value: 1 for high confidence, 0 for low confidence.
gapUint8[]For each value: 1 when it is a gap (no beat detected), 0 when it is a beat interval.
mesgNumStringGlobal message number identifying the kind of message. Decoders use it to know which profile to apply to the data.