With long-haul flights a big part of my work, I’ve spent a lot of time trying to overcome jet lag, and beat it at its own game. Some travel writers said that they barely notice changes to their circadian rhythm, and that long-term travel leads to more of the same. But my own body is different. As an insomniac who turned to meditation to help lull my body to sleep, jet lag has been a real thorn. At the beginning of my travels, I handled the woozy dissonance with mid-afternoon naps and a week of wandering through life as a zombie.
It wasn’t enough.
I decided to deep dive into research and articles about sleep, jet lag and circadian rhythms. In the process, I came up with a system that has done wonders for me in minimizing jet lag when I shift time zones, and helps me sleep better generally.
While this isn’t my typical narrative post, many readers write complaining about jet lag and asking how to make it easier. I thought I would share what I’ve learned. Below, how to beat jet lag while you travel, including some important tips to keep in mind before you even leave home that will help it last a shorter time. And if you’re like me where sleep has long been an issue: keeping some of these tips when you aren’t traveling will likely help you sleep better.
LAST UPDATE: SEPTEMBER 24, 2022
Circadian Rhythm Studies Go Beyond Jet Lag
Crucial to understanding how jet lag affects the body is to first start with circadian rhythm, essentially the body’s “clock” that governs our sleep and wake cycles.
We’ve long read pop culture pieces about “night owls” or “morning people” and how one is inevitably better than the other. The truth is, your genes affect your body clock and may be contributing to you being one of those two types of people. It’s not that you don’t necessarily want to get up early, or can’t do night shift; it’s that your genes are affecting the rhythm your body is best suited for and making it harder for you.
This piece focuses on jet lag, when that body clock is essentially out of sync. But the circadian rhythm itself is also important to learn about as a building block for understanding why that can happen. It’s a 24-hour process in the body that affects a lot more than sleep, and also has profound impact on the immune system, metabolism, the temperature of our bodies, hormones, and a lot more.
As you’ll read below, there are different organs and systems in the body that have their own circadian rhythms, controlled via a “central clock” in the brain called the suprachiasmatic nucleus, or SCN. Almost every organism on the planet has its own circadian rhythm, from plants to animals to people.
More and more studies have pointed to a circadian component that impacts body processes, so much so that a whole field of medicine has been growing: chronomedicine (or chronotherapy). It started in the 1970s when researchers saw that mice cancer responded better to treatment given in decreasing doses over a 24-hour cycle. Later research showed that circadian rhythms were important for other conditions, too, proving that certain genes run on a 24-hour cycle, and thus so does the physiology of what those genes impact.
In 2017, the Nobel Prize in Physiology and Medicine was awarded to three circadian rhythm researchers who discovered a “clock” protein that, like an actual clock, changes depending on the time of day. In animals that are nocturnal (like mice), the build up of the protein occurs at night; it’s the opposite for creatures that are not nocturnal.
Because of how circadian rhythms affect the body’s systems, mice research showed when a big dose of paracetamol was given in the AM, nothing concerning resulted. But, when the same dose was given at night, it adversely affected their livers. So essentially, this subset of medical practice has shown that there are optimal times and less than optimal or even hazardous times for medical interventions in certain diseases, including prostate cancer.
First: let’s go back to the basics.
Wait, Where Does the Term “Jet Lag” Come From?
Jet lag is a fairly recent term, which makes perfect sense because airplanes are a fairly modern invention. The question I had in writing this piece was: when did it first pop up in writing?
There is a May 1958 piece in Popular Science magazine that alludes to its effect on our bodies. Called “Trials of the Jet-Age Traveler,” it warns that flying around the world:
“at nearly the speed of sound will throw your eating and sleeping schedules off as never before. … You can make a mental adjustment by simply resetting your watch while whizzing over the time zones of Paris, Beirut or Karachi. But your body doesn’t change its routine so easily.”
Then there was a 1969 study by the Federal Aviation Administration, entitled “Time Zone Effects on the Long Distance Air Traveler,” which notes that pilots in the 1930s submitted early write ups about body clocks. The study is clear to mention that as of 1969 there was no definitive study about jet lag, but that desynchronization of the circadian system was a serious problem for travelers and pilots alike. (I also like that its final suggestion is moderate exercise and a warm bath to help induce sleep.)
From government studies, jet lag hopped into popular culture via the media society consumes. Per an Air and Space Magazine article, the first appearance in newspapers was from a Los Angeles Times article on February 13, 1966, by Horace Sutton:
“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. Jet Lag derives from the simple fact that jets travel so fast they leave your body rhythms behind.”
Google’s nGram graph for jet lag in books from 1800-2008 show that it was first mentioned in the late 1940s, with the term gaining traction throughout the latter part of the 20th century, peaking in the year 2000.
What Is Jet Lag and Why Do We Get It?
Jet lag is the lag time between our internal body clock and the place we are now inhabiting.
Jet lag is essentially a chronobiological problem. The same issues arise not just when we fly long distances, but also we we do shift work. Both require your body to make changes to how your body clock perceives time. And it’s not just humans, either.
In her book Chasing the Sun, science journalist Lisa Geddes notes that daily sun cycles are important to many different species, from insects (honeybees can get jet lag too!) to plants, algae and so much more. A 2019 study at Yale University delved into plants and their night-day cycle. Joshua Gendron, leader of the Gendron Lab at Yale and senior author of the study, noted that the circadian clock “is important to plants in much the same way that it is for humans.”
As for us humans, much of our biology varies between day and night in a natural rhythm our bodies sink into with ease. Change those rhythms via shift work, long-haul travel, or insomnia, and the effects on the body are manifold, a “lag” in what the body anticipates and what it’s getting moment to moment.
Since this is a travel website, I’ll start with long-hauls. When we travel long distances, our circadian rhythm is temporarily out of synch with the new destination’s time. This means that internally we anticipate dawn and dusk to fall at certain times, which are suddenly at different times than what’s happening outside. The desynchronization affects not just sleep, but also body temperature, blood pressure, hormone regulation, when we get hungry and how hungry we are.
