TRAVEL, TIME ZONES, AND JET LAG MINUS THE JET
Even for those who normally sleep well, nothing can disrupt sleep like travel. Our circadian rhythms didn’t evolve with jet planes and air travel in mind, so if you’ve flown long distances, you’ve almost certainly experienced jet lag at some point.
If you're going to be a member of the Jet Set and fly off to Katmandu for coffee with King Mahendra, you can count on contracting Jet Lag, a debility not unakin to a hangover.
According to the Smithsonian’s Air & Space Magazine, the term “jet lag” was first used in 1966. “If you’re going to be a member of the Jet Set and fly off to Katmandu for coffee with King Mahendra,” wrote the travel writer Horace Sutton, “you can count on contracting Jet Lag, a debility not unakin to a hangover. Jet Lag derives from the simple fact that jets travel so fast they leave your body rhythms behind.”
In other words, when we change time zones, we also change sleep zones. But it takes a while for our body clocks to sync up with the clocks where our bodies currently are. Though we mostly associate jet lag with being groggy, in some extreme cases I’ve experienced something closer to a sleep-deprivation coma. And according to researchers from Rush University Medical Center in Chicago, jet lag can lead to depression, gastrointestinal problems, impaired judgment, and long-term problems such as cognitive impairment and menstrual-cycle disturbances. Flight attendants, whose working lives are defined by constant travel across time zones, even show a higher risk of cancer.
Weary with toil, I haste me to my bed,
The dear repose for limbs with travel tired;
But then begins a journey in my head,
To work my mind, when body’s work’s expir’d.
—William Shakespeare, “Sonnet 27”
Till Roenneberg, an expert on sleep cycles, is so convinced of their importance that he makes sure in his own life he never needs an alarm clock in the morning. As he has shown, jet lag goes beyond air travel, which is why he coined the term “social jet lag.” He explains, “A biological clock is ticking in every person, producing an individual daily timing. This defines a person’s unique ‘chronotype,’ which can vary greatly between individuals. For some people, internal midday may coincide with external midday. Others can reach their internal midday several hours before or after external midday. Social jet lag measures this difference between our external social timing and that of our internal clock.”
My own travel kit includes salt-free almonds and walnuts, cut vegetables, and on long flights my favorite: goat cheese and honey-baked turkey in a small container with an ice pack.
This internal clock is located in a part of the brain that controls circadian rhythms of all kinds throughout the body—including sleep, temperature, and the digestive system, among others. It does this by processing light from the retina and by the expression of so-called clock genes. A study by researchers from the Beth Israel Deaconess Medical Center in Boston found a helpful tool to beat jet lag: food—or, more accurately, the absence of it. “When food is plentiful,” they wrote, “circadian rhythms of animals are powerfully entrained by the light-dark cycle. However, if animals have access to food only during their normal sleep cycle, they will shift most of their circadian rhythms to match the food availability.” Studying mice, they discovered a “master clock” in a region of the brain (the dorsomedial nucleus) that can reset the circadian rhythm when faced with a shortage of food. The thinking is that when food is not an issue, lightness and darkness synchronize our sleep cycle. But when food is scarce, another system kicks in to synchronize our sleep cycle with our ability to find food.
So they suggest we can adjust our eating schedules to trigger our circadian rhythms to adapt more quickly. “A period of fasting with no food at all for about 16 hours is enough to engage this new clock,” says the study’s senior author, Dr. Clifford Saper. For example, for a fourteen-hour flight the researchers suggest that you stop eating two hours before flying and continue your anti-jet-lag fast during the entire flight, aiming for a total of sixteen hours. For those who can’t go that long without food—especially those prone to fainting—there are other steps to take to ease the transition between time zones while still avoiding that $14.99 dry turkey on dry rye: bring your own nourishing snacks. My own travel kit includes salt-free almonds and walnuts, cut vegetables, and on long flights my favorite: goat cheese and honey-baked turkey in a small container with an ice pack. If you don’t have anything to eat, it is going to be much harder to resist the airline’s offerings of salty pretzels, chips, and “freshly baked” cookies. And of course the most important thing for me is to continue to drink a lot of water throughout the flight. In fact, depending on the length of the flight, I buy a bottle or two once I get through security, so I’m not dependent on the kindness of the flight attendants.
Or, if you prefer, there’s an actual diet for jet lag called the Argonne Anti-Jet-Lag Diet, named for the Argonne National Laboratory near Chicago, where it was formulated by the biologist Charles Ehret. With this method, four days before your trip you alternate two cycles of feasting and fasting, switching every two days, making sure to link up the last fasting day with the day you travel. The diet was tested in 2002 by U.S. National Guard troops going to and from South Korea. The anti-jet-lag group was 16.2 times less likely to experience jet lag on their way home from South Korea than the control group was.
