Abstract
Modern air travel has revolutionized global connectivity, allowing millions of passengers to traverse continents safely and efficiently every day. Air travel, for the vast majority of us, is ultimately about the destination and the meaningful connections it enables. Because aviation crews operate a highly synchronized system across multiple time zones, the real challenge begins after landing as our bodies adapt. Even with smooth flights, crossing time zones can temporarily leave travelers feeling physically tired and momentarily disoriented.
Your Body Lands in Portugal, But Your Circadian Rhythm Remains in California
First coined in a Los Angeles Times article 1 in the 1960s, jet lag is a condition unique to traveling across time zones. Categorized as a circadian rhythm sleep-wake disorder, jet lag occurs when a person’s internal clock does not match the local day-night cycle. 2 As the original article describes it, “jets travel so fast they leave your body rhythms behind.”
Normally, a person’s internal clock (also called circadian rhythm) promotes alertness during the day and sleep at night, in addition to influencing other biological processes including mood, performance, hormone release, metabolism, and immune function. 2 This clock relies on the external 24-hour light-dark cycle to promote good physical and mental health. Because circadian rhythm is regulated by light exposure, even a 1 hour shift can disrupt our systems that manage appetite, mood, and sleep. 3 So when we travel across time zones quickly, like we do with air travel, our internal clocks can’t adjust fast enough, and we may experience jet lag symptoms.
Increasing international travel means that millions of people experience travel-related sleep disruption each year. Research estimates that 68 percent of international business travelers experience negative symptoms on a regular basis, and a staggering 100 million people are believed to experience jet lag every year. 4 The rise of remote work, “bleisure” travel, and post-pandemic increases in long-haul tourism have further normalized rapid transitions across multiple time zones, increasing exposure to circadian disruption among both business and leisure travelers.
While most travelers are willing to cope with occasional jet lag symptoms, the condition goes beyond just causing travelers to be “a little tired.” In fact, there are significant health and economic impacts associated with it.
The most obvious physical issue is sleep disturbance. Travelers may find it difficult to fall asleep at the appropriate time at their destination, or they may have difficulty staying awake during the day to participate in the activities they planned. However, while low energy while adjusting to a new sleep-wake cycle can be inconvenient, it is not necessarily the most troublesome symptom.
In addition to sleep disturbance and drowsiness, jet lag can have an impact on things like hunger and digestion. Gastrointestinal motility follows the body’s circadian rhythm, being active during the day and more dormant at night while the body is at rest. When the sleep-wake rhythms are disrupted by rapid travel between time zones, the bowel can be disrupted too, contributing to digestive dysregulation and exacerbation of conditions such as irritable bowel syndrome. 5
In addition, research shows that travelers experiencing sleep disruption for just two to three nights can have a 30 percent reduction in natural killer cell activity, a key component of the immune system. This could mean that travelers with more severe jet lag symptoms may be temporarily more susceptible to common, minor travel illnesses, such as mild upper respiratory tract infections, during or immediately following their trip.
Reports also suggest that jet lag can affect a traveler’s mental health, causing symptoms like low mood, irritability, difficulty concentrating, and malaise. One study found that as many as 46 percent of people notice a dip in their overall mental health as a result of missing sleep, a common outcome of long-distance air travel. 6 Jet lag can also lead travelers to rely heavily on self-medication strategies, such as the poorly timed use of alcohol, over-the-counter sleep aids, or caffeine to artificially manage sleep and wakefulness. 7
In fact, mood disorders and circadian rhythm disruption can feed upon each other, worsening both. 4 Mood disorders have been associated with disrupted circadian responses (e.g., sleep and cortisol secretion), and disruption of circadian rhythms via jet lag, night-shift work, or exposure to artificial light at night has been shown to precipitate or exacerbate emotional symptoms in susceptible individuals.
Taking all this into account, it is not surprising that jet lag has a significant impact on consumer behavior when it comes to travel. One survey found that 23 percent of people in the United States would put off taking a long-haul trip to avoid jet lag, however, most were willing to deal with the symptoms due to Fear of Missing Out. 4 Despite that, 42 percent did admit that they found symptoms of jet lag to be a big challenge.
These symptoms do affect how people travel. About one-third of travelers have skipped or rescheduled plans while traveling just to catch up on sleep, and nearly half claim poor sleep has negatively impacted their trip enjoyment or led to an argument. 8 Most travelers (79 percent) return from vacation feeling like they need another one just to recover, thanks in part to jet lag.
