Science
based.
Every number in the app comes from a published formula, a study cohort or an official database. Here they are, engine by engine.
Four physiological pillars, combined every morning
Your readiness score combines four pillars: your overnight vitals (heart rate variability, resting heart rate, breathing), your sleep (duration against your need, stages, efficiency, regularity), your nutrition (how well you hit your targets, protein after training, micronutrients, hydration) and your rhythm, including your recent training load — a hard session is paid for over 24 to 72 hours.
The key point: your vitals are never compared with a population norm. Each one is assessed against your own baseline, built on your last six weeks of data. An HRV of 45 ms can be excellent for you and poor for someone else — the score knows it.
Read the details →Anchored on your VO₂max, backed by the HUNT cohort
Your biological age starts from the marker research links most strongly to longevity: cardiorespiratory fitness (VO₂max). Converting it into years relies on work from the HUNT cohort — the benchmark Norwegian study and one of the largest databases of measured cardiorespiratory fitness in the world — and it is then refined by modifiers drawn from your actual habits: heart rate variability, sleep, activity, waist circumference, diet.
Your running performances go through Jack Daniels' VDOT formula, the endurance-training standard for forty years. And the calculation runs from day one: no need for a month of history to get a first honest answer.
HUNT cohort (Nord-Trøndelag Health Study, Norway) — VO₂max norms by age and sex.
Jack Daniels & Jimmy Gilbert — VDOT tables, Oxygen Power.
400,000 foods from official databases
When you scan a meal, the analysis does not come out of nowhere: each food is matched against the reference public nutrition databases — the ANSES Ciqual table (France's food safety agency: 3,484 foods, 257,000 nutrient values measured in the lab), USDA FoodData Central (more than 400,000 US entries) and Open Food Facts for barcoded products.
Macros, micronutrients, antioxidants: every value shown in the app can be traced back to its official source.
ANSES — Ciqual food composition table.
U.S. Department of Agriculture — FoodData Central.
Your baseline, not someone else's
Heart rate variability and resting heart rate are measured at rest, mostly during your night — when conditions are the most comparable from one day to the next. The app reads them the way research recommends: as a deviation from your personal average and as a trend over several days, never as an isolated absolute value.
HRV dropping for one night is noise. A week below your baseline is a signal — and that is exactly what the score trends bring out.
Read the details →A metabolism measured, not estimated once and for all
Your energy expenditure is not frozen in a formula filled in on day one: it is recalibrated continuously from your weigh-ins and your actual meals. If your weight moves faster or slower than expected, your targets adjust — the observed energy balance method, the only one that converges on your real metabolism.
Protein targets follow the ranges from recent meta-analyses (up to 2.2 g per kilo for building muscle), adjusted to your goal.
Read the details →The measures, explained
Heart rate variability (HRV)Recovery Resting heart rateVitals VO₂maxLongevity Respiratory rateVitals Blood oxygen (SpO₂)Vitals Wrist temperatureVitals Your baselineMethod Your sleep needSleep Energy expenditure (TDEE)NutritionData and comparisons
Foods highest in protein, iron and moreCiqual table 2025 Whoop, Oura, Garmin, Apple Watch: how they calculateComparisonsYou just read the method.
The app applies it to you.
Everything described here runs automatically on your data, every morning. The iOS beta is open to a small circle.
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