The Frontal Cortex

Jet Lag

Jet lag is an annoyance of modern life for which our pleistocene brain is completely unprepared. This ability to zip around the globe, to trapeze from time zone to time zone, is an invention of the late 20th century. Unfortunately, the brain is an organ of routine, equipped with a stubborn circadian clock. We are wired to expect a 24 hour day, and when our day extends far beyond that, the result is a set of symptoms that remind us we are far from home.

The problem of jet lag is also an interesting case study of stress. Hans Selye, the great Canadian endocrinologist, defined stress as the bodily response to any demand (stressor) that throws our body out of allostatic balance. (The response is an attempt to get that balance back.) Unfortunately for the globalized world, jet lag is one of those things that knocks us off balance. The end result is a large stress response, even if we don’t typically associate duty free shopping, bad plane food and cabin boredom with stress.

This was made clear by a series of clever studies led by Kei Cho, a neuroscientist at the University of Bristol. He compared female flight attendants working for two different airlines. One company gave employees a 15 day break after working a transcontinental flight, while the other company gave employees a 5 day break. After controlling for a slew of variables, Cho found that the cabin crew working for the second airline – they were given fewer days to get over their jet lag – showed higher levels of stress hormone, impaired spatial memory and temporal lobe atrophy. This difference remained even when he controlled for the total amount of jet lag, suggesting that giving the mind time to adjust and recover is the crucial variable.

These upsetting results built on Cho’s earlier work demonstrating that transmeridian travel leads to much higher levels of stress hormone (cortisol), both before, during and after the long flight. (The cabin crew didn’t show higher levels of stress when working domestic flights.) This implies that the brain is bracing for its ordeal, preparing itself to deal with the arduous task of resetting its circadian clock. In fact, the mundane event appears so stressful that long haul flights cause menstrual disturbances in approximately 35 percent of female aircrew.

The moral, I suppose, is that modern life is full of rituals that clash with our internal machinery. (I’d wager that rush hour traffic is like getting jet lag everyday.) We obviously need transmeridian flights, but it’s worth realizing that such journeys come with a real cost. And if we make these journeys rather frequently – if we’re like those cabin crews working on little rest – then those costs just might be permanent.

Comments

  1. #1 Michael Nielsen
    June 3, 2010

    I’m reminded of William Gibson’s beautiful albeit tongue-in-cheek theory that jet lag happens because “your soul gets left behind”. (http://www.williamgibsonbooks.com/books/pattern.asp )

  2. #2 OftenWrongTed
    June 3, 2010

    My Airline gave adequately long rest-periods after flying a long flight. As a Captain I was expected to be aware of the potential performance of myself & crew when I made decisions during our flight. Our crews reported that after a long flight, we saw a slowing of reaction-time, decision-making time, and potential errors in computations. Crew resource management and challenge and response checklists got us to our destination. Recovery from a trip was largely an individual matter involving that person’s regime of exercise, diet and rest.

  3. #3 Eric Lund
    June 3, 2010

    One company gave employees a 15 day break after working a transcontinental flight, while the other company gave employees a 5 day break.

    I suspect something got lost in translation here. I’m sure an airline crew doing one long flight will be doing a second long flight shortly thereafter. The airline has to bring them back to their home base somehow, and having them work a return flight seems the most obvious way to do so. And no airline (at least in the US, and this is increasingly true of Europe as well) can afford to leave a crew at a layover airport for five days in a row, let alone 15. Also, the mention of not feeling this stress on domestic flights leads me to ask whether they are discussing intercontinental rather than transcontinental flights; there are several countries that have domestic flights crossing multiple time zones (US, Canada, Australia, Brazil, Indonesia, …).

  4. #4 NoAstronomer
    June 3, 2010

    That has to be wrong. No (US) airline gives a 5 DAY break after a transcontinental flight, let alone 15. Maybe 5/15 hours. Yes I do know a couple of flight attendants.

    Besides all this shows is that people feel better after a break. You could equally well apply this to people working the cash register at McDonald’s (not that there’s anything wrong with that).

  5. #5 OftenWrongTed
    June 3, 2010

    Comments to Eric and NoAstronomer: My rest periods for long flights were 24-48 hours: You are both correct in that the crew continues after a rest period by bringing the plane back home. I mostly worked 12-15 days per month for my career.

  6. #6 Parag
    June 3, 2010

    I think the most salient point of this post was summed by Jonah thusly: “The moral, I suppose, is that modern life is full of rituals that clash with our internal machinery.” Jet lag is just one of many examples. More commonplace ones include things like carpal tunnel syndrome and other repetitive stress disorders, chronic lower back pain among people who DON’T do heavy lifting (no doubt caused partially by sitting in awkward positions for long stretches of time in office chairs or the car), and all of the so-called diseases of prosperity like coronary disease, metabolic syndrome, type II diabetes, and everything else that comes with our contemporary, highly-processed food diet.