The hospitality and health industries have taken note of the fact that 38 percent of travelers have intentionally chosen hotels or rentals based on sleep-related features and one in five would pay more for a hotel room specifically designed for better sleep. 8 There is also the recent boom of so-called “jet lag therapy”—a variety of techniques and preventative measures used to combat the condition. Driven by the advancement of technology and tools within sleep management, the market reached $457.6 million in 2025. 9 Spending on jet lag prevention and treatment is expected to grow at a rate of 3.58 percent annually from 2026 through 2034, seeing the value increase substantially to $633.9 million in less than a decade.
One encouraging piece of data is that sleep duration appears to bounce back fairly quickly. The Sleep Foundation 2 states that the circadian clock takes ∼1–1.5 days to adapt per time zone crossed, while a recent study of Oura ring data 10 from 1.5 million nights of sleep in over 57,000 participants confirmed that the amount of sleep someone gets every night rebounds to within 12 minutes of baseline within just 2 days of returning home. This is great news for those who have the flexibility to build in a recovery weekend after a long trip.
On the other hand, the same large-scale sleep-tracking study revealed that while sleep duration recovers quickly, sleep timing and quality of sleep can take significantly longer to bounce back. On average, bedtime and wake time remained shifted even after 15 days—though these are often subtle trends captured by sensitive biometric sensors rather than prolonged insomnia—and travelers experienced less restorative sleep for several nights. 11
Landing in Sync: Digital Tools for Travel Fatigue
With all of this in mind, there are ways to combat the physical and mental symptoms that define jet lag, some of which are common sense if you know the science. Itinerary details, sleep schedules, stress management, light exposure, and use or abstinence from certain substances and supplements can all mediate jet lag severity.
Symptom prevention starts before the trip with building rest days into the itinerary and booking flights that will disrupt your sleep schedule the least. Keeping your body in top form by moving, hydrating, and avoiding caffeine and alcohol can also help. Upon arrival, increase natural daylight exposure, or have melatonin or other sleep aids on hand to ensure that you can drift off to sleep at the right time for your current time zone. At the same time, the very technologies travelers rely upon during trips—smartphones, streaming platforms, and late-night digital engagement—may inadvertently prolong circadian disruption through continued exposure to artificial light and cognitive stimulation.
Beyond these analog fixes, digital tools offer a growing range of solutions. The most abundant of these is jet lag prevention apps, downloadable programs that offer light, sleep, meal, and activity advice customized to a user’s specific travel plans and daily habits. 12 A recent report found that 69 percent of travelers were either already using these kinds of apps or intended to start using them in the future. 4 The most complex of these offer filters for caffeine or melatonin use, vacation sleep schedules, and activity level upon arrival. Examples include trip-specific scheduling applications and wearable-integrated platforms that provide individualized recommendations based on travel itinerary, light exposure, and biometric data, including platforms such as Timeshifter or Garmin’s Jet Lag Adviser.13,14
Other technology-assisted tools involve harnessing the strong influence light has over the circadian rhythm. Properly timed periods of both daylight and darkness can help synchronize a traveler’s body with a new time zone. While on the flight (or soon after arrival at a destination), some travelers use blue light blocking glasses before sleep to avoid artificial light, naturally boosting melatonin production and telling the body that it is nighttime.
Another option is to use an artificial natural light box. Some light-based sleep technologies use low-intensity timed light exposure during sleep to help shift circadian timing prior to travel. 13 The idea is that these bursts of light can help shift a person’s internal clock up to 3–4 hours a night. As wearable sensors, sleep analytics, and artificial intelligence continue to evolve, future systems may provide increasingly individualized circadian recommendations based on real-time behavioral, physiological, and environmental data.
Finally, if access to nature at a particular destination is limited, travelers can combat mood swings with virtual and mixed reality immersive nature environments that allow them to spend time “outdoors” even when the time zone does not permit. 3
As long-distance air travel continues to be an essential part of modern life, understanding and managing the effects of jet lag will be crucial. The hospitality industry, health professionals, and technology developers have already responded with a number of targeted solutions: from sleep-optimized itineraries to innovative apps and wearable devices. By blending analog and digital approaches, travelers can minimize the negative impact of jet lag; supporting better sleep, and enhancing the overall travel experience, and enjoying healthier global adventures.
Brenda K. Wiederhold
Editor-in-Chief