Power @ 65% HRR
The main aerobic-efficiency trend keeps the full analysed session, but normalizes the workload on VO2 level before converting it back to rowing watts.
HRR = (avg HR - resting HR) / (max HR - resting HR)
workload VO2 = Concept2 watts/body-mass model
VO2 @ 65% HRR = resting VO2 + (workload VO2 - resting VO2) * 0.65 / HRR
Power @ 65% HRR = inverse Concept2 model(VO2 @ 65% HRR)
This is less intensity-biased than scaling watts directly, because the resting metabolic component is handled before the value is converted back to watts.
Heat, sleep, hydration, recovery state, and heart-rate sensor quality can still move the line, so interpret short-term changes cautiously.
VO2max estimate
The blue line uses only steady-state windows after the first 10 minutes, so sprint blocks and early heart-rate lag do not drive the estimate.
Use windows after 10 minutes
Require at least 8 steady minutes
VO2max est = resting VO2 + (steady workload VO2 - resting VO2) / steady HRR
A steady block has low power variability and limited HR drift. Sessions without enough steady data show no VO2max estimate rather than using sprint or unstable data.
Efficiency drift
Drift tracks whether power per heartbeat falls during the usable part of a session. A large negative value can point to fatigue, heat, poor recovery, long pauses, or inconsistent pacing.
drift = slope of 60-second J/beat windows per hour
J/beat detail
Joules per heartbeat remains available in tooltips and the workout detail chart. It is useful within a steady session and between similar sessions, but it is not the best primary trend across different intensities.
J/beat = total work joules / total heartbeats
Eligibility
The aerobic chart uses sessions with at least 20 analysed minutes after warm-up removal, usable watts and heart rate, and enough sample coverage.
Heart rate is shifted 45 seconds earlier relative to power to compensate for cardiac lag. The first 5 minutes are treated as warm-up, and the final 2 minutes are treated conservatively to avoid cooldown distortion.
Required health data
Power @ 65% HRR and VO2max estimate require saved max HR and resting HR on the Profile tab. VO2 estimates also require body mass.
If those values are stale or estimated too aggressively, the normalized power and VO2max estimate will shift with them.