    One of the things that puzzles me about modern society is that we often work too hard to earn more money, which we then use to buy medical care/treatments to remedy problems caused by working so hard in the first place!

  7. #7 Michelle Dawson
    June 3, 2010

    Meanwhile, as I found out, the inability to suffer from jet lag can be considered pathological. See http://autismcrisis.blogspot.com/2010/05/circadian-prison.html Go figure.

  8. #8 James
    June 3, 2010

    “I’d wager that rush hour traffic is like getting jet lag everyday.”

    Should be “every day”, not “everyday”. See http://www.elearnenglishlanguage.com/difficulties/everyday.html

  9. #9 djlactin
    June 4, 2010

    I wonder why ‘jet lag’ seems to depend on travel direction. I work in Korea and travel to Canada for visits. When I go to Canada (West to East), my jet lag lasts about a week. When I fly to Korea, it lasts only a day or so, or may not even occur. Whyzis?

  10. #10 Gia
    June 4, 2010

    I have a question. What is the relation between ‘jet lag’ and aging if there is a connection? According to my experiences, it seems easier to adapt time deference when I was younger. I used to work as a consultant traveling around places every week, never felt being bothered by jet lag. But, nowadays, I can’t fall sleep in other time zone. I always wonder its because of aging, or because of my brain become stiff due to lacking of exercise?

  11. #11 Eric Lund
    June 4, 2010

    @djlactin: There are two factors at work here. One is that most people find it easier to shift their schedules later than to shift earlier. Studies on winter-over crews in Antarctica, where there is no sunlight to provide day-night cues, show that if the crews are not forced to maintain a particular schedule they tend to shift about an hour later per day (this may be related to the recurrence interval of tides). So most people find it easier to move west across time zones than to move a similar distance east. The other factor, which is only anecdotal (but I am not the only one to have experienced it), is that it helps to arrive at your destination in the late afternoon or early evening, which is normally the case when you travel from North America to East Asia. That makes it easier to adjust to the new schedule since you only have to stay awake for a few hours until it’s close to normal bedtime at the destination. I have only been to Asia a few times, but I have never had jet lag problems going there (as opposed to coming back). Eastbound transpacific flights, depending what part of North America you are going to, often arrive in the morning, leaving you to get through a whole day before you can try to sleep on a normal schedule.

  12. #12 Roga
    June 4, 2010

    I can’t remember where exactly (but I’m sure it was probably a blog i read) I recall something about a jet-lag hack, a way to get your circadian rhythm in sync immediately rather than waiting through a resting period. The idea was that if you starve yourself, your body’s instinct to stay awake to get food overrides the natural circadian rhythm you had been on and effectively resets it once you do get your food and go to sleep. Another way this might be viewed then from the perspective of Jonah’s article is that the stress levels (levels of cortisol could be tested for because I am not sure there have been any tests carried out on this theory) significantly overshoot those of the trans meridian flight alone and are satiated once food is obtained. Basically if the body has evolved a mechanism to stay awake in order to obtain food then it will essentially over ride jet-lag because the body will have “desired” to stay awake longer than usual and will presumably be able to get you back onto a normal 24 hour cycle more effectively. Thoughts?

  13. #13 N
    June 4, 2010

    I’d comment on Rush Hour traffic:

    My theory is that we take on different personas when we’re driving. When we look at the front of a car, we tend to see it as characteristics of a human face. We personalize and even anthropomorphize our cars, to a certain degree. Many of us *become* our cars, in some ways, when we drive them.

    Then we’re forced into a different set of social rules and conventions. Some of which apply to our “other lives” – some of which, do not. (ever see someone pick their nose while they’re driving?).

    In many ways – we’re freer, in our car-personas. We are more mobile. We are supermen-and-women. We go places we could not go on foot. We can travel much faster. We seem to have superhuman reflexes. We impress or intimidate eachother, and project our inner values; bulk, utility, and strength for the truck-drivers. Speed and reflex, for the sports-car enthusiast. Pragmatic consideration for the economy car driver. We drink poisonous drinks. (gasoline or diesel).

