Jet lag from Johannesburg to New York: what to expect

How long does jet lag last from Johannesburg to New York?

Unaided, westward shifts settle somewhat faster than a day per time zone: about 5 days for this one. S6 S7

This plan targets 4 days.

That's what the plan aims at, not a promise — bodies vary.

For this trip that's 1 day sooner than the unaided estimate, on the effort level that fits around a working day.

On night one the plan's bedtime is 21:40, early by New York's clock, and it moves later night by night, reaching 23:00 by night 5.

Studies of aircrew point the same way: after large shifts, westward adaptation runs roughly 50% faster than eastward S6 S8. This trip is on the quick side of that.

What does the plan say for a typical Johannesburg to New York flight?

Departs

11:00 Johannesburg time

Lands

20:10 New York time

In the air

about 16h 10m (estimate)

Light, the first full day

20:00–21:00 Seek bright light (delay shift)

Keep it dim, the first full day

05:30–07:30 Avoid bright light (sunglasses / dim room)

Last caffeine, landing day

13:45 on the plane

Last caffeine, first full day

13:00

First night's sleep

21:40–05:30

Westbound flights often go by day, so this example leaves Johannesburg at 11:00 and lands in New York at 20:10 in the evening, after about 16h 10m in the air.

The flight time is our estimate for a nonstop from the distance, and the trip is set in January. It's the default traveler from the calculator: usually asleep 23:00 to 07:00, no melatonin, Real Life effort.

In July the gap is 6 hours, not 7, because New York moves its clocks and Johannesburg doesn't.

On board, the plan keeps you awake apart from a short nap at 06:00 New York time, saving the real sleep for the night in New York.

The day before you fly, the plan keeps your morning dim, 07:00–09:00 Johannesburg time, and the sun is up in Johannesburg by about 05:30 in January, so plan on sunglasses for the commute.

On landing day your last coffee comes on the plane, at 13:45 New York time, and the plan has none between landing and your first night's sleep. From 05:30, when you wake from that first sleep, it allows it again, until 13:00.

January days are short in New York: about 10 hours of daylight. In January the sun sets in New York at about 16:57, so the 20:00 light step the day after landing comes after dark. It has to be bright indoor light.

At over 16 hours in the air, this is one of the longest flights there is.

You land too late in the day for a light step on landing day, so the first one is the next day, at 20:00.

Note the order: the plan keeps you out of bright light until 20:00, then sends you outside. Light before your body's low point pushes the clock later S1, which is only welcome once the low point has passed.

The sun is already up for the morning dim window (05:30–07:30), so stay inside with the lights low, or wear sunglasses if you have to be out S1.

What helps after flying west to New York?

Going west, you want light before your body's low point, which usually means bright light in the evening and staying up a little later S1. Bright light first thing in the morning works against you. East vs west explains why this direction is the easier one.

On a shift this size, starting before you fly pays off. The Frontiers review describes moving bedtime 30 to 60 minutes later each day for 3 to 4 days before a westward trip S1. The plan's version is one night: bed at 00:00 the night before you fly, an hour later than usual.

And the flight home from New York?

New York to Johannesburg is the same 7 hours the other way, eastward. It's the harder direction: about 7 days unaided, and the plan targets 5. Jet lag from New York to Johannesburg has the details.