A Sleep Researcher Reveals the Hidden Secrets to Overcoming Jet Lag
The temporary full-body hangover affects every part of your body.
Jet lag is one of the worst parts of travel. It can steal precious hours from long-awaited exotic vacations and make the return to normal life even more difficult. However, understanding how the most primordial parts of our mind and body regulate themselves can help ease the discomfort of this phenomenon.
The temporary full-body hangover affects every part of your body, starting with your central circadian clock. This “clock” is actually a small cluster of neurons in the brain’s suprachiasmatic nucleus within the hypothalamus, which helps us maintain homeostasis. The cycle, which runs on a nearly 24-hour rotation, doesn’t depend on external cues. A pioneering 1965 paper demonstrated this principle in groups of people who lived in bunkers for three to four weeks without any hints about time, and a subject’s average biological clock reset every 25 hours.
Your heart, liver, stomach, glands, and other organs all keep meticulous time with each other, too, synchronized under the central circadian clock. Elucidating the internal processes through which these all work earned three scientists a Nobel Prize in 2017. Jet lag throws these clocks and their corresponding operations off when your internal timer is out of sync with the external timers you’re living by, says Jamie Zeitzer, professor of sleep medicine at Stanford University.
With these systems out of whack, any jetlagged person might feel fatigue, indigestion, and insomnia, Zeitzer says. He also notes they may have a temporarily weakened immune system.
Nevertheless, whether you’ve just arrived in a new timezone or returned to your home base, there are things you can do to help your body readjust. “There are certain things that people do as a matter of behavior that helps these other clocks realign much more rapidly,” Zeitzer says.
Go outside in the morning
Light is your body’s most important external time cue. If your central clock registers light when it expects dark, a neurological rooster will begin cock-a-doodling to the rest of your body clocks, signaling that it’s time to start the day when they’re not even close to ready.
A solid realignment tip, Zeitzer says, is to walk outside first thing in the morning for a double benefit of bright light to realign the wider circadian system and to increase your heart rate to sync your heart.
If you find yourself unable to sleep at 2 am, Zeitzer does not recommend turning on the lights, as that will send your central clock spiraling. Staying up later, he says, is easier than trying to make yourself go to sleep. He also recommends melatonin, which can hasten the time it takes to fall asleep.
Food is another potent time signal for your gut. Even if you’re not a breakfast person, having the first meal of the day can do wonders for realigning your chronobiology. A 2019 study analyzed more than 1100 people on how meal timing factored into jag lag. It found that not only was a regularly timed breakfast crucial for maintaining a healthy weight, but irregular breakfasts triggered misalignment. This principle carries over to other meals, which means that setting a lunch and dinner time will help your body adjust.
What you put in your body can also set you up for an energized day. If you are a coffee drinker, this might be a good time to use that caffeine buzz, Zeitzer says. He also advises against drinking alcohol, which can further disrupt sleep.
Exercise invigorates the body and heart. If you exercise regularly, a workout at your regular time of day, wherever you are, will help your body acclimate much more rapidly.
“You are increasing your heart rate, and that's good for realigning your clock in your heart,” Zeitzer says. Continuing to get regular physical activity when you’re traveling comes with the added benefit of keeping your immune system robust. Studies have established a strong link between regular movement and strong immunity.
As a rule, Zeitzer says, each timezone crossed requires one adjustment day per hour. Traveling 14 timezones, for example, takes 14 days to fully adjust to. We know this, he says, from a combination of field studies and controlled lab research.
Zeitzer’s personal experience with jet lag illustrates its toll. His longest flight, he says, was over 14 timezones to Asia. “I handled it okay,” he says, but “about five days in, I crashed, and I slept most of the day,” which he still considers a win since he operated on enough sleep the first five days. Ultimately, jet lag requires patience, listening to your body, and the willpower to sometimes not give in to the inner tantrum because your brain is so confused about why the sun is up in the middle of the night.
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