Jet lag is a tough problem to get sympathy for. Travelling across multiple time zones is often a cause for jealousy, not compassion. But high-speed plane travel to a location that is out of sync with your body’s internal clocks can cause more than just sleepiness. Symptoms of jet lag also include irritability, disorientation, nausea, gastrointestinal distress and trouble concentrating. And an upcoming trip has me worried. I’ll be traveling three time zones to the west for a week of vacation in Alaska, followed by less than 48 hours at home. Then I’m going east to Africa, skipping ahead eight hours, for a total of 11 time zones crossed over so many hours of travel that I’m having trouble doing the math, and I’m not even jet-lagged yet.
When I hit the ground, I will have to function immediately – having conversations, listening closely and absorbing what I’m hearing – all in a country I’ve never visited before.
Wary of the exhaustion to come, I contacted some circadian-rhythm experts for evidence-backed advice about mitigating jet lag. There are ways to ease the pain, I learned. But my itinerary adds some unique challenges.
And still the fact remains: Our bodies have remarkably fine-tuned systems of timekeeping that – unlike the clocks on our smartphones – don’t adjust immediately upon arrival. And because we are all different, there is no one-size-fits-all advice that works, despite any magical strategies you might read about online.
“It’s hard to come up with any general recommendations for jet lag, because it depends on how many time zones are crossed, and in which direction, and on when people usually sleep at home and when they want to be sleeping in the new time zone,” says Charmane Eastman, founding director of the Biological Rhythms Research Laboratory at Rush University Medical Center in Chicago.
But, she adds, planning ahead can make a difference.
“The more days people spend shifting their circadian clocks before the flight,” she says, “the fewer days they will have of jet lag after the flight.”
Inside the brain’s hypothalamus lies a small structure called the suprachiasmatic nucleus, which contains cells that control the body’s circadian rhythm. In most people, this master pacemaker runs slightly longer than 24 hours. Their urge to sleep naturally drifts later over time, a night-owl tendency that makes it easier to travel westward: Going back in time simply requires staying up longer than usual to adjust to the new zone.
The adjustment inside our body happens more quickly, too. According to some estimates, the typical person’s internal clock shifts about 92 minutes later each day after a westward trip, but just 57 minutes earlier after going east. On the flip side, for the minority of people who are early birds with clocks that are shorter than 24 hours, adjusting to going east is easier, says Sabra Abbott, a neurologist at the Northwestern University Feinberg School of Medicine in Chicago.
And it’s not just the one main body clock that has to adapt to a new schedule. Every organ and tissue in our body has its own timekeeping mechanisms. So even as the main clock adjusts, there might continue to be a mismatch between clocks in the heart, lungs, pancreas or liver. Over time, people who do shift work or travel frequently can suffer health consequences from the misalignment of their internal clocks with one another and with the external world. Accumulating research suggests that risks include obesity, diabetes, cancer and heart disease.
Although a single trip is unlikely to carry long-term health risks, Abbott says, jet lag can impair safety and performance, depending on what a traveler is trying to accomplish upon arrival. And despite wide-ranging anecdotal advice that is often conflicting or seemingly impossible (don’t eat, sleep or look at a screen on the plane), studies suggest two basic strategies that can help: carefully timed exposure to bright light and, sometimes, over-the-counter melatonin. But be aware that it’s easy to make mistakes with both of those approaches.
Through laboratory studies that involve abruptly shifting people’s sleeping schedules and measuring how quickly their clocks adjust, Eastman has found that inadvertently getting light at the wrong times after arrival can actually push the body clock the wrong way or make it stall, even if you follow common advice – such as getting morning exposure to light at your destination or immediately going to bed at the new normal bedtime.
But doing it right can speed up the process of adjusting. Eastman has developed a system for creating individualized schedules that include exposure to bright light (outside or with light boxes) and to darkness (by staying inside or using dark glasses). She uses the method starting a few days before she leaves on a trip and says she manages to cross time zones without any jet lag at all. Online calculators for planning ahead, such as jetlagrooster.com, offer similar plans.
It’s an intriguing idea that can also be impractical. The plan Eastman created for my trip would require me to delay my bedtime by a couple of hours each night, beginning about five days before heading east. So I would sleep from 4 a.m. to 11 a.m. near the end of my vacation and then go to sleep at 6 a.m. the next day, using a light box for a few hours before going to bed and staying in the dark for a couple hours after I get up. That’s not a schedule I’m sure I can follow while trying to spend time with friends and family.
Studies suggest that melatonin, which our bodies release in tiny amounts near bedtime, can help when taken in the afternoon before going east or in the morning before heading west. But drugstores sell pills that contain as much as five or 10 milligrams of melatonin, Abbott says, far more than our bodies make. And while taking large doses can make you sleepy, the hormone can also remain in your bloodstream when you get up, which can then backfire. In some cases, as little as 0.3 to 0.5 milligrams is enough. It’s a tiny fraction of what some pills contain, though the timing has to be right.
“It’s one of those things where taking more of it doesn’t help,” Abbott says. “If it doesn’t work, it means you took it at the wrong time.”
Researchers warn against some of the most common pharmaceutical strategies for jet lag. Mixing Ambien and alcohol on the plane, in particular, is a bad idea, Abbott says. But naps when needed are okay. And symptom-masking aids such as caffeine and sleeping pills have their place, though they won’t make your internal clocks shift any faster.
People often develop superstitions about jet lag, believing that something odd worked for them, even if they just happened to get the light exposure right. But even in Eastman’s lab studies, when exposures to light, darkness and melatonin are carefully controlled, some people’s bodies adjust more quickly than others. Shifting the clock may also get harder with age. Such variances may explain why friends can swear by all sorts of strategies that may not work for you.
As I brace for my upcoming jet lag, I’m focused on a single goal: telling all of my body’s clocks to get with the program as quickly as they can.
“The best advice is always just to try to do as much as you can to adapt to the new schedule right away,” Abbott says. “It’s sending a message that this is the new schedule.”