Many thanks to Sandra Aamodt and Sam Wang for a marvelous series of articles. Next up: Leon Kreitzman, an authority on questions of the body clock, like why jet lag happens and why teenagers aren’t lazy just because they sleep late. Please welcome him.
Before I hand over to him, however, I’d like to pay a brief tribute to Sir John Maddox, one of the first science journalists and a long-serving and hugely influential editor of the journal Nature. He died at the weekend, and will be much missed by the scientific community.
Now: Leon!
— Olivia
By Leon Kreitzman
The Japanese call it Jisaboke and in French it is les effets du décalage horaire. Whatever the language, the symptoms of jet lag are the same the world over — fatigue, insomnia, disorientation, swelling limbs, loss of appetite, headaches, mood disturbances, bowel irregularity and light-headedness. Jet lag has also been implicated in loss of libido, nausea, sore throat, fall in cognitive performance and even an increased susceptibility to malaria.
It is not just unpleasant. Jet lag can start wars. In 1956, United States Secretary of State John Foster Dulles arrived back in Washington after a long flight to learn that the Egyptians had just bought a substantial amount of Russian arms. Dulles immediately canceled the agreement he had made with Colonel Nasser to bankroll the Aswan Dam project. The Suez Crisis that followed ended Britain’s imperial pretensions, and at the height of the Cold War the Russians had their first foothold in Africa.
Years later Dulles admitted that he had made a mistake in acting so hastily. He blamed it on the effects of jet lag.
During his state visit to China, President George W. Bush blamed jet lag when he couldn’t find which door to use to get off the stage. President Obama looked as though he could have used a couple of days off before the start of the G-20 (though his wife looked great).
Unsurprisingly, Britain’s Iron Lady took jet lag in stride. About to fly off to Japan for an economic summit, Prime Minister Margaret Thatcher said, “Jet lag is an awful nuisance when you’re going straight into talks and negotiations, but we’ll cope . . . we’ll cope all right.” And she did.
When we fly across more than three or four time zones many of us get one or more jet lag symptoms, depending on how far we fly, the direction in which we are heading (most people find it easier to deal with jet lag when flying east to west, chasing the sun) and the time of departure. The more time zones we cross, the longer it takes for the body to adjust to its new time patterns.
Practice does not help. Long-haul airline pilots who are continually flying halfway around the world and back generally feel out of sorts most of the time. Company executives who spend more time in the air than in the office never really adjust, even when they adopt the Lyndon Johnson strategy and try to pretend that nothing has changed and resolutely refuse to reset their watches to local time. American tennis players reckon they need to allow at least a week to get their body clocks back into gear when they fly from the U.S. to England for Wimbledon.
Jet lag comes courtesy of a disruption in your body’s internal clocks, a condition known as circadian desynchronization. Nearly every living creature has a circadian system whose rhythms control the timing of many aspects of biochemistry, physiology and behavior. For instance, virtually all our hormones oscillate with a 24-hour rhythm. Our body temperature falls at night and rises in the day. Other examples of human rhythmic physiology influenced by the circadian system include heart rate, blood pressure and the sleep-wake cycle.
In mammals, the rhythmic source was thought to be localized in a small paired structure of some 16,000 neurones called the suprachiasmatic nuclei (SCN) in the anterior hypothalamus of the brain. The SCN neurones individually are capable of generating near-24-hour oscillations in electrical activity and, collectively, they produce the master rhythm that essentially controls the animal’s crucial rest-activity cycle.
The SCN-generated rhythm is aligned to the daily solar cycle of 24 hours by the photic signals of sunrise and sunset via a light-sensing pigment called melanopsin, found in special cells located in the retina of the eye.
We know now that as well as the SCN, mammalian tissue cells like the liver, kidneys and heart (though notably not the testes) have their own circadian clocks. Put crudely, if rat liver cells are kept alive in a dish for several days, we can still measure a near-24-hour cycle in the activity of genes that code for proteins that have a specific enzyme function in the liver, like alcohol dehydrogenase.
