Fitness Analytics Glossary

Plain-English definitions of every metric Fitiv tracks — HRV, VO2 max, training load, recovery, and more.

F

FTP (Functional Threshold Power)

FTP is the highest average power output a cyclist can sustain for approximately one hour. It is the central benchmark for all power-based cycling training zones.

H

HRV (Heart Rate Variability)

HRV is the variation in time between consecutive heartbeats, measured in milliseconds. It is the primary metric used to assess autonomic nervous system recovery status.

R

Resting Heart Rate (RHR)

Resting heart rate (RHR) is the number of heartbeats per minute at complete rest. It is a reliable indicator of cardiovascular fitness and a daily recovery marker.

Running Power

Running power measures the mechanical work rate of running in watts, enabling intensity-based training that is immune to the effects of terrain, wind, and heart rate lag.

T

Training Readiness

Training readiness is a composite score combining HRV, resting heart rate, and sleep quality to indicate whether your body is prepared to handle intense training on a given day.

TRIMP (Training Impulse)

TRIMP (Training Impulse) is a heart rate–based training load metric that quantifies workout stress from HR intensity and duration, used across all HR-monitored sports.

TSS (Training Stress Score)

TSS (Training Stress Score) quantifies the physiological stress of a cycling workout relative to FTP. It combines workout intensity and duration into a single load number.

V

VO2 Max

VO2 max is the maximum rate of oxygen consumption during intense exercise, expressed in mL/kg/min. It is the gold-standard measure of aerobic fitness and endurance potential.

Z

Zone 2 (Aerobic Training Zone)

Zone 2 is the aerobic training zone at 60–70% of maximum heart rate. It is the primary stimulus for mitochondrial development and endurance base building.