Contributed by Kendra Dombrowski
Your body runs on a built-in clock that helps keep everything on schedule: when you feel sleepy or alert, hungry or focused, and even how your digestion and metabolism work. This 24-hour cycle is called your circadian rhythm.
When you fly across several time zones, that internal clock can’t reset fast enough. It stays synced to the time at home while the local time has already shifted–this mismatch is what causes jet lag. For example, if you fly from LA to NYC, your body still thinks it’s three hours earlier. This can make it harder to fall asleep, leave you feeling tired during the day, make it tough to focus, and even disrupt your digestion. Because most people can only adjust by about one hour per day, jet lag can linger for days.
The good news: you can help your body adjust more quickly. By understanding the daily cues like light, meal timing, exercise, and temperature that set your internal clock, you can shift your rhythm faster and reduce the effects of jet lag.
The 5 best cues to help shift your internal clock to the correct timezone when traveling
#1 Light is the primary reset signal to your brain
Light is the strongest signal to your brain (ref). Viewing light at the right time(s) of day can help your body adjust to your new time zone faster.
- When you fly east (ex: from LA to NYC), your challenge is falling asleep earlier than your body wants to. Getting bright light within 1-2 hours of waking at your new destination helps move your body clock earlier (ref), while avoiding bright light at night keeps it from drifting later (ref).
- When you fly west (ex: from NYC to LA), evening light helps you stay awake longer, and avoiding bright light early in the morning keeps your clock from shifting too early. Try to get at least 30-60 minutes of bright light in the late afternoon or early evening, and keep the lights dim for the first 1–2 hours after waking in the morning.
#2 Exercise tells your body when it’s time to be active
Exercise can also help adjust your body clock to your new time zone, though it’s not as powerful as light. But when used at the right time it can still speed up your clock’s adjustment.
- If you fly east, light-to-moderate exercise in the morning within 1-3 hours after waking up helps your body adjust to an earlier schedule (ref).
- If you fly west, moderate exercise 1-3 hours before bedtime can help you stay awake longer. Keep in mind that intense workouts within 1 hour of bedtime can make it harder to fall asleep, so timing and intensity matter (ref).
#3 Meal timing reinforce your rhythm
Your body’s clock also responds to when you eat. Aligning your meals with your new time zone can help your digestion and metabolism align with your new time zone.
Regardless of your travel direction, aligning your meal schedule with the local light schedule can help you recover from jet lag up to 3 days faster (ref). Additionally, having a substantial meal in the morning and a light dinner in the evening can further accelerate alignment.
- When you’re traveling east, have a solid breakfast in the local morning (ref), even if it feels a bit early for you. Keep dinner lighter and earlier, leaving at least 1-3 hours between dinner and bedtime so your body can wind down (ref).
- When you’re flying west, eat a moderate breakfast and lunch on the local timezone and have a normal‑sized dinner, as long as it doesn’t push too close to bedtime or cause discomfort.
#4 Supplements can help accelerate travel recovery
Supplements can help by keeping you alert (caffeine), helping you fall asleep (melatonin), and reducing stress (phosphatidylserine).
- Caffeine is a powerful timing signal for your body, though it should be timed carefully to boost circadian alignment without impacting your sleep.
- If traveling east: Avoid caffeine at least 6 hours before your target bedtime (ref). Studies show that consuming caffeine too close to bedtime can significantly delay your internal body clock, which would be counterproductive to your jet lag recovery (ref).
- If traveling west: Consume 200 mg of caffeine every ~4 hours throughout the morning and early afternoon to help boost alertness during the day and help reinforce your new schedule (ref). Make sure to stop taking caffeine after 4 PM in the local timezone.
- Melatonin is a hormone your body naturally releases in the evening to signal that it is time to sleep. Melatonin supplementation during travel has been well studied and is considered one of the most reliable ways to reduce jet lag. Doses ranging from 0.5 to 5 mg are effective, with the strongest benefits seen when taken after eastbound travel, since your body needs to fall asleep earlier than usual. In randomized controlled trials on travelers who took melatonin before & after long-haul flights:
- Compared to taking a placebo pill, travelers who took melatonin reported that jet lag felt up to 37% less severe (ref), established a normal sleep pattern up to 31% faster (ref), and recovered from daytime fatigue in up to 35% fewer days (ref), and reported reaching normal energy levels up to 31% faster (ref)
- Travel also raises cortisol, the body’s primary stress hormone. High cortisol at night makes sleep lighter and more broken, which slows adjustment to a new time zone. Supplementing with phosphatidylserine helps lower cortisol, leading to fewer awakenings, deeper sleep, and a smoother transition to a new schedule. Most people respond well to doses between 400 and 600 mg. In randomized controlled trials, phosphatidylserine users experienced up to a 20% reduction in cortisol spike severity after stress vs placebo (ref).
If you’re interested in a supplement that combines both of these compounds, you can try Eight Sleep’s Jet Lag Supplement which combines 3 mg of immediate-release melatonin to shift your clock earlier, along with 600 mg PS to calm stress. Together, the Jet Lag formula addresses both the timing and the physiological friction that prolongs the effects of jet lag.
#5 Strategic Napping Can Help, But Timing Is Key
No matter which direction you travel, you might feel groggy at a certain point in the day, and a short nap can help you stay alert. Short naps, especially for 20-30 minutes in the early afternoon (before 3 PM in the local timezone), can boost alertness, mood, and cognitive performance (ref, ref). Keeping these naps brief is key to avoiding entering deep sleep and waking up groggy, which can interfere with your ability to fall asleep at your bedtime.
Putting It All Together
Jet lag is hard to escape when traveling multiple time zones, but you can try to control the timing of your light exposure, exercise, meals, naps, and supplements to help shorten the number of days your body takes to adjust. Here’s the practical, traveler-friendly protocol:
If you’re flying east, your goal is to shift your internal clock earlier.
Morning
- Get bright sunlight within 30 minutes to 1 hour of waking
- Do light to moderate exercise 1-3 hours after waking
- Eat a substantial breakfast aligned with the local timezone
- Stop taking caffeine at least 6 hours before your target bedtime
Midday
- Optional 20-30 min nap before 3 PM (if needed)
Evening
- Eat a lighter dinner at least 2-3 hours before your target bedtime
- Avoid bright light 2-3 hours before your target bedtime
- Take melatonin + phosphatidylserine 1-3 hours before target bedtime
If you’re flying west, your goal is to shift your internal clock later.
Morning
- Keep lights dim for the first 1-2 hours after waking
- Eat breakfast at a normal local time
Afternoon
- Get bright light for 30-60 min in the late afternoon or early evening
- Do moderate exercise 1-3 hours before bedtime
- Can consume caffeine up to a few hours before target bedtime
Evening
- Eat your largest meal earlier in the day, lighter dinner at night
- Avoid alcohol as that can sometimes make you fall asleep faster- the opposite of your goal when traveling westward.
