How to beat jet lag: what the research really recommends

You land in Los Angeles in the morning, the airport sits in the best California light, long-haul traffic rolls in every few minutes – and after two hours at the fence you are fighting your eyelids. Or the other way around: after the night flight to Singapore you lie wide awake in your hotel room at three o’clock. Anyone who crosses time zones for spotting trips knows this. This guide explains how jet lag happens, what the research actually recommends and how to plan the first days at your destination so that as little spotting time as possible is lost.

Jet lag in one sentence

Jet lag is a body clock that is out of sync: after the flight, your body still lives in the time zone you came from, while light, meals and appointments outside follow a different clock. The symptoms only disappear once both clocks match again – and that does not happen in one go but in small steps each day.

The medical definition used by professional societies (International Classification of Sleep Disorders) requires a flight across at least two time zones. Typical signs are trouble falling and staying asleep, strong tiredness during the day, weak concentration and memory, a general feeling of being unwell and digestive problems. Pure travel fatigue is something different: you get that even after a long north-south flight with no time difference, from little sleep, dry cabin air and sitting for hours. Travel fatigue is usually gone after a good night’s sleep, jet lag is not.

How the body clock works

The central pacemaker sits in the brain, in the so-called suprachiasmatic nucleus of the hypothalamus. Throughout the day it controls body temperature, hormone release, hunger and sleepiness. In the evening the pineal gland releases the hormone melatonin, which signals “night” to the body. In the early morning hours, core body temperature reaches its low point – that is the moment when it is hardest to stay awake.

Important for understanding jet lag: this clock does not run exactly 24 hours. In a much-cited study under strictly controlled lighting conditions, published in Science in 1999, the intrinsic period averaged around 24.2 hours in both young and older adults. So every day the clock has to be reset slightly. The most important signal for that is light, which is reported directly to the pacemaker by special cells in the retina. Meals, exercise and social contact have an effect too, but a much weaker one.

Why light is not just light

Whether light moves the clock forward or back is decided by the time of day – more precisely, the time from the point of view of your body clock, not the local time at your destination.

• Light in the evening and in the first half of the night (before the temperature low point) pushes the clock back. You get tired later and wake up later.
• Light in the early morning (after the low point of the body clock, which according to the CDC lies about two to four hours before your usual wake-up time) pushes the clock forward. You get tired earlier and wake up earlier.

This is exactly where the most common trap lies: after a big jump east, the morning at your destination still falls into the “night” of your body clock. Bright light right after sunrise may then work in the wrong direction. You therefore have to work out the times when you seek or avoid light from your home time.

East or west: the big difference

Because the body clock tends to lengthen anyway, the flight west is usually easier: the day gets longer, you go to bed later – that suits the body. On the flight east you have to shorten the day, fall asleep earlier and get up earlier. The CDC puts the average adaptation at about an hour and a half per day westbound and only about an hour per day eastbound.

Route from Frankfurt (daylight saving time)	Time difference	Direction	What the body has to do
New York	6 h behind	West	Push the clock back – usually quite doable
Los Angeles	9 h behind	West	Big jump, early waking in the first days
Singapore	6 h ahead	East	Pull the clock forward – much tougher
Tokyo	7 h ahead	East	Similar to Singapore, trouble falling asleep in the evening is typical

Singapore and Japan do not observe daylight saving time, so in the European winter the gap shrinks by an hour. The US, on the other hand, also changes its clocks, so the difference to New York and Los Angeles stays the same except for a few weeks in spring and fall. With very big jumps, it can also happen that the body clock adjusts “the wrong way around” – it then shifts back even though you flew east.

Before the flight: shift your clock at home

The CDC recommends shifting your sleep gradually toward the destination time two to three days before departure – about an hour per day. Before an eastbound flight, you go to bed an hour earlier each evening and get up earlier; before a westbound flight, correspondingly later. Morning light after getting up supports moving things forward, evening light the shift backward.

That is not always practical in everyday life, certainly not with a job and a family. But even a one- or two-hour head start makes the jump at your destination smaller. Two more levers before the flight:

• Start well rested. If you board with a sleep deficit, you amplify jet lag symptoms. Do not spend the last night before the flight packing.
• Choose your arrival time deliberately. If you have some leeway when choosing a flight, pay attention to when you land. How typical long-haul arrival and departure times are distributed in Europe is shown in the article when long-haul flights land and depart in Europe. An early-evening arrival after a westbound flight is often ideal: get some light, eat, then sleep at a reasonable local time.

On the plane: think in destination time

Set your watch to destination time at boarding at the latest and follow it. If it is night at your destination, try to sleep – with an eye mask, earplugs and no screen. If it is day at your destination, stay awake, even if it is hard, and allow yourself at most a short nap.

