Jet lag from eastward-to-westward travel is generally the easier direction to recover from, but it still takes most people 3 to 7 days to fully resynchronize. The good news is that your body’s internal clock naturally cooperates with westward adjustment, and a few targeted strategies can speed the process significantly.
Why Westward Jet Lag Is Easier
Your internal body clock doesn’t run on a precise 24-hour cycle. It actually runs slightly longer, which means your body naturally drifts toward a later schedule when left to its own devices. When you fly west, the local time shifts earlier: if you leave New York at noon, you land in Honolulu and it’s still morning. Your body needs to push its sleep-wake cycle later to match the new time zone, and that “phase delay” aligns with the direction your clock already wants to drift.
This is why westward recovery takes roughly 3 to 7 days, while eastward travel (which forces you to shift earlier, against your natural drift) can take 5 to 14 days. An analysis of over 20 years of Major League Baseball data confirmed this pattern: player performance suffered more after eastward flights than westward ones. The asymmetry is real and measurable, but crossing enough time zones westward will still leave you groggy, unfocused, and wide awake at 3 a.m.
Use Evening Light, Avoid Morning Light
Light is the single most powerful tool for resetting your body clock. The principle is straightforward: bright light in the evening pushes your internal clock later, which is exactly what westward travel demands. Bright light in the early morning does the opposite, pulling your clock earlier and working against your adjustment.
For your first few days after landing, get as much outdoor light as you can in the late afternoon and evening. Even 30 to 60 minutes of natural daylight before sunset helps. At the same time, protect yourself from bright light in the early morning hours. If you wake up before dawn at your destination (because your body thinks it’s mid-morning back home), keep the lights dim, wear dark sunglasses if you go outside, and avoid screens at full brightness. The CDC recommends this same approach for westward travelers: close the window shade and shield your eyes during the hours that correspond to early morning at your origin.
Once you’ve shifted by a few hours and your wake time starts aligning with local morning, you can relax this rule and resume normal light exposure throughout the day.
Time Your Meals to the New Zone
Eating on your destination’s schedule is one of the simplest adjustments you can make, and it works on a biological level. When you eat at an unusual time, the hormonal signals triggered by digestion, including insulin and other gut hormones, act on internal clocks in your liver and digestive organs. Over a few days, these peripheral clocks shift to anticipate food at the new time. This won’t single-handedly cure jet lag, but it reinforces every other signal you’re giving your body about what time it is.
In practical terms: eat dinner at the local dinner hour even if you’re not hungry, and avoid a big meal in the middle of the night just because your stomach thinks it’s lunchtime back home. If you’re genuinely hungry at odd hours, a small snack is fine, but save your main meals for local mealtimes.
Exercise in the Late Afternoon or Evening
Physical activity has its own ability to shift your body clock, and the timing matters. Exercise in the hours before your body’s temperature minimum (which falls roughly 2 to 4 hours before your habitual wake time) pushes the clock later. For most westward travelers, this translates to working out in the late afternoon or evening at your destination during the first few days.
The shift from exercise is modest compared to light exposure, and conveniently, the best times for exercise overlap with the best times for evening light. A late-afternoon jog, walk, or gym session outdoors combines both signals. You don’t need intense training. Moderate activity for 30 to 60 minutes is enough to contribute to the adjustment.
Melatonin Timing for Westward Travel
Melatonin can help, but the timing for westward travel is counterintuitive. Unlike eastward trips where you take melatonin at your new bedtime, westward travelers benefit from taking melatonin in the morning at the destination. This sounds odd, but morning melatonin sends a “nighttime” signal that helps push your clock later, reinforcing the phase delay you need.
Doses as small as 0.5 milligrams appear to be as effective as 5 milligrams for shifting the clock, though higher doses may help more with sleep itself. If you’re primarily using melatonin to fall asleep at a reasonable local hour, take it about 30 minutes before your intended bedtime. But for clock-shifting purposes during westward adjustment, the morning dose is the strategic choice.
Manage Caffeine and Naps Carefully
After flying west, you’ll likely feel sharp in the local morning (when your body thinks it’s afternoon) and crash hard by early evening. Caffeine can bridge the gap, but timing matters. Avoid caffeine in the early morning at your destination. Your body is already alert then because of your old schedule, and early caffeine can interfere with the later sleep onset you’re trying to establish. Instead, use caffeine strategically in the mid-to-late afternoon if you need to stay awake through the local evening. Cut off caffeine at least 6 to 8 hours before your target bedtime.
Napping is tempting when you hit that wall, and short naps are fine. The CDC recommends capping naps at 15 to 20 minutes. Anything longer risks dropping you into deeper sleep stages, leaving you groggy and making it harder to fall asleep at the local bedtime. If possible, avoid napping after mid-afternoon, since even a short nap late in the day can sabotage your evening sleep.
A Day-by-Day Approach
Your body can typically shift its clock by about 1 to 1.5 hours per day in the westward direction. If you’ve crossed five time zones, expect roughly 3 to 5 days before you feel fully normal. Here’s what a practical recovery looks like:
- Day 1: You’ll wake very early and feel sleepy by late afternoon. Stay up as close to the local bedtime as you can, using evening light and activity. Keep lights dim if you’re awake before dawn.
- Days 2 to 3: Your wake time starts shifting later. Continue prioritizing evening light and avoiding early morning brightness. Eat all meals on local time.
- Days 4 to 5: Most travelers crossing 5 or fewer zones feel largely adjusted. You may still wake slightly early but can fall asleep at a normal hour.
- Days 6 to 7: For larger crossings (8 or more zones), full adjustment may take this long. Maintain consistent sleep and wake times even on weekends.
Start Shifting Before You Fly
If your trip is planned in advance, you can get a head start by gradually pushing your schedule later in the days before departure. Go to bed 30 to 60 minutes later each night, and wake up correspondingly later if your schedule allows. Even shifting by 2 hours before a 5-zone westward trip shaves a meaningful chunk off your recovery. On the flight itself, set your watch to destination time, time any onboard naps to align with nighttime at your destination, and avoid bright light during hours that correspond to your destination’s nighttime.