The 30-second version
Each pillar scores 0–100 nightly from real data. The scores are smoothed over time (recent days count more). If your smoothed score stays above your current level long enough, you level up. If it drops below long enough, you level down. The "long enough" gets longer as you climb higher.
The deeper version
Step 1 — Raw scores. Each pillar has 4–6 weighted components. Sleep, for example, is 25% duration vs. target, 20% efficiency, 20% deep sleep %, 15% REM %, and 20% onset consistency. These produce a raw score (0–100) every night. When a data source is missing, the engine reduces confidence in that pillar's score — it doesn't pretend the missing data doesn't matter.
Step 2 — Smoothing. Raw scores feed into an exponentially-weighted moving average (EMA). The most recent day counts most; 3 weeks ago barely registers. Each pillar has its own smoothing rate — Sleep responds quickly (half-life ~4 days), Metabolic Health moves slowly (half-life ~14 days). This prevents one great day from masking a bad week, and one bad day from erasing a great month.
Step 3 — Level changes. Your smoothed score suggests a "target level." If the target is above your current level, a streak counter starts ticking. Once the streak reaches the threshold for your tier, you level up. The thresholds increase with tier:
Foundation (Lv 1–20) ··· 3 days to level up · 5 days to level down
Momentum (Lv 21–40) ··· 5 days up · 7 days down
Discipline (Lv 41–60) ··· 7 days up · 10 days down
Mastery (Lv 61–80) ··· 10 days up · 14 days down
Elite (Lv 81–100) ··· 14 days up · 21 days down
Crossing a tier boundary (e.g., Momentum → Discipline at Level 41) requires an even longer streak — you have to prove you belong in the new tier, not just that you briefly touched the threshold.
Step 4 — XP as resilience. Every day earns XP based on raw score (good days earn more, bad days can lose some). XP decays slowly over time — you can't coast on past performance forever. High XP at your current level acts as a buffer: if your scores dip, the XP absorbs the pressure before you lose a level. Think of it as earned trust — months of good behavior buys you grace during a rough patch.
Step 5 — Cross-pillar effects. Pillars aren't independent. Sustained poor sleep applies a visible debuff to Movement and Mind scores (you can't out-train bad sleep). High performance in both Nutrition and Movement boosts Metabolic Health. When all pillars score 41+, a global Alignment Bonus kicks in. These effects model real physiology — sleep deprivation genuinely impairs exercise performance and emotional regulation.
Step 6 — Character level. The 7 pillar levels are weighted-averaged (Sleep 20%, Movement 18%, Nutrition 18%, Mind 15%, Metabolic 12%, Consistency 10%, Social 7%) into one number: the Character Level. The weights reflect the scientific evidence for each domain's impact on healthspan and all-cause mortality.
// Pillar weights grounded in epidemiological evidence (Cappuccio 2010, Mandsager 2018, Holt-Lunstad 2015). Full rationale: see platform architecture docs.
