We’ve all been there or at least know someone who has. You plan a trip, map out every detail, arrive at your destination on time, and spend the first few days staring at the ceiling of your hotel room.
Jet lag – when your body thinks it’s early evening after a long flight from Los Angeles to Boston, but it’s actually after midnight – can wreak havoc on travelers. Rather than enjoying your trip the first couple of days, you stay up past your usual bedtime, feel drowsy during the day, and lack focus.
We’ll explore below what jet lag means, the cause, symptoms, and how you can prevent it, and we’ll even throw in some helpful tips on ways to avoid it.
Did You Know: Jet lag can occur anytime two or more time zones are crossed.
In this article, we'll discuss the following:
Jet lag is also referred to as circadian desynchrony.  Our body has its own internal clock (or circadian rhythms) that tells us when it’s time to awaken and go to sleep.  It’s essentially a mismatch between this internal body clock with external environmental cues (daytime and nighttime in particular). 
Jet lag causes the mistaken need to stay wide awake and active because of two main problems:
In short, the normal clockwork and hormones (mainly melatonin) that regulate wake/sleep cycles tend to desynchronize due to travel through time zones.  
Find out how our sleep systems and products improve sleep quality through precise temperature regulation, ranging from 55-115º, to enhance your deep sleep and wake up rested.
Feeling like you just traveled across the globe but haven’t left your couch? Check out our article on social jet lag to see how your weekend habits could be the cause.
Jet lag is often mistaken for travel fatigue. It can be caused by a demanding and hectic schedule, stress from being away from family, or lack of sleep. Also, It occurs with any method of travel, such as cars or trains. Symptoms of travel fatigue can include headaches and tiredness because of the physical toils of traveling.
Did You Know: Travel fatigue doesn't involve circadian rhythm disruption.
Jet lag, as defined above, is related to the changes in time zones and how changes affect the circadian rhythm. In scientific terms, this intricate system is controlled by the suprachiasmatic nucleus (SCN), located deep within our brains in the hypothalamus. The SCN is situated near the visual system to take cues from sunlight and darkness. This allows our bodies to react by waking up or falling asleep.
Sleep Study: Travel Fatigue and Jet Lag
Jet lag is quite common. It's estimated that 60% to 70% of frequent travelers have experienced symptoms. The elderly have a harder time adapting to destination time zones than younger people.
Researchers agree that west-to-east plane travel leads to more serious symptoms than going from east to west. The greater number of time zones traveled may lead to more intense bouts of jet lag.
When traveling from north to south or vice versa, jet lag is not an issue because there is no crossing of time zones. Therefore, people experiencing disturbed sleep or tiredness are more likely to have travel fatigue.
It's been reported that traveling east has more issues than people traveling the same number of time zones west. The concept is that it's a more significant challenge to advance rather than delay the body's internal clock. Most people have an endogenous circadian rhythm longer than 24 hours, so prolonging a day is less problematic than shortening it.
The common question is, what does jet lag feel like? If you're not too familiar with it, you may experience one or more of the following symptoms of jet lag, including:
The above symptoms appear after extended flights to different time zones because of disrupting your circadian rhythm. It affects how and when your body produces hormones, which can impact your sleep and other bodily processes. Fortunately, the symptoms improve steadily as the body gets used to the new time zone. 
Did You Know: 60-70% of long-haul travelers will experience some form of jet lag symptoms.
It’s possible to use light, temperature, meals, and exercise to get accustomed to the new environment. These are called zeitgebers, which means "time givers" in German. They are particularly helpful when traveling from west to east when losing time.
The Federal Aviation Administration (FAA) describes zeitgebers as any external cue that resets the body’s internal clock, essentially getting the sleep-wake circadian rhythm back on track. 
The following zeitgebers can be instrumental in resetting sleep signals: 
Bright light is an incredibly important time giver. Once you get to your destination, get as much natural light as possible if you need to stay awake. Doing so helps keep the body from producing melatonin, a natural sleep hormone.
If you arrive at your destination when it's dark outside, try to utilize artificial light from the overhead lights and lamps. Yet try to avoid the flashing lights of your cellphone or laptop.
There’s extensive scientific evidence that transitioning to restful sleep is much easier when core body temperature (CBT) drops. Sleep experts recommend adjusting the room temperature to between 65- and 72- degrees Fahrenheit.
Read More: Why Do I Get So Hot When I Sleep
Any exercise, such as brisk walking, stretching, and calisthenics, is a perfect way to reset your circadian rhythm. If exercise is part of your at-home routine (which we highly recommend), try to exercise well before bedtime and at the same time of the day.
Your eating schedule and meals have a definite effect on jet lag. Remember that beverage and food choices affect insulin levels, which can impair the sleep cycle.
How long will jet lag last depends on different factors. A more extended recovery period is required when traveling from west to east. Jet lag can last anywhere from four to five days. Some specialists say that traveling over just one or two time zones is minimally problematic.
A good rule of thumb is about one day per time zone. Other factors to consider are the utilization of treatments and pre-flight strategies
Individuals who encounter jet lag feel better a few days after arriving at their destination. But it can take up to one week for some people to feel back to themselves.
It's recommended to drink lots of water! The dry air of the airplane cabin can cause dehydration. Dehydration can be detrimental to the circadian system in addition to overall health.
If you have a watch or packed a travel clock, adjust it to your destination upon takeoff. It can help you mentally adjust to your new destination sleep cycle.
Explore in-flight sleep aids such as noise-canceling headphones and weighted blankets.
Read More: Shift Work, Shift-Work Disorder, and Jet Lag
Extensive research and the expert opinions of health professionals emphasize that although jet lag can be a troublesome feature of in-flight travel, it does not need to interfere with our plans for success, productivity, and enjoyment. You can take many steps to avoid jet lag and its challenges.
 Choy, M., Salbu, R.L. (2011). Jet lag: P&T, 36(4). 221-231. View Study
 Mayo Clinic. (n.d.). Jet lag disorder. Mayo Clinic. [Blog Post]. View Resource
 Choy, M., Salbu, R.L. (2011). P&T, 36(4). 221-231. View Study
 Choy, M., Salbu, R.L. (2011). Jet lag: Current and potential therapies. P&T, 36(4). 221-231. View Resource
 Caliandro R, Streng AA, van Kerkhof LWM, van der Horst GTJ, Chaves I. Social Jetlag and Related Risks for Human Health: A Timely Review. Nutrients. 2021 Dec 18;13(12):4543. doi: 10.3390/nu13124543. PMID: 34960096; PMCID: PMC8707256.
 Schwab, R. J. (2020, June). Circadian Rhythm Sleep Disorders. Merck Manual Consumer Version. View Resource
 Choy, M., Salbu, R.L. (2011). Jet lag: Current and potential therapies. P&T, 36(4). 221-231. View Resource .