In the first days the band is not just counting — it is learning. To say “your sleep is better than usual” or “worth easing off today”, it needs to know what “usual” means for you. That is calibration: collecting your personal baselines.

What works right away

Sleep. Stages, duration, the score for the night — all counted from the very first night. There is nothing to compare against here, and no need: seven hours of sleep is seven hours of sleep.

Steps, heart rate, workouts and stress are visible from day one too. Calibration switches nothing off — it makes the assessments more precise.

What is collected over the week

Load baseline — 3 days. The band looks at how much you usually move, and from then on compares a day not with an abstract number but with your own level.

HRV baseline — 4 nights. Heart rate variability differs from person to person: 30 ms for one, 90 for another — and both are healthy. Until there is a personal base, recovery is calculated with a simplified formula; with the base it becomes yours.

Resting heart rate baseline — 7 nights. The longest base and the most valuable: resting heart rate is a quiet indicator of fitness, and its baseline must be precise enough to notice a shift of even a couple of beats.

Progress on all three is visible on the summary — in the “Band is calibrating” card. As soon as the last baseline is collected, the card disappears.

Why it cannot be faster

HRV jumps from day to day — after a workout, a late dinner or a short night. One night says nothing about a baseline, just as one coin toss says nothing about whether the coin is fair. Several nights is the minimum for your middle to emerge. Every serious tracker works this way: the first days are learning.

How to help the band

  • Sleep in the band every night: a night without it does not count towards the baselines.
  • Wear it snugly, a finger above the wrist bone: the sensor needs contact with skin. If the band is loose, HRV may not be recorded overnight.
  • Charge it during the day, not at night. Twenty minutes on the charger while you shower is usually enough.

What changes afterwards

The calibration card leaves the summary, and recovery, load and sleep start being counted from your personal baselines. From then on the word “baseline” in the app means “baseline for you” — not an average across all people.