Alcohol dehydrogenase production peaks in the late evening, which is why we can drink more alcohol then than in the morning. About one-fifth of liver enzymes show circadian rhythms, according to Dr. Michael Hastings of Cambridge University. This means that the metabolic capabilities of the liver change dramatically between day and night as different groups of enzymes are turned on and off.
Regulating the production of liver enzymes up and down in a timed sequence enables the liver to do its metabolic job more efficiently. But left to their own devices, the liver’s clocks can fall out of sync with the clocks in other tissues. The SCN signals inform the peripheral cells to adjust the phase of their rhythms, like the pin of a wrist watch being moved a little bit forward or backward.
If we think of the circadian system as an orchestra, then the SCN, synchronized to the external world by the light signals, acts like the conductor, beating out a rhythm that coordinates the multiple rhythmic parts of the body. When the orchestra is in time we get a melody; when it is not there is a cacophony. The same thing happens in our bodies, though how this is done is not at all clear and is the subject of intensive study.
Crossing time zones in a jet plane decouples these rhythms from the natural day-night cycle. (Astronauts in orbit may see 16 dawns and dusks in 24 hours, so it is no wonder that sleeping tablets are the most frequently used medication in space.) On a long trip, the various rhythms fall out of sync and your stomach ends up over Peking, your liver somewhere near Delhi, while your heart is still in San Francisco. Metaphorically speaking, of course.
To counteract jet lag, weary travelers can pick from any number of measures. Some people use special diets; others tap the meridian lines of Chinese medicine every hour or so in flight. Henry Kissinger apparently used to prepare for long flights by adjusting his pre-flight sleep and wake times in the hope of ameliorating the jet lag symptoms.
Melatonin is a popular remedy, though there are considerable doubts as to whether there is much in the way of benefit. Depending on the length of the journey, direction of travel and landing time, seeking (or avoiding) sunlight on landing so as to shift the clocks into alignment with local time is favored by at least one top researcher.
Whether any or all of these methods work seems to depend as much on the faith put in the remedy as to any rational basis.
Help, however, may be at hand thanks to some recent studies on “jet lagged” mice. Giles Duffield of the University of Notre Dame, in conjunction with colleagues at Dartmouth Medical School and Norris Cotton Cancer Center, monitored mice over several weeks, under different light/dark schedules, recording mice activity day and night via electronically rigged running wheels.
Altering the lighting schedules caused a 10-hour delay in the usual mouse circadian cycle, equivalent to a person flying from Athens to Los Angeles. Normal mice took about four or five days to return to their usual activity routine. But genetically engineered mice lacking the Id2 gene adapted twice as fast and were back on their normal running-wheel rhythm in only one to two days.
It goes without saying that mice and humans are different, and as the Id2 gene is important in fetal development, messing with it may be tricky. The study does give a glimpse as to possible ways to cure jet lag by somehow manipulating the gene so as to rapidly adjust our internal clocks and get rid of the lag. But just because we can does not mean we should.
While a scientifically based solution may be bad news for the jet lag remedy business, making long-haul flights easier may not be such a good idea if we are keen to reduce CO2 emissions.
Maybe the answer is to develop two pills. One would inhibit jet lag symptoms and would be available to all essential long-haul fliers like pilots and, say, academics attending conferences. Non-essential long-haul travelers would have to take another pill, which would intensify the effects of jet lag. They could still fly if they wanted to, but most would not and we essential travelers would, at last, be able to stretch out in comfort.