Then there are the classics, which do not reset the body clock but ease travel fatigue: drink enough water, get up regularly and move around, and go easy on alcohol. Alcohol may help you fall asleep faster, but according to the CDC it makes sleep more restless and promotes fluid loss. Why the air on board is so dry and what cabin pressure does to your body is explained in the articles on cabin air and pressure on your ears.

On very long nonstop routes of 16 hours and more, all of this applies in amplified form – details on these routes are in the post on ultra-long-haul flights. If you fly with a stopover instead, you can use the layover for movement and daylight and perhaps pick up a few sightings along the way, as described in the guide spotting during a layover.

After landing: light, sleep, caffeine

The most important principle for the days at your destination is: live on local time right away – eat when the locals eat, sleep when it is dark. The fine-tuning is done by light.

Exercise outdoors combines two benefits at once: daylight and activity. For spotters this is practical, because a few hours at the fence automatically get you into the fresh air. Just make sure the time of day matches your flight direction.

Melatonin: what the studies say

Melatonin is the most thoroughly studied remedy for jet lag. A Cochrane review (Herxheimer and Petrie, 2002) evaluated ten randomized trials. The majority showed that taking melatonin close to bedtime at the destination eases jet lag on flights across five or more time zones – especially eastbound. Doses between 0.5 and 5 mg worked similarly well; higher doses brought no additional benefit. Side effects were rare.

Not every institution draws the same conclusion. The UK’s NHS explicitly does not recommend melatonin for jet lag because the evidence is not sufficient for it. The CDC, by contrast, describes its targeted use and considers 0.5 to 1 mg often enough to shift the clock. It does not recommend high-dose melatonin above 5 mg.

Timing is decisive:

• Eastbound: before bedtime at the destination.
• Westbound: melatonin plays a smaller role here. The CDC describes taking it during the phase that your body clock still perceives as early morning – in practice that is complicated and more a case for medical advice.
• Badly timed, melatonin can slow down the adjustment and make you tired during the day.

Sleeping pills and other remedies

In its 2007 overview, the American Academy of Sleep Medicine (AASM) lists three approaches against jet lag: planned sleep times, deliberately shifting the body clock with light and melatonin, and relieving symptoms with sleep aids or stimulants. Short-acting sleeping pills can help in the first nights but do not reset the clock. The CDC explicitly advises against antihistamines and long-acting sedatives from the benzodiazepine group because they can impair mental performance and increase the risk of falls. Special “anti-jet-lag diets” and fasting plans are popular, but the evidence for them is much thinner than for light and melatonin.

Short trip or long journey: which strategy fits?

Using jet lag as a spotting advantage

Jet lag takes your sleep, but it can also give you light. After a westbound flight to the US, you wake up early in the first days. Instead of staring at the ceiling in your hotel room, you can use it for a first morning session – low light, calm air without heat shimmer and often a wave of arrivals. At Los Angeles Airport, an early session like this can be a real win. You will find more planning tips in the guide to the spotting trip to the US. For choosing the lit side, the post on the sun position at the photo spot helps.

After an eastbound flight it is the other way around: in the evening you stay awake for a long time and in the morning it is hard to get out of bed. In Singapore, for example, it is worth scheduling sessions toward late morning and afternoon in the first days. What Singapore Changi Airport offers in terms of spots is in the profile and in the article plane spotting in Singapore.

And after coming home? The return flight brings jet lag too. If you land back from Asia at Frankfurt, you are awake early in the first days – ideal for a morning session at the Zeppelinheim viewing platform when the long-haul arrivals come in.

What to keep in mind

• Stay awake first, then drive. Strong daytime tiredness after the flight is a real accident risk. If possible, make the first trip to the spot by public transport – options in the article getting to the spot.
• Plan by your body, not by the clock. When light helps depends on your body clock, not on local time.
• Drink enough, go easy on alcohol. Both help against travel fatigue and poor sleep.
• Do not expect a miracle cure. Light, sleep planning and, if applicable, melatonin shorten the adjustment, but jet lag can hardly be prevented entirely after big jumps.
• Clear up health questions with a doctor. With pre-existing conditions, regular medication or recurring severe symptoms, seek medical advice beforehand.

Conclusion

Jet lag is the price of traveling faster than the body clock can keep up. With big time jumps it can hardly be avoided entirely, but it can be shortened considerably: with a sleep rhythm shifted in advance, light at the right time of day, sleep on the flight according to destination time and – after talking to a doctor – low-dose melatonin before bedtime at your destination. Eastbound you need more patience than westbound. If you plan the first days realistically, you can even turn early waking into an additional morning session at the fence.