    Yet, we’re dependent on our elixir. We can’t live without it. If we don’t obey arbitrary, and sometimes – obviously stupid rules, (like stopping at a 4-way stop sign when there is no other visible traffic) – then all civilized order breaks down, and we risk anarchy and death. As free as we seem at times, when we jam roadways past their design capacity, we feel helpless and powerless again. We even see that we could be driving on sidestreets and making better progress, if only we hadn’t made the bad choice of getting on the freeway. We could be on public transportation, and getting there faster, if only we hadn’t chosen to get into our car. We might get to our destination on time, had we chosen to leave an hour earlier. Had we studied harder in school, we could have chosen a profession where we could work at home, we wouldn’t have to deal with this torture, or be a party to this huge waste of time and resources, each and every weekday. Had we chosen to live a simple country-life, with horses, on a farm, we wouldn’t be so stressed out. Had we been born into a super-wealthy family, and fallen into the “executive class” we could be taking the helicopter to work this morning, and looking down at the poor miserable souls stuck in traffic instead. If only the Internet could someday replace the need to actually show up at work, then most of these people would not need to drive every day.

    Then we shift blame to the slow people in front of us, who just aren’t in enough of a hurry, or aren’t sufficiently motivated to get to work in time, or succeed in life, and are therefore, in OUR way, and begin to develop a case of road-rage.

  14. #14 Anthony Sebastian
    June 4, 2010

    From jetlag — don’t go against mighty Sol — to road-rage. With other disturbances in between.

    Physico-psychological stress can sometimes overcome allostatic capacity, the ability to change set-points for changing circumstances. The system can call for allostasis only so long when allostasis adapts the system to prolonged physical and psychological stress. If too strong and prolonged, the overload following becomes itself a source of stress, seemingly stresses eating stresses, building stress-mass.

    To avoid the inevitable breakdown, we need to get smarter. That means taking the level of ”sapiens” self-organization to a higher plane, one with greater complexity of self-organization compared with that in the past, both biological and cultural complexity. Unless we want to stagnate biologically and culturally, unaware of the adverse consequences of stagnation.

    If we cannot solve the problems we have now, how will we deal with whatever greater problems might come. Who thinks with me that we allowed runaway population growth because we did not understand it mathematically? We cannot stagnate cognitively; we cannot let mathematical ability not grow.

    Mathematical cognitive skill marks only one cognitive domain among a sea of domains that need ontological advancement — getting smarter.

    Stagnation would lead to more rapid extinction than if we self-organized a culture for species-specific allostasis, an interindividual cultural allostasis, allostasis of a cultural planetary organism. How long for that to evolve?

    We certainly have a paucity of thinkers who collectively aim for a planetary organism in their thoughts about the human potential for leading self-fulfilling lives. Who paints a picture of happy human-bees in a healthy productive hive with completely self-contented bees thinking with an advanced level of cognition, one hardly imaginable at our current level.

    “Easy to bandy ‘advanced level of cognition’”, you say. “How can we think different than we do? We can’t reprogram our thinking program.” Yes, we can. A first step, asking how can we reprogram, produce a version upgrade with new features. DOS to Windows-7.

    If you want to upgrade a program without writing a new one from scratch, you had better understand the program you want to upgrade. But you have to use that program as a means to learn about it. No need to think that an obstacle, as we do that all the time to seek our advantage or assess the soundness of our thinking. We metacognize.

    Raising metacognition to expert status might seem an ernormous hopeless task. That may underestimate the kernel’s potential, of the acorn becoming the oak tree. The seed of metacognition could germinate and a new cognitive entity emerge autonomously.

    Jonah Lehrer knows about metacognition, as he wrote an article on the subject published in Seed magazine.

  15. #15 christopher babayode
    August 30, 2010

    Great article. Two of the issues this article raises can be dealt with naturally. The missing perspective is that the flying environment is an alien one. The closer and more like the sea level we can make it the easier it will be to deal with jet lag.

    For example not many people know of the inverse relationship cortisol has with vitamin c. Large (orthomolecular) doses of vitamin c blunt cortisol release in the bloodstream and affect the stress dynamic. It is also interesting to note that our closest mammalian cousins the apes have bloodstream vitamin c levels many multiples more than us humans.

    The use of high quality vitamin c regularly over time will give relief to anyone with elevated cortisol.

    As for the observation about hormones and female flight attendants I would suggest a survey of how many flight attendants took the pill, to be a good place to start looking at the problem. Dietary factors can influence hormones provided counter steps are not being applied which upset the homoeostatic and natural functioning of the body. The use of contraceptives can sometimes be a disturbing factor

    The use of hemp seed and oil is one such food item invaluable at helping hormone balance naturally.

  16. #16 Fabiola Phillips
    September 30, 2010

    So North Korea has introduced a successor to the regime. This might in fact be a solid thing for the reason that it might bring a little stability to that unsettled part of the world. I think it’s not probable a Berlin Wall kind situation will take place consequently best to choose a more softening approach as has occured with China it’s most important supporter

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