You know that feeling when you wake up at 3am after a long-haul flight and you wince rolling over to check the clock because you just know it’s not actually day time but your body is all NO GET UP NOW IT’S NOT NIGHT IT’S ALL A LIE? Yeah, that. When this happens, I feel like a perpetual daytime / nighttime bird, unaware of which is which, dreading the middle of the night awakening.
That SCN I wrote about above is a “master clock” in our brain that uses our exposure to light to coordinate all of the workings of our organs. Located in the hypothalamus, “an area of the brain just above where the optic nerves from the eyes cross, it synchronizes our circadian rhythm while also keeping everything it in line with the Earth’s rotation.
We’re still learning about the SCN and other “timekeepers” in the body affect the molecular mechanisms of our circadian rhythms. A study from August 19, 2021 found that a gene called Npas4, which we already knew played a role in balancing excitatory and inhibitory inputs in brain cells, appears to also be a master timekeeper for the brain’s circadian clock. Scientists hope that by learning more about the molecular underpinnings of the circadian clock, they can help optimize it to improve health, and potentially also treat sleep disorders.
Per Dr. Smith L. Johnston, a flight surgeon and the chief of the fatigue management team at NASA, it takes about a day to adjust to each time zone we cross. But not all jet lag is the same. The body’s production of melatonin, a sleep hormone produced by the pineal gland to signify to our body that soon it will be time for rest, affects our body’s internal time measurement system. That system is also influenced by the direction we travel; heading west is easier on our body than flying east. A 2016 study shows that not only is it easier to recover from westward travel, but that hopping over a few time zones might be harder on our body clocks than a larger gap.
Driving the point home, a 2017 study that looked at sports teams and travel ascertained that traveling eastward affected athletic performance (in this case, of sprinters) for up to 3 days following arrival. What about westward movement? The study concluded that traveling west is less of a doozy for the body to process, simply affecting waking times more than peak performance.
For example, it would take you about eight days to recover from a westward trip across nine time zones, if you did nothing to fight it. But if you cross the same number of time zones going east, recovery would take more than 13 days, according to the model. This recovery time is worse than if you flew smack across the globe, crossing 12 time zones, which is about the distance from New York to Japan.
This is all because the body’s internal clock has a natural period of slightly longer than 24 hours, meaning that the body has an easier time with lengthening the day (heading west) than shortening the day (heading east).
I find it takes me a week to adjust when returning from Vietnam, but with the tips below I’ve beat jet lag’s interference with my day-to-day living.
Prior, I simply curled up in a ball on the carpet at 3pm and called it a day.
Symptoms of jet lag
When your body clock is all over the place, it’s very hard to sleep well. I am not a great sleeper generally, though I’ve vastly improved my sleep issues over the years, so when I’m jet lagged I am basically a zombie.
Some of the symptoms of jet lag include:
- Difficulty falling asleep
- Inability to stay asleep through the night
- Daytime exhaustion
- Brain fog
- Lower coordination
- For some, increases in allergies and/or asthma (see below for more)
- For some, stomach discomfort (see below for more)
- Mood changes like being irritable or emotional.
Jet lag: not so fun! But with the tips in this piece, you can hopefully minimize the symptoms and get better sleep in a new destination.
Can Jet Lag or Shifted Sleep Affect our Immune System?
Jet lag isn’t simply about sleeping a little better as you travel. As mentioned earlier, there are plenty of studies about the effects long-term circadian rhythm changes have on the body. Some even discuss the role of circadian rhythm in neuropsychiatric illnesses, where scientists have found that clock genes have been implicated in the pathophysiology of several diseases including bipolar disorder, schizophrenia and depression.
Stabilization of sleep and circadian behaviours is providing new approaches for the treatment of psychiatric illnesses via chronobiology and chronomedicine research.
Even your immune system has a circadian rhythm, as does your neuroendocrine system and many other function loops in the body. Per a 2015 study about body clocks and the immune system:
Most immune cells express circadian clock genes and present a wide array of genes expressed with a 24-h rhythm. This has profound impacts on cellular functions, including a daily rhythm in the synthesis and release of cytokines, chemokines and cytolytic factors, the daily gating of the response occurring through pattern recognition receptors, circadian rhythms of cellular functions such as phagocytosis, migration to inflamed or infected tissue, cytolytic activity, and proliferative response to antigens. Consequently, alterations of circadian rhythms (e.g., clock gene mutation in mice or environmental disruption similar to shift work) lead to disturbed immune responses. We discuss the implications of these data for human health and the areas that future research should aim to address.
Essentially, shift work or continuous jet lag tranches may alter the natural immune system’s protective responses. Chronic misalignment of our body clocks — for example, when eating and sleeping patterns conflict with the natural light-dark cycle, or with prolonged shift work — is associated with higher risks of conditions like metabolic syndrome, cardiovascular disease, neurological conditions, and cancer.
In the chart below, cells of the body’s central clock in the SCN (top) and of other body clocks in other tissues, including in the immune system (bottom), have a clock based on autoregulatory feedback loops (middle right inset). This clock controls the rhythmic expression of various types of molecules.
The SCN clock regulates the different peripheral clocks (including in immune cells) via humoral, neuronal, and systemic cues. The circadian regulation of the immune response is therefore not one body clock, but an integration of different signals from the central (SCN) clock, and then all of those peripheral clocks found in the immune cells, the organs, and even areas of infection of the body. (Source, specifically relating to inflammatory conditions and the circadian clock.)
It’s also worth noting that these peripheral clocks adjust to the new time zone / shifted time at different rates, so your SCN may be more adjusted than, say, one of your peripheral clocks – like your liver. (Source)
A study published in early 2020 took that a step further, and genetically-engineered mice to remove the BMAL1 clock gene. The authors wanted to find out how the body clock could influence infection-fighting cells, specific to pneumonia. They already knew that mice had a harder time fighting off pneumococcal bacteria when they were infected during the day, versus at night. This experiment aimed to make that difference stronger by removing the mice’s ability to regulate body clock functioning.
