Heart rate variability (HRV) is the variation in milliseconds between consecutive heartbeats. More variation often reflects a nervous system that shifts between stress and recovery. Higher HRV versus your baseline usually means solid adaptation; a sustained drop over one to two weeks points to poor sleep, illness, overtraining, or stacked stress—not one low morning after a hard session.
Scores are personal. Measure at the same time each morning, ideally right after waking. One low day after hard training or a short night is normal; reduce load when the seven-day trend falls and matches worse sleep, higher resting heart rate, or heavier training blocks.
Support HRV with consistent sleep timing, regular aerobic exercise, breathwork, hydration, and less alcohol—it can suppress HRV for 24–48 hours after moderate intake. Treat HRV as one signal alongside resting heart rate, sleep quality, and energy. Ohga Copilot can chart HRV against sleep and training load so you see lagging recovery before you schedule another hard session.