*****
NOTES:
“The Jet Lag Book” (Futura 1984), by Don Kowet
For a description of peripheral clocks in the liver see “Circadian Orchestration of the Hepatic Proteome,” Akhilesh B. Reddy, Natasha A. Karp, Elizabeth S. Maywood, Elizabeth A. Sage, Michael Deery, John S. O’Neill, Gabriel K.Y. Wong, Jo Chesham, Mark Odell, Kathryn S. Lilley, Charalambos P. Kyriacou, Michael H. Hastings Current Biology — 6 June 2006 (Vol. 16, Issue 11, pp. 1107-1115)
For the study of “jet lagged” mice see Giles E. Duffield, Nathan P. Watson, Akio Mantani, Stuart N. Peirson, Maricela Robles-Murguia, Jennifer J. Loros, Mark A. Israel, Jay C. Dunlap. “A Role for Id2 in Regulating Photic Entrainment of the Mammalian Circadian System.” Current Biology, 2009; 19 (4): 297
Charles Ehret attests to Kissinger’s schedule in “Overcoming Jet Lag” (Berkley Publishing Group, 1993)
The connection between jet lag and malaria is from a paper by C. Jairaj Kumar, “Jet lag and enhanced susceptibility to malaria Medical Hypotheses” (2006) 66, 671–685. It is based on Kumar’s claim that “It is often seen that the jet-lagged individuals who visit their family and friends in areas endemic to malaria have an enhanced susceptibility to malarial infection than the local residents.” It is based on the diurnal rhythm of itch sensitivity in humans, which ought to be sufficient teaser to go read the paper.
Olivia Judson is away until summer 2009. 
From 1 to 25 of 130 Comments
I find that taking a short nap right after landing, then getting up and out during the day, and then going to bed on the local schedule seems to help me adjust fairly quickly.
— J. Wongfly on faster planes?
— lou versaceCircadian rhythm is clearly one of evolution’s fine adaptations to a world without jet planes or electric lights. The coordination of organic functions with light and dark, early and late, is emblematic of our genetic adjustment to the rhythms of nature.
These days we consider our finely-tuned organic adaptations a nuisance and an anachronism. We think we have understood these adaptations when we know which neural pathways mediate them. The attitude that circadian rhythm is just an obstacle to overcome is yet another symptom of a world disconnected from its roots, oblivious to its origins in the wild side.
— David MoodyExcellent article on some interesting research. Too bad the weak attempt at humour at the end wrecked it for me.
— RobertI have the greatest difficulty with time adjustment traveling from America to Europe. Staying awake during the first day after deplaning gray-faced and disheveled helps me most to overcome the feeling of being out of sorts.
Interestingly, the autonomous nervous system takes the longest to adapt to the new daily rhythm. I feel hungry at very odd moments for a week.
Since the brain is much like a giant self-medicating gland, a drug affecting the actions of melatonin may provide a remedy.
I have written more about my experience with the effects of melatonin here:
— Peter Melzerhttp://brainmindinst.blogspot.com/2008/06/brain-giant-self-medicating-gland.html
Jet lag is a problem for some individuals — including me. But, I know a woman exactly my age — 66 — who can come back to New York after a ten hour flight plus waiting to change planes in different cities . . . And then enjoy a concert at Lincoln Center followed by having dinner.
Not exactly responding on topic — I am just highlighting individual differences which have to be part of the calculus.
— David Chowes, New York CityI have found that one homeopathic solution works reasonably well when crossing time zones. It is called “No Jet Lag”, and it can be bought in various stores in the US as well as in some other countries. It consists in small tablets to chew.
— Vincent RandyI travel to Europe frequently and would be interested to see if the method I was taught by a businessman on a flight from Amsterdam to LA works for anyone else. It is not for the timid. I do not suffer from Jet lag like used to. It matters not if you are chasing the sun, traveling east or west, but let me say that I have never been to Asia. This is only for European travel to and from the US. 1. Stay up all night long the night before travel regardless of your departure time. 2. Do not sleep on a flight unless it is the oversea leg (for instance if you fly from SF to Denver then to Berlin. Only sleep from Denver to Berlin) 2. Eat a meal BEFORE you board the international leg (the food will probably be better anyway). 3. Tell the flight attendant you will be asleep and to only wake you for breakfast. 4 cover your eyes, use earplugs, take a sleep aid of your choice (I prefer Ambien CR) and finally.. 5 . Awake in Europe or your destination, fully rested and ready for breakfast. Viola! Oh yes, there is a 6th step. Allow for a 30 minute nap (no longer) in the afternoons, around 4 PM local time, if needed. Anyone else use this method?
