Soma Analytics allows you to track a range of metrics on both a mean (average) basis and a minute-on-minute basis:
Mean Metrics:
Reaction Time
Speed
Variation
Accuracy
RCS
RPE
RME
RMF
VAS-F
BPM
rMSSD
SDNN
Time
Duration
Date
Minute-by-Minute Metrics:
Reaction Time
Speed
Variation
Accuracy
RCS
BPM
rMSSD
SDNN