We’ve all had the familiar experience of feeling groggy, irritable, and maybe even ill, when traveling across multiple time zones. While jet lag can be common for any traveler, sleep experts say it’s mostly temporary and can be alleviated through good sleep habits and some extra travel preparation.
Even traveling just a few time zones can impact circadian rhythm, a 24-hour sleep-wake pattern internally programmed in the body and brain that has evolved over time to ensure that humans are optimally adapted to the external environment, mainly, the light and dark patterns that come from the Earth's rotation.
“This pattern is programmed into our genes and those genes have been found in virtually all tissues of the body,” says sleep specialist Jessica Camacho, MD, assistant professor of internal medicine at the University of Colorado School of Medicine. “At this point in science, we know that circadian rhythm not only regulates sleep and wake, but it also serves an important role in regulating many other vital body functions throughout the body, including metabolism, hormone release, and immune function.”
The effects of jet lag
Jet lag is a group of symptoms that occur after a person travels rapidly across multiple time zones — particularly eastward —resulting in a mismatch between the body's internal clock and the new time zone.
Travelers may experience trouble falling asleep, fragmented sleep, poor quality sleep, or difficulty staying asleep through the night. Symptoms of jet lag also include impaired concentration, focus, and alertness.
“We also know that jet lag can dampen reflexes and impair your decision-making skills,” Camacho says. “You may even feel physically ill, such as an upset stomach.”
The good news is that these symptoms fade over a few days.
“For the average person, jetlag will set in in one or two days after you arrive at your destination and how long it lasts and how severe the symptoms are will depend on how many time zones you travel,” Camacho says.
Similar symptoms can arise for shift workers who take on schedules opposite of the body’s circadian rhythm. Prolonged sleep disruption may cause more intense symptoms and affect health further, which may require expert help to manage.
Preparing for takeoff (and bedtime)
Alleviating jet lag symptoms starts with prevention.
“You want to make sure that you're keeping healthy habits to begin with, especially regarding sleep. We refer to healthy sleep habits as sleep hygiene,” Camacho explains. “It's really about getting the optimal seven to nine hours of sleep per night, keeping a consistent bedtime and wake time, and avoiding electronic screens close to bedtime. Moderating your caffeine and alcohol use, getting good exercise, and staying hydrated can also impact your sleep hygiene.”
That foundation can go a long way, but taking preventative measures before a trip may help too.
“Shifting your natural sleep-wake cycle a little bit ahead of travel can make it easier after arriving at your destination,” Camacho says. “For eastward travel, you can do this by adjusting your bedtime about one hour earlier each day for the three days before the trip. Focusing on bright light exposure first thing in the morning on those days can also help adjust the sleep cycle.”
There’s also some evidence, she says, that taking an over-the-counter melatonin supplement those few days before travel can help. Melatonin is a naturally occurring hormone that’s released when circadian rhythms start to set in later in the day and helps to ready the body for rest.
“A nice low dose of melatonin at bedtime for those three days before the trip has been shown to be helpful for alleviating jetlag symptoms,” Camacho says. “We're talking 0.5 to 5 milligrams, something pretty small. Bigger doses may actually induce feelings of grogginess. When you get to your destination, you may want to continue these small doses at bedtime to help adjust.”
Frequent flyers may notice more jet lag symptoms, sometimes even impacting their daily lives and work. In these cases, Camacho says it’s recommended to consult a doctor to determine the best course of action.
“Any individual who is traveling a lot, or has experienced pretty significant jetlag that persists, can begin to develop a secondary sleep disorder, such as chronic insomnia,” she says. “If the symptoms persist, and they aren't temporary, and they’re negatively impacting you, it could be a sign that there could be something else going on.”
A medical evaluation may be necessary so that sleep issues don’t further impact health.
“Sleep makes up one-third of our lives, yet it’s often overlooked as a big component of health, and it’s undervalued in terms of what it can do for so many bodily systems,” Camacho says. “By practicing good sleep hygiene and being mindful about our routines, jet lag can be easy to manage.”
April 14, 2024