— ToddSome tips and insights on the international travel!
I follow the Margaret Thatcher view.
Sue
— Sue WhartonI found the best method to alleviate jet lag is to immediately have a good work out ( and a sauna if available), after checking into the first hotel.
I sleep really well afterwards and wake up refreshed and ready for the days ahead.
Cliff, Ein Hod, Israel.
— Cliff LoveI remember reading several years ago, and in more than one article that studies showed the natural circadian rhythm to last 25 hours. The same articles went on explaining that in the middle of the night, somewhere in between 3 and 4 am, it is being reset. The rest time apparently could be triggered by intense-enough light. The 25-hour duration apparently explained why people are not affected at all when traveling to one location 1 hour behind West, but are affected when traveling 1 hour ahead East.
— Giovanni CirianiThanks for mentioning towards the end of the article the flying that academics do to conferences (and to give invited talks around the world). As a frequent flier, I try to catch as much sleep as possible on long-distance flights (not always possible if one has a fascinating seat-mate), eat something light upon my arrival, nap for 3-4 hours on a comfortable bed at the hotel (nothing beats those European beds with downy comforters), and then walk for hours at the destination. Hopefully, the walk can take place in bright sunlight. One then gets a good night’s sleep in the new time zone and is off to give talks, meet with colleagues, etc. The adrenaline and excitement surrounding the new sights and activities neutralizes any jet lag.
I also find that long distance travel imprints memories and helps one’s creativity.
Dr. Anna Nagurney
— Dr. Anna NagurneyJohn F. Smith Memorial Professor
UMass Amherst
I’m suffering from some bad jetlag as I read this. What wonderful supporting evidence for the coworkers teasing me about my haziness at the office today!
— Alex ApostolSeveral years ago, I suddenly became immune to jet-lag when traveling from the east coast to Europe. I sleep on the plane, stay up all day, eat a nice dinner, and then go to bed at a normal time. I will wake up the next morning at 6 am (my normal time) as if nothing has happened, and I don’t suffer from the wee-hour wake-ups.
I have no explanation for my sudden shift. However, I suspect it is psychological - it happened once, accidentally, and now I simply expect to immediately adjust. Interestingly, it takes me quite a while to go to bed at a normal hour when I return to the east coast. And a 9-hour time difference (west coast/Europe) is still quite difficult - it’s too close to inversion.
— Hubble BeagleI once dated an international flight attendant and used to fly with her to Europe. Amongst international flight crews, here is the widely accepted method for handling jet lag:
1. Stay in your own comfortable bed until you need to leave for the airport.
2. Nap only for an hour or so on the plane.
3. When you arrive, take a nap until an hour or so before meal time.
4. Get up, take a stroll and get right on local time.
I have to tell you, it worked every time.
Steve
— Stevehttp://www.travelingprofessor.com
On trips to Europe my wife and I try to take a flight leaving between 6 and 9 p.m. We eat on the plane, then nap for three or so hours and when we land in Europe and check into our hotel, try to nap for an hour or two in early afternoon. We wake late afternoon, walk around, visit a museum and then have supper at 7 or so local time and hit the sack around 10 or 11 p.m. quite well adjusted to European time. This works every time for us. Coming from Europe home, however, jet lag lasts for as much as four days.
— Bill EarlsTodd got it right! Except that I gave up on Ambien CR because of the constipationit causes and switched to benedryl.
— The Shoestring TravellerSleep when you feel like it, eat what and when you feel like eating and let your body sort it out without any tricks. The only “trick” is to drink a lot of water before, during and after the flight to avoid getting sick.
— Mary DibbernYears ago, I’d suffer somewhat from jet lag, I think.
Several years ago, I decided to will away jet lag. With my trips from Phoenix to Bangkok, to the Middle East, and to D.C., I now escape it. I simply follow the temporal routine wherever I find myself and feel quite comfortably adjusted.
My mind-set works fine for me.
