A ten-hour flight due north can be thoroughly exhausting and still produce no jet lag at all. So the tiredness and the jet lag are not the same thing, and perhaps not the same treatment either. What exactly is the difference?
One is a load and the other is a mismatch. Crossing several creates a gap between the and the local hour, and the disturbance appears when the light, the meals and the sleep do not match the internal rhythm. So treatment aims at with timed light and sleep, rather than only at rest. A sleeping pill may ease a symptom without moving the clock itself.
Travel fatigue is what the body collects on the way: long sitting, noise, dry air, stress and dehydration. It can be severe, and it appears on a ten-hour flight due north that changes no hour at all. Rest and drinking help it.
Jet lag adds something entirely different, which is a mismatch. Crossing several time zones creates a gap between the body clock and the local hour, so the body asks to sleep when the destination is awake, and asks to be awake when the destination sleeps. That is not tiredness but wrong timing.
The distinction is not theoretical, because measurements show it. The timing of release and the rhythm of body temperature indicate where the internal clock sits, and adaptation appears in them as a gradual shift of a few hours a day. So there is a physiological process here that can be tracked rather than only a feeling.
Hence the treatment, which is resetting the clock rather than rest. Light at the right time advances or delays the clock, and so does shifting the hours of sleep. A sleeping pill may ease a symptom without moving the clock itself, so it does not shorten the adjustment. And the response depends on the direction, the number of zones, age and the hour of the flight, with no one schedule suiting every traveler.
wat. Jet lag is a gap between the internal clock and the local hour, not a general name for tiredness after a flight.
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The right distinction prevents the wrong solution: rest helps with the load of the journey, while timed light helps reset the clock.
How do we know?
An evidence-based review examined the measurement of rhythm through body temperature and melatonin, and the effectiveness of light, sleep timing and medication.
What is still unknown
The response depends on the direction, the number of zones, age and the hour of the flight; there is no one schedule that suits every traveler.
Learn something?
Where to next
Why is exhaustion from a long flight not always jet lag?flying
What shape does human sleep take when the nights are long?sleep
Does the direction you flew in from change how you play at home?sleep