“We were really surprised to find that these mice, which had no clock in a set of immune cells, were more resistant to bacterial pneumonia,” noted senior study investigator David Ray, PhD, in a write-up about the study. “Almost everything we’ve learned about the body clock so far, whether it’s studied in shift workers or experiments in mice, says that disrupting the body clock makes people and animals more likely to get ill, not less.”
In addition, in a study released in January 2021 in the journal Genome Research, scientists reported that our circadian rhythms affect our ability to fight off diseases to a greater degree than previously realized. Lead study author Jennifer Hurley talked with Inverse about her study, noting that while scientists knew chronic disruptions to the circadian clock over a lifespan can lead to increased risk of certain diseases, they didn’t know how the disruption lead to an increased risk.
“We had observed that all of the diseases that were associated with chronic circadian disruption were also linked to inflammation, which is a product of the immune system. However, a deep understanding of how the clock controls the immune system, in cells or in organisms, didn’t exist. This study aimed to help fill that gap in knowledge.”
So what did Hurley’s team find? They found that macrophages, which are specialised cells that help in the detection, and destruction of bacteria and other harmful organisms in the body, play a critical role in the body’s levels of inflammation. And, it turns out, that they also affect the functioning of the body’s circadian clocks. From the Inverse piece:
Macrophages, Hurley and her team discovered, time changes in their responses to both pathogens and stress via the circadian control of metabolism. But the precise nature of their timing was wholly unexpected, Hurley says.
“We learned the circadian control mechanisms in the cell are more complex than we previously believed, meaning that there is likely more that circadian rhythms control than we knew,” Hurley says.
“Our study has a lot of potential to forward science.”
Since the body clocks we have affects many different systems we need to function, it’s even more reason to try and beat jet lag when you travel. Sleep hygiene and good sleep goes far beyond waking up and feeling rested, and extends to the workings of the immune system itself.
Can time of day affect medication efficacy for COVID-19?
Increasingly, scientists are looking to the circadian rhythm of the body to help manage the diseases of the present, and the treatments of the future. With the pandemic, coronavirus studies include a look at chronomedicine’s findings with how time of day can impact the body’s responses to medication – and even whether they will be helpful or harmful.
“When we saw the controversy surrounding the use of ibuprofen, we wanted to fully understand why this drug was beneficial to some people, but having negative effects on others,” said Harry Karmouty-Quintana of University of Texas Health. In a report published in the British Journal of Pharmacology called The case for chronotherapy in Covid‐19‐induced acute respiratory distress syndrome, Harry’s team suggests providing anti-inflammatory medicine at specific times of the day, which would impact the body’s response to the medication without interfering with its fight against COVID-19.
“We hypothesize that the intrinsic circadian clock of the lung and the immune system may regulate individual components of CRS, and thus, chronotherapy may be used to effectively manage ARDS in COVID‐19 patients,” notes the study – which dovetails well with the sections on mast cells, below. We know mast cells have their own circadian rhythm, and that they release cytokines when they degranulate (release inflammatory substances into the blood). It follows, per Harry’s team, that administering medication based on the schedule of that inflammatory flood could optimize the body’s attempts to heal.
Per the conclusion:
“This would mean that afternoon is the preferred time window for drug administration whereas intake at night should be avoided. This is particularly important when administering immune modulators where a single dose is usually given. Furthermore, the goal of chronotherapy in COVID‐19 is to avoid reaching steady‐state drug levels; as in the case of anti‐inflammatory therapy, these would dampen the inflammatory response directed towards the virus.”
How to Beat Jet Lag: My 5 Tips to Help You Get Over it Faster, and Sleep Better
This list of tips has not been reviewed by a doctor, but are simply what I have found works for me as I’ve traveled the world. I’ve found a combination of various tips to minimize jet lag, culled together from my reading and testing, that truly mitigates the effects of jet lag. As a long-term traveler jet lag is a significant problem. I was incentivized to make it more bearable.
Now that people are not traveling much, these tips can still be used to get a more restful sleep, abide by a more advantageous sleep schedule, or ensure that going from day to night – whether for studies, work or more – is done with ease.
Use these five tips to beat jet lag when you travel, or just join the legions of people who want to sleep sleep better, with less 4am interruptions. By addressing jet lag and/or circadian rhythm dysfunction, you can help your sleep, travel recovery time, daytime lucidity and your health. Science tells us our bodies.
1. Melatonin! Does melatonin help you sleep better? It can, in smaller doses than you think.
I use melatonin in two different ways, both at 300mcg (not milligram) doses — way smaller doses than the dosing recommendations on the over-the-counter medicine you buy at your local pharmacy or on Amazon. Less is more for me, and frankly doctors seem to agree.
In his 2018 post “Melatonin: Much More Than You Wanted to Know” over on Slate Star Codex, Scott writes that, “most existing melatonin tablets are around ten to thirty times the correct dose.”
He continues that
Based on a bunch of studies that either favor the lower dose or show no difference between doses, plus clear evidence that 0.3 mg produces an effect closest to natural melatonin spikes in healthy people, plus UpToDate usually having the best recommendations, I’m in favor of the 0.3 mg number. I think you could make an argument for anything up to 1 mg. Anything beyond that and you’re definitely too high. Excess melatonin isn’t grossly dangerous, but tends to produce tolerance and might mess up your chronobiology in other ways. Based on anecdotal reports and the implausibility of becoming tolerant to a natural hormone at the dose you naturally have it, I would guess sufficiently low doses are safe and effective long term, but this is just a guess, and most guidelines are cautious in saying anything after three months or so.
The thing is, many people are using melatonin as a sleep aid—but that isn’t what it’s for. It acts more like a “dimmer switch”, reminding your body to wind down for bed.