— Leon KenmanIf I land in the morning after a long-haul, I try to stay up until 10 pm….or so. Usually coffee, exercise, sunshine, and low amounts of carbohydrates help. If I land in the evening, I eat pasta.
Then, when awakened, I take advantage of it….read, go for early morning walks, etc. It’s fun experiencing early mornings.
I’m not an academic traveling to give keynotes, but I’ve seen a few…..some of them really need the first pill!
— JamieYes, Overcoming Jet Lag by Charles F. Ehret, Ph.D. and Lynne W. Scanlon (that’s me) was a fabulous book and sold hundreds of thousands of copies around the world in many languages. The US Gov’t paid for Dr. Ehret’s research and the US Army Rapid Deployment Forces follow(ed) his program. Someone should tell the White House!
This year his old book was rewritten, reformatted and republished with the title THE CURE FOR JET LAG. You can find it over at http://www.thecureforjetlag where there is also a info-filled blog. THE CURE FOR JET LAG BECAME AVAILABLE ON AMAZON ABOUT THREE WEEKS AGO.
The new version has received excellent reviews, I am happy to report! It’s much better organized and easier to read. Plus we got rid of references to the Concorde and integrated info about Homeland Security issues.
Lynne W. Scanlon
Author with Dr. Ehret
The Cure for Jet Lag
PS Dr. Ehret would say that it is not necessary and is, in fact, counterproductive to take drugs like melatonin to treat jet lag. The body works overtime to get rid of the drug and that, too, affects your recovery time from jet lag.
— Lynne W. ScanlonMy best tips for ameliorating jetlag are: lots of water on the plane, get as much exposure to the sun as possible during the first couple of days at your destination, and force yourself to sleep or stay awake to adjust to your destination’s night time, and no alcohol.
The last time my family went to Japan, we spent the entire next day outside and ate and drank water according to local time. It only took a couple of days before we were on schedule. We did the same thing upon our return on a Saturday. By Monday or Tuesday morning, we were tired but sleeping accordingly to our regular sleep schedule.
For me, it’s all about the sun and telling my body what “time” it is.
— Joanna M. PinedaI travel between London and SF fairly frequently and have found that Vincent’s solution, No Jet Lag, helps greatly. I also stay up until local bedtime then take an herbal sleep aid to help fall asleep the first and second nights.
— SarahI travel most often to Europe, but the following steps work for trips to Asia, too (in fact, the longer the flight, the better the results): 1. When you get on the plane, set your watch to the time at the destination. Convince yourself that that’s what time it is (corollary: when you get there, avoid thinking about what time it is at your point of departure). 2. Sleep every available moment while on the plane. Ear plugs, surly behavior toward chatty seat mates — whatever it takes (corollary: for me, this means alcohol, despite the potential dehydration). 3. When you reach your destination, stay up until the locals go to bed. Usually, I’m excited enough so that that I can push through that occasional middle-of-the night feeling (it helps to have scheduled events or a friend to organize a forced march through mid-afternoon). Peter Melzer is spot on: the last thing to adjust is appetite. I lay waste to the late breakfast in Europe and feel hungry at lunch time for days after I get back. I’ve attended conferences on my arrival date (corollary: going to a conference and having jet lag are pretty much the same feeling anyway) and have used this procedure to good effect for more than 15 years.
— Eric1) Studies on blind humans (not mice!) have convincingly demonstrated that a dose of melatonin greater than 5 mgm, and perhaps closer to 10 mgm, can reset biological clocks. Taken pre-flight at about 9 PM destination time, I find this essential in my US to Europe regime.
— Bill Natale2) Sleeping on the plane as long as possible, aided by a short acting med if needed and business class if possible, is important. I agree, skip the meal.
3) Provigil, developed to aid shift workers whose malady is very close to jeg lag, taken at 8 AM on arrival day 1 and maybe day 2, keeps one awake at the “right” times and speeds adjustment. (Rx required)
4) In answer to one question, faster planes will not help; they are the problem. Anecdotally, Concorde passengers were among the worst affected, and in the days of clipper ships, no one complained of “sail lag.”