HRV
Heart Rate Variability
Short definition
Heart rate variability — variation in inter-beat intervals.
Full definition
HRV is the variation in RR intervals; high HRV reflects good parasympathetic tone and recovery, low HRV signals stress or overtraining. Used to monitor readiness; common indices RMSSD, SDNN, LF/HF.
Examples
Morning RMSSD 60 — good training readiness.