Most people are usually running around a day or two before their trip so they tend to be preloaded with sleep deprivation even before they set foot on the plane, which will further complicate the condition.
Dr. Charles Czeisler, former chairman of the board of the National Sleep Foundation, raises a red flag about another common travel misstep: starting off already tired. “Most people are usually running around a day or two before their trip,” he said, “so they tend to be preloaded with sleep deprivation even before they set foot on the plane, which will further complicate the condition.” And try to avoid the aptly named red-eye flights altogether. Instead, Czeisler advises, fly in the afternoon if you’re headed west and in the morning if you’re going east. “The airlines have finally woken up to this issue,” he says, “so there are now plenty of earlier flights to Europe.” If you have to take a night flight, he suggests at least trying to get in a nap the day before. “Taking a nap before you’re exhausted can actually reduce the adverse effect of being awake at the wrong time of day. This is what we refer to as prophylactic napping.”
Not surprisingly, technologies are being created to help us beat jet lag. Researchers at the University of Michigan are developing an app called Entrain, which uses sophisticated math and data analysis to tell users how and when to utilize light to more quickly shift their sleep cycle in a new location. And then there is Re-Timer, an eyeglasses-like piece of headwear that can be used not just by travelers but also by shift workers who need to make regular adjustments to their circadian rhythm, especially in the winter. Worn over the eyes, it exposes the wearer to a simulation of outdoor light, which, when used in the morning, can help reset our body clock so that we can fall asleep at the right bedtime.
Another way to try to beat jet lag is to not adjust to local time at all. “For a quick trip, it probably does not make sense to try to adjust to the new time zone,” says Dr. Chris Winter, medical director of Charlottesville Neurology and Sleep Medicine. “Instead, you want to try to do things to make it feel like the trip never happened.” Depending on which way you’re going, this just means sticking to your home time zone and staying up later or going to bed a few hours before the locals, with corresponding wake-up times. “If you’re on vacation, you should ask yourself this question, which many people never bother to do: Is there any reason I should adjust to this new time zone?” asks Czeisler. “People feel compelled to change their routine once they change their wristwatch, but it’s not always necessary—and not always a good idea.”
For a quick trip, it probably does not make sense to try to adjust to the new time zone. Instead, you want to try to do things to make it feel like the trip never happened.
My advice, based on what has worked for me through my many travels across multiple time zones, comes down to arranging my schedule so that I have plenty of time for sleep—even if it means building in an extra day for travel. I’ve talked to many executives who fly around the world and go into meetings exhausted, unable to stay awake; they often end up offending people who may have worked for weeks getting presentations ready for that meeting.
And what about on the plane itself? Though the airlines don’t always make it easy, there are some things you can do to at least make sleep more likely. I’m actually a little bit obsessed—okay, totally obsessed—with trying to do everything I can to make my flights more sleep-friendly. That’s because I travel so much, and I’ve learned over time that a little preparation goes a long way. I have my sleeping gear permanently packed in my carry-on: an eye mask, noise-canceling headphones, earplugs, herbal teas (including lavender and licorice), and my favorite neck pillow. I always like to dress comfortably, even if it is a short flight, and I wear only flat shoes when I travel. Why would women wear high heels on a flight? I have seen more than a few sprinting in stilettos through airport terminals, a sight as exotic as seeing an ostrich dash across the savanna.
The difficult truth of air travel is that a great deal of the experience is out of our control. Variables from turbulence and crying babies to chatterbox seatmates and jolting announcements can thwart even the best-laid sleep plans. As Betty Thesky, the author of Betty in the Sky with a Suitcase, wisely warned, it helps to set the bar low. “Passengers will often have unrealistic expectations on an all-night flight,” she says. “They think, ‘I’ll sleep on the plane and be ready to hit the ground running’ when they land at their destination many time zones away.” But given that you don’t know how rested you will be when you land, it’s best to allow time for some real sleep before you schedule meetings or hit the tourist spots.
Excerpted from THE SLEEP REVOLUTION: Transforming Your Life, One Night at a Time by Arianna Huffington. Copyright © 2016 by Arianna Huffington. Excerpted by permission of Harmony Books, an imprint of the Crown Publishing Group, a division of Penguin Random House, LLC.
The Sleep Revolution, by Arianna Huffington will be available April 2016 everywhere books are sold. Pre-order your copy today to receive bonus gifts and start transforming your life tonight. Learn more at AriannaHuffington.com.