Per the New York Times, “Taking a melatonin supplement is sort of like taking a dose of sunset, tricking your body into feeling like it’s nighttime. It doesn’t put you to sleep as much as it tells the body that it’s time to sleep.”
The dosage recommended on most bottles is quite a lot higher than studies have shown our bodies need, and while I am not a doctor I have found great success with a severely scaled-back dosage. Even less dosing (0.3mg as the ideal) is effective when testing for insomnia in 50-years old or more patients. When I take the recommended doses (even as small as 1.5mg pills), I find my next day is adversely affected.
So what’s a traveler to do?
- Buy the correct dose of melatonin. This means grabbing 300mcg pills, not the giant pills you see at the local pharmacy. Options at this dosage include Sundown Naturals or Life Extension brands. If you’re looking to test purity / reliability of your supplement, see LabDoor’s writeup here, via SSC.
- Timing varies and the studies about taking melatonin for jet lag are not as clear as the dosing ones. Personally, after arriving at my destination I tend to sleep just fine – the issue is waking up in the middle of the night. In those cases, I will go to bed without a problem, but waking up at 4am I will take 1/2 of a 300mcg tablet to get back to sleep again. I will not do this for longer than 3 days.
- Alternatively, if the jet lag has thrown off my circadian rhythm such that it can’t remember it’s bedtime, I take 300mcg just before bed.
For more about melatonin – a lot more – see Examine’s long review of the studies and efficacy here.
- In addition to melatonin, a 2018 study also found that Pycnogenol, a pine park extract from France, could reduce the severity and length of jet lag symptoms. Per the Washington Post, “this research showed that supplementing with Pycnogenol actually reduced the duration of time individuals felt jet-lagged by nearly 50 percent and improved feelings of fatigue, visual impairment and inability to sleep.” Dosing is 50mg a day, once or twice daily starting two days prior to the flight, and continuing for 4 days during the adjustment to a new time zone.
Now that I’m not traveling any longer, I still take 300mcg of melatonin nightly, at 8pm (with a target bedtime of 10pm). It’s really helpful for getting tired when I need to, and for a restful sleep. Any doses higher than 500mcg mean that I end up with far too vivid dreams and feel groggy in the next morning.
2. Restricting blue light exposure at night can shorten jet lag symptoms and help keep your sleep schedule stable.
Part of regulating circadian rhythms is to get in the habit of signalling to your SCN and your body when it’s time for bed and when it’s time to wake. In a modern world, we are exposed to quite a lot of artificial “blue” light (even though it looks white), a daylight signaler to our minds. Be it LEDs, fluorescent lighting, or the backlit screens of our portable devices, it’s easier for our bodies to get confused. It’s even more confusing when your body clock thinks it’s halfway around the world.
The title of a January 2015 study in Proceedings of the National Academy of Sciences summarizes it all: “Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness.” Per that study, people not only produce 55% less melatonin when using an iPad at night, but after tucking into bed thereafter it took extra time to fall asleep. Further, the sleep had less rapid eye movement (REM) time. The next morning, those iPad users felt sleepier and had difficulty feeling awake.
In contrast, those who read books instead awoke with more alertness. If that wasn’t bad enough, the study found that next night the same iPad users had their circadian rhythms out of whack, delayed by well over an hour. This means that they began to feel tired later, because they had read on a blue-light device before bed the prior evening.
Is there consensus that blue light can affect circadian rhythm?
Generally yes, though there is some recent dispute about how much the phone or computer’s blue light affects the body vs. acts a stimulant. In the dissenting camp, Professor Russell Foster from the Sleep and Circadian Neuroscience Institute at the University of Oxford in England. He believes that the issue is stimulating our nervous systems via devices, not the blue light itself. And we do spend a lot of time on our devices.
That said, many scientists disagree with him. The Sleep Foundation says that blue light found in our handheld devices “can delay the release of sleep-inducing melatonin, increase alertness, and reset the body’s internal clock (or circadian rhythm) to a later schedule.” Live Science says the same about our smartphones and tablets, reminding us that studies have found that blue wavelengths “suppress delta brainwaves, which induce sleep, and boost alpha wavelengths, which create alertness.”
While yes, using them less may certainly create a less stimulating environment before bed, blue-blocking is not for naught. At least that’s where the science is at as of December 2021.
Since I have started restricting blue light at night, I have found it a lot easier to shift my body’s clock when needed, have slept more soundly, and have felt more alert in the morning. I also do this as a matter of course now, instead of just when warding off jet lag. I sleep more soundly as a result.
Ways to restrict blue light at night
Using F.lux on your laptop and Android phone, and Night Shift on iOS devices
* see below for additional F.lux uses for jet lag
I have personally forced every friend and family member who doesn’t have F.lux on their laptop to download it immediately, and promised them that it would change their lives. I’ve never found one program that has this big an impact on my sleep cycle and comfort as I work in the evenings.
I’ve always been more productive in the evenings, usually starting around 4pm. I will happily work away well into the night. And of course, after pecking away for hours, I found it difficult to shift into sleep. F.lux automatically blocks blue light from your screen at sunset based on your location, and lightens it in the morning. It’s a free programme, and I encourage you to donate to them because it’s basically pillows for your eyes.
I’m not affiliated with them, nor did they ask me to write this. I just evangelize wildly because it’s made such a huge difference to the way that I can work productively in the evening without feeling terrible the next day.
Using iOS’ New ‘Night Shift’ or Android’s Twilight App.
If you’re using an iPhone or iPad, the new “night shift” mode allows you to block blue light, essentially “Fluxifying” your device for evening use, which can help you sleep.
For those on Android, the Twilight app allows you to do the same with your phone or device, blocking blue light starting at dusk.
Using Blue-blocking Glasses
If you’re not looking to add a programme to your laptop, you can block your blue light using these extremely sexy (ok not so much) orange glasses: Uvex Skyper Blue Light Blocking Computer Glasses with SCT-Orange Lens. These allow you to read on whatever device your heart desires, but block blue light in the process.
