Cardio RPE and Session RPE

RPE for cardio is usually rated on the Borg 6–20 scale or a modified 0–10 (CR10) scale. The classic 6–20 scale was designed so that multiplying the rating by 10 approximates HR in bpm for a typical person (e.g. RPE 13 ≈ 130 bpm).

The most useful tracking construct is session RPE (sRPE): a single 0–10 rating of the whole session, given ~30 minutes after finishing, multiplied by session duration in minutes to give an arbitrary-units training load:

sRPE load = sRPE (0–10) × duration (min)

Example: a 60-minute run rated 7 → 420 AU. Summing sRPE load across a week gives weekly internal training load, and its week-to-week ratio underpins acute:chronic load monitoring (see training-load-monitoring).

Why log RPE even when you have HR/power:

• It is device-free and captures factors machines miss (illness, heat strain, poor sleep, motivation) — see recovery-monitoring.
• It validates the objective data: an easy-zone HR but RPE 8 means something is off (under-recovery, heat).
• It works across modalities where HR/power are unavailable or unreliable.

• Scales: Borg 6–20 (×10 ≈ HR heuristic) or CR10 0–10.
• Session RPE (sRPE) rated ~30 min post-session on 0–10.
• sRPE load = sRPE × duration (min), in arbitrary units.
• Example: 60 min at sRPE 7 = 420 AU.
• Device-free; captures readiness factors objective sensors miss.

• rpe-rir-logging — the resistance-training counterpart effort scale.
• training-load-monitoring — sRPE load is a primary load input.
• heart-rate-logging — RPE cross-checks HR-based intensity.
• intensity-classification — RPE bands map to intensity categories.
• recovery-monitoring — RPE feeds subjective readiness.