ChronoTwin

Built on the well-established scientific foundations of chronobiology, the app takes into account what constrains your natural rhythm — social jetlag (the gap between your internal clock and your imposed schedule) and time-zone changes (jetlag) — to predict and best anticipate your body's adaptation. ChronoTwin also factors in your personal sensitivity to weaker or symbolic signals (moon, classic biorhythms, weather), which you can tune yourself, to give you advice on your rhythm today, as well as 3 or 7 days ahead.

Computation of your circadian cycles (energy peaks and dips, sleep windows), advice on adapting your activities to best reconcile your natural rhythm with your constraints, and personalised sleep recommendations. The advice engine is deterministic — same data, same results — and the daily brief uses generative AI to structure and phrase that advice in a readable way.

A roughly 24-hour cycle that regulates sleep, body temperature, hormones (melatonin, cortisol) and alertness. It is the scientific core of ChronoTwin: the app uses it through your chronotype and schedule to estimate your daily peaks and dips.

Shorter-than-24-hour cycles, typically about 90 minutes, that modulate attention, energy and focus. ChronoTwin reflects them in sleep windows and recovery tips.

Circadian rhythms are real, well-documented biological cycles driven by light, chronotype and sleep: they are what ChronoTwin's forecasts are built on. Classic biorhythms are sine waves computed from birth (physical, emotional, intellectual) with weak scientific validity; they are offered as optional, clearly labelled signals, and you choose their weight.

It is the chronic gap between your natural rhythm (measured by your chronotype) and the schedule actually imposed by work or daily life — for example waking at 5:40 when your body would aim for 7:30. Unlike travel jetlag, it does not resolve on its own: ChronoTwin measures it continuously and helps you reduce it.

It uses the ChronoTwin profile: 6 questions about your free-day wake and sleep times, your wake inertia, your peak slot, how early your weekday alarm pulls you, and how solid your sleep is. The result is a ChronoIndex from 0 to 100 (100 = strongly morning) plus a morning, intermediate, evening or dolphin profile, used to estimate your sleep and performance windows.

ChronoTwin is a digital chronobiological twin: it models your rhythm from your profile, cycles and environment to help you anticipate your days and nights.

Yes. Your Twin is end-to-end encrypted on your device before any sync. Our servers only store an opaque ID and an unreadable blob. We cannot decrypt your data.

Sign in to your account, then pick one of three routes: enter your secret phrase, pair the device from another device that is already unlocked (QR or code valid for 3 minutes), or import your backup file (.ctwin) with the secret phrase from that time.

If no device is still unlocked, your synced Twin and your backup files become permanently unreadable: nobody, including us, can decrypt them. Local data on devices that are still unlocked stays intact, and you can start over with a new secret phrase.

From Settings you export an encrypted .ctwin file and store it wherever you want (iCloud Drive, Google Drive, a password manager, a disk). It stays unreadable without your secret phrase and restores your Twin even after a cloud purge. No automatic backup is made on your behalf.

A biorhythm is a repeating cycle computed from your date of birth. The classic model uses three cycles — physical (23 d), emotional (28 d), intellectual (33 d) — to which ChronoTwin adds other signals for a more complete reading, always presented as personal-sensitivity signals, not established facts.

Each cycle is a sinusoid with a fixed period: we count the days elapsed since your birth, then apply sin(2π × days / period). Everything runs locally in your browser or on your device.

The circadian foundations (chronotype, social jetlag, time-zone adaptation) rely on chronobiology literature. However, biorhythms and some environmental signals lack solid scientific validation: they are clearly distinguished in the app and their weight is adjustable. ChronoTwin remains a reflection and planning tool, not medical, financial or professional advice.

No. ChronoTwin is an informational app. For any health, sleep or occupational fatigue issue, always consult a qualified professional.