For a less clunky versions, see these DONNA blue blocking lenses (good for smaller faces). I bought the DONNA glasses and they come with a tiny screwdriver, a sturdy case, and replacement screws for the sides.
Another option is the best-selling (and apparently celebrity endorsed?!) SWANNIES tinted blue light blocking lenses (available in several sizes), or their untinted version (available in one size only).
3. Shift your time zone BEFORE you travel to help you adjust faster
Many pieces address how to beat jet lag after you land, but I have found that preemptively signaling to my body that I am “in” that new time zone helps shorten my adjustment period considerably.
How to shift your time zones ahead of time.
- I set F.lux to the new time zone 5 days before leaving, so my laptop blocks blue light during that country’s nighttime hours.
- If it’s a particularly important trip — such as a time where I need to give a keynote or presentation, I’ll wear those blue blocking glasses around the house during nighttime in my new destination. Yes, this makes me look like an idiot. No, I don’t wear them out of the house. Yes, I have found that it makes a difference.
- At the same time as I start my F.lux schedule, I take melatonin at what will be the beginning of dusk in my new destination. So if I’m heading to Saigon but presently in Montreal, I’ll take 1/4 of a 3mg pill of melatonin at 9am Montreal time for the 5 days leading up to departure. This does mean that I struggle more with sleep during those few days, but the process truly limits time’s impact upon landing.
- If you want specifics of how to prepare ahead of time, the free Jet Lag Rooster app will show you exactly how to shift your schedule based on your bed time, waking hours, and travel plans.
- Another app for shifting time zones is the paid Timeshifter, which touts a combo of neuroscience and tech to help take sleep pattern, chronotype, flight plan, and a range of personal preferences into account when helping you switch time zones. Endorsed by Silicon Valley and NASA astronauts, it has gotten great reviews and not only tells you how to shift your sleep schedule, but also when to take naps (and when to caffeinate) as you go. Its approach is based on personalisation, since everyone reacts a little differently to light and light changes. The founder claims that if you follow the app’s instructions to a tee, “you can shift the clock three to four times as fast as normal.”
- If you want a one-stop shop version of this plan: invest in Re-Timer glasses. Re-Timer aims to slowly shift the time of day that light is received by your eyes to complement your travel schedule. Instead orange lenses, these glasses emit green light, worn for about 50 minutes per session. This helps stimulate the parts of your brain responsible for regulating the 24-hour body clock. The company is quick to note that they are not seeking to fully modify your sleep schedule prior to departure. Instead, the glasses retime your body clock in small steps before you travel and continue the process after you arrive. Created by two sleep psychologists, the glasses were tested by the F.lux team here.
Wearable smart devices may help you shift your sleep and adjust faster.
Given the sheer volume of constant travelers, there is a big push to develop technology that helps microanalyze sleep cycles and potential jet lag.
In late 2019, engineers affiliated with the Lighting Enabled Systems & Applications (LESA) Center at Rensselaer Polytechnic Institute developed a way to deliver personalized advice using smart wearable technology. In the study about this advice, published December 2019 in the journal PLOS ONE, scientists developed a series of algorithms that can analyze biometric data recorded by a smart device to recommend the optimal combination of light exposure and sleep for a person’s particular bio-rhythms.
“The circadian and sleep processes are also very tightly related to your mental state and how alert you are,” said Agung Julius, one of the co-authors on this paper. “If you try to do something in the wrong time of day, your alertness is not going to be as effective as if you do it in the right time of day as defined by your circadian clock.”
There are constant developments in the chronobiology space, and I’ll be updating this piece as they come out.
Using an eye mask and ear phones are important for good sleep hygiene.
Similar to the sunrise-mimicking alarm clock below, when shifting your time zones it’s important to really block out light at the time you want your body to get to sleep. I use a comfortable sleep mask originally recommended by someone else, and it’s come with me all around the world. (It’s on my travel packing list too). Sleep Master Sleep Mask with velcro, perfect too if you’ve got a small head like I do and regular ones just fall off easily.
For ear plugs, same logic: making a sleep environment quiet and dark is very important when regulating the body clock. I use these Moldex Spark Plugs, used for NASCAR races, because my ears are ridiculously small and these compact down the the right size. They come in boxes of 200, so like me you may find yourself doling out earplugs to everyone around you.
Morning light + exercise: help optimize your circadian rhythm to help overcome jet lag faster
A short but effective tip: work out in the mornings when you are in the new time zone, getting your blood flowing and waking you up even more. Initially, I was more awake at night and exercised then. Doing so simply woke me up further and made it harder to sleep.
It’s also important to expose yourself to natural morning light if you can, especially in the initial days of jet lag. This is often hard as I want nothing more than to crawl under the covers and stay there, but even if it means opening the window and sticking my head out as soon as I get up, it helps remind my body that it’s actually day time.
A way to help optimize morning circadian rhythm is using technology. The Philips Wake-Up Light Alarm Clock with Sunrise Simulation, below, is built to mimic the sun rising over the planet. It starts out with a naturally bright hue and then gradually deepens the light over 30 minutes, just prior to your wake-up time. By imitating the rising of the sun, you can help shift your body faster to your current time zone.
As for exercise, it is helpful for phase‐shifting the effects of bright light to help conquer jet lag faster (see this another study).
5. Help your body recover from jet lag with some diet changes: limit sugar and alcohol, shift meal times, limit coffee in afternoons, and stay hydrated.
As with limiting blue light and adjusting sleep schedule, meal times are an important factor in mitigating jet lag’s effects. Since the SCN affects not only sleep but also our hunger levels and many other systems within our body, eating at the wrong times can signal to your body that you’re not where you actually are.
Airplane rides do try to serve the “correct” meals for the coming time zone shift, offering breakfast before a dawn landing for example. So they are helping your body eat at the new time zone’s schedule. But after arrival, I tend to crave my meals during my departure time zone’s dining hours. While it doesn’t make it easy during those first few days, I try to rigidly stick to the new time zone’s meal hours.
