What Is a Personal Baseline?

Everyone's physiology and sleep needs are different. Seven hours of sleep is plenty for some, far too little for others. An HRV of 40 ms may be low for a 25-year-old athlete, yet perfectly normal for a 55-year-old desk worker.

Judging everyone by population averages is like fitting everyone into one shoe size — it simply doesn't work.

A personal baseline is a reference standard built from your own historical data. Mellows continuously learns your sleep patterns and builds a baseline unique to you, covering 12 core metrics — and answers a far more meaningful question: compared to yourself, how did you sleep tonight?

Core Value

• Personalized Scoring — Your HRV baseline is 35 ms and tonight's reading is 38 ms — that's a good state for you, even if the population average is 45 ms.
• Anomaly Detection — When a metric deviates significantly from your normal range (P10–P90), Mellows alerts you proactively.
• Trend Insights — The baseline updates continuously using a 90-day rolling window. After weeks of regular exercise, you can clearly see your HRV trending upward.

Three Stages: 7 → 14 → 30 Days

Your personal baseline matures as data accumulates.

• Initial (7 Days) — Personal weight 35%, population norms 65%.
• Standard (14 Days) — Personal weight rises to 50%.
• Complete (30 Days) — Personal weight rises to 65%, becoming the primary basis for scoring.

From here, the baseline updates daily using the most recent 90-day rolling window.

Why 90 Days?

The baseline doesn't accumulate data indefinitely. An erratic schedule from six months ago shouldn't drag down today's scores. The 90-day window ensures the baseline always reflects who you are now, not who you were.