The first hour after a long-haul flight

The clock in the brain runs on a cycle a little longer than a day and it resets by light. Morning light pushes it earlier; evening light pushes it later. Fly west across six zones and the body needs to go to bed later, which it likes; fly east across six and it needs to go to bed earlier, which it resists. The Jet Lag Simulator takes the two cities, computes the shift and its direction, and gives a schedule of when to seek light, when to avoid it and when to sleep for the days around the flight.

The day before

Shift by an hour or two in the direction of travel. Going east, go to bed an hour early and get up an hour early, with bright light on waking. Going west, the reverse. One day of this takes a day off the recovery; two days take two. Most people do none of it and the simulator lists it anyway, because it is the cheapest gain in the plan.

On the plane

Set the watch to the destination when the door closes. Eat by it, not by the trolley, and sleep by it if the schedule says sleep. Water rather than alcohol, which makes the sleep on the plane worse and the first day slower. The eye mask and the earplugs from the polar realm’s packing list do the same job here.

The first hour after landing

If it is morning at the destination, get outside into the light, walk, and stay awake until a normal local bedtime. If it is evening, keep the sunglasses on, get to the hotel, eat something and sleep by the local clock even if it is early. The mistake in the first hour is the nap: an afternoon sleep on arrival tells the clock that the local afternoon is night, and the shift takes two more days.

The trips where it matters most

Raja Ampat and Danum Valley are eight or nine hours east of Europe, and the first dawn on the reef or the walkway is the thing you flew for; a wasted first day is a real loss. The Galápagos and Manu are six or seven hours west and easier. Antarctica from Europe is four or five hours west and the ship’s two days across the Drake do the adjusting for you. Ladakh is only four and a half hours east and the altitude is the real problem, which the oxygen field note covers.

Caffeine and the afternoon

Coffee in the destination’s morning helps; coffee after the destination’s lunch delays the sleep that the clock needs. The simulator marks the hours where it helps and the hours where it hurts, and the schedule for the second and third days is mostly about light and coffee at the right times.