Further, a 2019 study identified insulin as a primary signal that helps communicate the timing of meals to the cellular clocks located across our body, aka our body clock. While scientists knew that eating at unusual times (as is often the case during shift work or jet lag) is a major cause of body clock disruption, they’ve now locked down how the body clock senses and responds to meal timing—meaning we can take some control back to help alleviate the problem. The study release notes that “paying particular attention to meal timing and light exposure is likely the best way to mitigate the adverse effects of shift-work” and jet lag.
In 2019, researchers found huge downturns in circadian rhythms and clock-related genes with high levels of glucose in the blood just prior to those events. And an interesting late January 2020 study that repairing compromised circadian clocks may even help to improve and control type 2 diabetes. The authors concluded that clock modulating medication could help diabetes and other metabolic diseases. All the more reason to pay attention to your sugar when you are actually actively changing up your body clock!
A December 2021 study investigated the connection with meal times and jet lag or shift work on insulin, and found that participants who ate during the night hours developed relative glucose intolerance, while those who ate only during the day showed no glucose changes of that manner. In addition, the study found that eating at in the night hours negatively affected pancreatic beta-cell function.
That study was surprising to me because it showed that daytime eating, even if sleeping on ‘off’ hours due to shift work, can maintain circadian alignment and prevent glucose intolerance. So shift workers ought to limit their carbohydrates and sugars eaten at night time,
How do these studies apply to jet lag? As with changing your computer screen to the new time zone, those who need to arrive in a new destination and get going ASAP as soon as they land for meetings, conferences, or the like, may benefit from a slow shift ahead of time to the “new” meal times and types, in order to self-regulate insulin before departure. However, they should not be loading up on carbs during the nighttime when they do that; if eating meals at night, lower glycemic index foods are preferable.
Speaking of airplane rides, while alcohol makes them entertaining for some of us, it doesn’t help with your body’s regulation of time zones since it dehydrates us.
Stick to water on the flight. And while you’re at it, stick to more water than usual. Dehydration, even caused by lack of water (and not, say, a cocktail at 35,000 feet), can worsen the symptoms of jet lag upon arrival.
And then there’s caffeine. In a new book about the mind-altering properties of plant-based substances, author Michael Pollan notes that,
Caffeine is not the sole cause of our sleep crisis; screens, alcohol (which is as hard on REM sleep as caffeine is on deep sleep), pharmaceuticals, work schedules, noise and light pollution, and anxiety can all play a role in undermining both the duration and quality of our sleep. But here’s what’s uniquely insidious about caffeine: the drug is not only a leading cause of our sleep deprivation; it is also the principal tool we rely on to remedy the problem. Most of the caffeine consumed today is being used to compensate for the lousy sleep that caffeine causes – which means that caffeine is helping to hide from our awareness the very problem that caffeine creates.
With a “quarter life” of caffeine usually around 12 hours, 25% of the caffeine in a cup of coffee you drank at noon will still be roaming around at midnight, which can impact the depth and length of your sleep.
Limit caffeine to AM in the target destination, and after you arrive, to help you adjust faster and better for the trip.
Are Allergies/Asthma Worse with Jet Lag or a Shifted Sleep Schedule?
Ok, this section isn’t part of my jet lag tips or advice on how to get over a shifted body clock faster. But it IS extremely fascinating so I’m including it anyhow. Each of us has something called mast cells, which are sentinels of the immune system. Mast cells are found throughout the body and mediate allergic, immune, and inflammatory reactions in it.
They can get dysfunctional and cause extreme reactions to foods, smells, and environmental triggers when they increase their numbers in a specific spot in the body by proliferation, or when they ‘degranulate’ (dump different inflammatory mediators into the body) with little provocation. When they get dysfunctional, the cells are implicated in brain injuries, neurodegeneration, neuropsychiatric disorders, stress and neuroinflammation. (Source).
Asthma or allergic rhinitis, and mast cell activation disorders have historically shown circadian bias — the symptoms worsen for many patients between midnight and morning time, when plasma histamine levels are a peak in the body. (Source) Is this why many people anecdotally feel a surge of allergy symptoms when they are jet lagged?
Recent research clarified that mast cells are also controlled by their own internal clock. This clock is regulated by the combo of a specific set of “clock genes” and environmental factors like diet, light exposure (see tips below!), hormones, and more.
A 2014 study examined the ways that circadian clocks drive the daily rhythms in IgE/mast cell-mediated allergic reactions in mice, and a 2018 study takes it even further, with a title of The Circadian Clock Drives Mast Cell Functions in Allergic Reactions. In that study, the authors conclude that the circadian clock modulates a whole slew of different of human diseases and functions, including asthma and allergies. Though they note that the cellular mechanisms behind this modulation – how exactly the cells do it – is still under investigation, mast cells are integral.
Mast cells are under the control of the SCN too, and have a circadian expression and release of their mediators (like histamine, prostaglandin, etc – more about mast cell mediators here) in response to activation. As mast cells are everywhere – in all the connective tissue and mucosal tissues of the body – they are uniquely able to affect other immune cells. This means they can also affect the immune response if things go pear-shaped in mast cell land.
Therefore, the study concludes, “disrupted mast cell clocks could impair the subsequent adaptive immune responses and trigger or fortify allergic symptoms.” So if we are really jet-lagged, it affects not just our regular clock, our immune clock, but also this mast cell clock – one that has a big impact on allergic reactions and asthma.
As there is growing evidence on the importance of the biological clock in allergic syndromes, targeting mast cell clock can be considered a valuable target of chronotherapy. For now, the precise mechanisms and/or specific roles of the mast cell-intrinsic clockwork in regulating reactions remains unclear. Either way, these studies point to yet another aspect of the body’s clock that may help someone suffering from jet lag: working on and tamping down allergic reactions with similar mindfulness to timing, to minimize the effects on the body overall.
