Generic advice
Standard tips may miss your flight times, usual sleep schedule and biological time of light exposure.
Fuseo
A scientific algorithm to adapt to time zone changes
A chronobiology engine that considers your sleep, flights and light exposure to build a plan tailored to your trip.
Why does Fuseo go beyond generic advice?
Fuseo’s calculation
The engine connects your itinerary, body clock and light windows to propose a personal plan.
From flight to plan, in six steps
What happens between the moment you enter your flights and the moment your plan appears.
- Your profileBedtime and wake-up time, chronotype, age, sleep, caffeine: we estimate the timing of your “biological night”.
- Your itineraryEvery flight, connection and clock change is converted to the minute, including the international date line.
- Your simulated clockA mathematical model of the human clock calculates, every 6 minutes, where your body is.
- Hundreds of scenariosBedtime, light, darkness: the engine simulates 500 to 1,400 variants and keeps the best one.
- The real-life filterActual sunlight at the airport, flight time, connections, appointments: anything impossible is replaced.
- Safety checksMelatonin only after a questionnaire, never sleeping pills, drowsy-driving alert.
6 min
time step of the body clock calculation
500 to 1,400
scenarios simulated for a single plan
≈ 2,000
clock points calculated per trip
33
automated tests for every engine release
Under the hood: four scientific models
Models published in peer-reviewed journals, rewritten and assembled by our team. No unverifiable “home-made” formula.
The body clock
A mathematical oscillator that reproduces the brain's central clock and its response to light, developed at Harvard by Kronauer, Jewett and Forger. It is the heart of the calculation: it tells, at every moment, what time it is “for your body”.
Forger, Jewett & Kronauer, J Biol Rhythms, 1999
The effect of light
The same light advances the clock after your lowest body-temperature point and delays it before. The engine accounts for biological time, intensity (outdoors, lamp, cabin) and duration of exposure.
Khalsa 2003 · Zeitzer 2000 · St Hilaire 2012 · Chang 2012
Sleep and alertness
The two-process model: sleep pressure that builds while awake, and the circadian rhythm that modulates it. It predicts your energy slumps and schedules naps and caffeine.
Borbély 1982 · Daan, Beersma & Borbély 1984
Melatonin, as an option
Two effects calculated separately: resetting the clock and helping you fall asleep. Offered only when useful, at a low dose, and after a safety questionnaire.
Lewy 1998 · Burgess 2008, 2010
Models derived from aerospace medicine
These models were not invented for a travel app. They come from research on the fatigue of people who work against the clock: astronauts, aircrews, night workers.
For example, simulation software based on Kronauer's clock model was used to estimate the body clock of 21 astronauts during long-duration missions aboard the International Space Station. The two-process sleep model underpins the biomathematical fatigue models used to assess aircrew schedules in aviation.
Fuseo applies these same principles to your trip, under the supervision of a sleep physician who is also an aerospace medicine physician.
Fuseo is not a fatigue-management tool for on-duty aircrew, nor a medical device.
Medical and scientific expertise
Journeys where every hour matters
These situations show how a plan that considers sleep, light and schedules can help you prepare for arrival.
Validated by our scientific committee
The models, their parameters, the safety rules and the way advice is presented to you have been reviewed and validated by Fuseo's scientific committee, which brings together a sleep physician and an engineer-researcher in sleep technologies.
- Dr Jonathan Taieb · sleep physician, aerospace medicine physician, founder of the Institut Médical du Sommeil
- Dr Maxime Elbaz · engineer, PhD in neuroscience, former technical director of the Sleep and Alertness Centre at Hôtel-Dieu hospital, Paris (AP-HP), eHealth coordinator
What we check with every release
Before every release, the engine is automatically tested on real trips and difficult cases.
8 reference routes
Paris ⇄ New York, Tokyo, Los Angeles and Sydney, both ways, with or without connections.
Calendar traps
Clock changes (hours that do not exist or happen twice), the date line, arriving “the day before”.
Never the wrong way
No light is ever advised at a time when it would worsen the time difference: this is checked against the simulation, over the full 24-hour cycle.
Nothing impossible
No “go out in the sun” mid-flight or at night, no nap during a connection, no sleep during your appointment.
Every profile
Stays of 24 h, 48 h or a week, immediate return, early birds or night owls, short and long sleepers.
If the plan goes off track
Delayed flight, missed light, short night: the plan is recalculated from what actually happened.
What we do not claim
Your body clock is estimated from your answers, without blood tests or sensors: the uncertainty is about one hour, and we show it. Alertness scores are relative predictions, not a medical measurement or fitness to drive. Fuseo provides general information on travel chronobiology and does not replace the advice of a healthcare professional.
And for your next trip?
Calculate my planFuseo calculates your sleep, light and caffeine times from your flights.