If mast cells may be why, how do you treat mast cell dysfunction?
This is a complicated topic, and one that science is undertaking from many different angles. But for those who do want to explore this angle, stabilizing mast cells may be a good start. The following is what I have done, and DOES NOT constitute medical advice. It’s simply what I’ve found helped me.
- Taking quercetin powder to stabilize mast cells, 500mg, twice a day, with lunch and then right before bed in the new destination. The pure non-GMO powder I use here. Why quercetin? It has a potent anti-allergy response. See this study.
- Increasing vitamin C to help stabilize mast cells. I use camu-camu as my source, since it has incredibly high percentage of vitamin C in it. The brand I use here. I take 1/2 tsp, twice a day, with again the second dose being right before bed.
- Eating low histamine for a few days once arriving in a new destination. Low histamine diets vary, and there are many sites that discuss them. The Sighi lists are good, see here.
These are basic things, but not for those with an actual mast cell activation disorder (mastocytosis or mast cell activation syndrome), as those cases are far more complicated. Please see here for a much longer page about mast cell activation disorders, the immune system and traveling with allergies and reactions.
What about resetting the “mast cell clock”? Can that help?
However treatment of mast cell activity is not the same as “resetting the mast cell clock,” which is what the study itself proposes that we need to do.
Timing seems to matter, and I am curious to read what comes out of this approach.
There is some study work about giving mice steroids before bed to help reset the mast cell clock for allergic rhinitis (source), and also taking steroids at night for humans (source). The “mast cell clock” is potentially why taking those stabilizers at night helps me more than during the day. But this is speculation presently, and an interesting field of study.
As there is growing evidence on the importance of the biological clock in allergic syndromes, targeting mast cell clock can be considered a valuable target of chronotherapy. […] The biological clock is quickly becoming another lever in the field of personalized medicine, which aims to add the time factor as another dimension of therapy.
Hopefully inroads come soon for this potentially novel way to help us adjust better and feel better as we do.
Can Shifts in Sleep and Dysfunctional Body Clocks Lead to Depression?
Scientists think so! Disrupted sleep patterns can affect mental health, and scientists have studied the link between the two for decades. These days, attitudes toward depression include exploring a range of chronotherapeutics, therapies that target the body clock and circadian rhythms without the use of pharmacological drugs.
An August 2022 Nature article about mental health and the body clock also notes that,
[m]uch of the public conversation around depression casts the disease as a chemical imbalance in the brain. But mood disorders have increased with modern lifestyles. There is growing evidence that circadian-rhythm disruptions and altered light exposure (with more artificial light at night and less natural daylight during the day) that accompany those lifestyles increase the risk of depression.
Studies are underway to ascertain if resetting and rectifying the body clock can help ease symptoms of depression, especially in people who do shift work.
Take, for example, a study published in 2020 where participants started with a “normal” sleep-wake cycle, and then underwent different shifts to sleep meant to mimic the way the body clock adapts to shift work. When the sleep schedule switched, participants’ mood plummeted. It did not improve during the time that they spent on the shifted schedule.
The study concludes that “circadian misalignment underpins mood vulnerability in shift work settings”, and in combination with other research it appears that targeted resynchronization of circadian rhythms improves symptoms of mood disorders in people with mood disorders and shift work.
In addition, a September 2022 study looked at whether meal times can have an impact on mental health for shift workers. The study divided participants into two groups, with one group eating in daytime and nighttime hours, and the second group only eating during daytime hours (before 7:30pm per the chart below). The study revealed that meal timing really had an impact on the participants’ mood levels. By day 4, the day and night eaters had increased levels of depression and anxiety feelings, but no mood shifts were observed in the “daytime only” crew during their night shift.
So can we use meal time as a way to help keep our mood stable even if jet lagged or on a night shift? Possibly! Further research is underway.
Researchers also noted that individuals with a higher degree of circadian misalignment were more prone to depression- and anxiety-like mood swings.While circadian disruption may not be the sole cause of mood disorders, it still points to the conclusion that the increased risk of depression among shift workers is caused by the misalignment of the body’s internal clock with the outside world. Targeted therapies like light therapy (light boxes in the “morning” hours for the shift worker), wake therapy, and other non-pharmacological modalities—like eating in the day time!— could therefore help.
Can Shifts in Sleep Schedules Increase Nausea and GI Issues?
At this point in your reading, I feel like you already know the answer. Yes, yes there is.
I was curious about why I had a slew of gastrointestinal issues when I was most jet lagged. My stomach often felt bloated after meals, and queasy in early mornings. It turns out that there was a logical reason, one that relates to the role of circadian rhythms on the digestive tract.
Researchers at Washington University School of Medicine in St. Louis identified a type of immune cell that helps keep time in the gut, a finding they published in October 2019. These cells, called type 3 innate lymphoid cells (ILC3), keep the gut working the way it’s supposed to. And to make matters more interesting, those clock genes I wrote about near the beginning of this post? They are highly active in those ILC3s, to the point where immune molecules produced by those cells track with the activity of the clock genes.
In the October study, when researchers removed an important clock gene from mice, the animals both couldn’t produce adequate ILCs, and they couldn’t control a bacterial infection in their gut. The researchers believe that these findings help explain why disruptions to circadian rhythms are linked to gastrointestinal problems.
Marco Colonna, a senior author of the study, notes that “what we’ve found here is that circadian rhythms directly affect the function of immune cells in the gut.” He believes this could help explain some of the health issues found with people who engage in shift work, or who have jet lag or chronic sleep deprivation, such as IBS or metabolic syndrome.
To work optimally, the gut needs to be prepared for daily routines, nourishment, bacteria, and more, and this study shows that ILC3s play a critical part in making the gut run smoothly. When the researchers simulated a shift worker’s schedule in the study mice, the ILC3s did not work normally.
In addition, another 2019 study by researchers at the Champalimaud Centre for the Unknown in Lisbon discovered that an immune cell’s function is an important contributor to gut health – and that their function is directly controlled by the brain’s circadian clock. This study also studied the same ILC3 cells. The Lisbon researchers felt that their findings may at least in part explain the link between sleep patterns and gut inflammatory responses. So less protective ILC3s can lead to chronic inflammation and disease.
Thus, not only does jet lag affect the gut, but it can also affect inflammation and the gut’s ability to fend off bacterial infection — which is really important if we are traveling to a place with new bacteria, viruses, and germs. This is because it produces a less effective protective immune response when its time clock is wonky.
Additional human studies by Teng’s group showed that ILC3s isolated from the inflamed gut of patients with inflammatory bowel disease (IBD) expressed lower levels of clock proteins than ILC3 from the non-inflamed gut in the same patients. “… it has become increasingly appreciated that there are certain signatures of immune responses and therapies that exert day and night differences (termed as chrono-immunotherapy),” the Cornell University researchers continued. “Therefore, our critical finding that ILC3s in the inflamed intestine of patients with IBD exhibit altered circadian gene expression suggests that this is an important pathway in human health and disease and may hold a key for developing novel strategies to boost ILC3 responses in the context of impaired intestinal homeostasis or microbial dysbiosis.”
Scientists are now looking at targeting clock genes in ILC3 cells to address this problem. In the interim, us non-scientists can optimize our circadian rhythm shifts to keep our immune system and gut health working as normally as possible.
Airlines are now undertaking “ultra-long-haul travel,” like the October 2019 Qantas Airways direct flight from New York to Sydney, a nearly 20 hour trip. That’s the world’s longest flight, and no airline has ever completed that route without stopping.
While the flight should provide more insight into the tolls of jet lag, you don’t need to wait for that data. Use my jet lag protocol to hopefully help you ease into a new destination with less disruption to your body clocks and cells.
Further Reading on Jet Lag and How to Sleep Better
Some books that have helped me as I tried to beat jet lag, and learn more about how to sleep.
- The Rhythms Of Life: The Biological Clocks That Control the Daily Lives of Every Living Thing, by circadian neuroscientist Russell G. Foster. Rhythms of Life is a wonderful and accessible introduction to the world of daily and seasonal biological rhythms.
- Internal Time: Chronotypes, Social Jet Lag, and Why You’re So Tired, by chronobiologist Till Roenneberg. Internal Time investigates the connection and conflict between biological and social clocks and how social jet lag affects almost everyone.
- Dreamland: Adventures in the Strange Science of Sleep, by David K. Randall. The book tackles the science behind sleep, a book he was inspired to write when he started sleepwalking. In Dreamland, Randall explores the research about sleep and how it changes by gender, age, and all of the other factors that impact an activity that takes up 1/3 of our lives.
- Sleep: A Very Short Introduction, by Russell G. Foster and Steven W. Lockley. This book looks at why we sleep and how much is enough for a modern human. From sleep disorders to quality of life, the authors examine the relationship between sleep, work, and the impact of an always “on” society.
- Jet Lag: Objective Lessons, by Christopher J. Lee. Lee’s trippy take on circadian changes in the body, as seen through the lens of modern flight – “Jet lag is a momentary condition resulting from the human body and its inner clock being pitched against the time-leaping effects of modern aviation.” The book is more of a statement about the fast-tracked world we live in than the lag itself, but it’s a very worthy read.
- Why We Sleep: Unlocking the Power of Sleep and Dreams, by Matthew Walker, PhD is not a book with tips for jet lag, but like some of the others on this list goes into the science of why and how our brains do what they do during slumber. It’s also a huge bestseller. “Within the brain,” says Walker, “sleep enriches a diversity of functions, including our ability to learn, memorize, and make logical decisions. It recalibrates our emotions, restocks our immune system, fine-tunes our metabolism, and regulates our appetite. Dreaming creates a virtual reality space in which the brain melds past and present knowledge, inspiring creativity.” For anyone having trouble sleeping well, this is a great option. Link is to the updated edition from 2017. If you wanted an audio version of Walker’s research, his August 2020 podcast with Peter Attia discusses sleep and the immune system, COVID-19 and sleep, hormones, and more here.
- How Natural Supplements Can Change Circadian Gene Expression (blog post): This jet lag post discusses circadian rhythm genes and how they are foundational to health, but if you are interested in a gene-based discussion instead of a habit one, see Debbie Moon’s post about supplements that can alter the body clock. She also runs through the main genes in the core circadian clock, such as CLOCK, BMAL1, CRY1/2, and PER1/2, and adds secondary genes that affect a different regulatory loop. If you’re into biohacking and genetics, this is a good post to read.
- At Day’s Close: A History of Nighttime, by Roger Ekirch. This is a departure from the prior recommendations, but is very entertaining and informative. Ekirch goes back to the preindustrial time, explaining how we lived at night then when no electricity illuminated our lives. Extra risks, extra superstitions, and it was often women who did the brunt of the nighttime work. Fascinating read.
Jet Lag is a Reality I’ll Take, Especially When I’ve Learned to Beat It Faster.
Ultimately, jet lag isn’t that bad. It’s a temporary state, and we know it. It’s a mindless torture of teeny chunks of time, one that allows us to let go of life’s reigns a little bit, and sink into disorder.
The tips I’ve written about here have helped me beat jet lag’s effects on my life, but when I am in the throes of it I try to enjoy it also. As Pico Iyer said in his New York Times piece on the subject:
Fourteen hours later, I’m on a different continent and hardly able to imagine the life, the home, I left this morning. It’s as if I have switched into another language — a parallel plane — and none of the feelings that were so real to me this morning can carry through to it. It’s not that I don’t want to hear them; it’s that they seem to belong now to a person I no longer am.
There is something gloriously discombobulating about emerging from a long flight into the fog of a new place. So even if the impacts of jet lag lessen but never go away fully, there are far worse states of mind to inhabit.