The symptoms of jet lag result from two things: the sleep deprivation and fatigue that come with long stints in a cramped seat, and the misalignment of your body clock with the local time zone, says physician Vivek Jain, medical director of the George Washington University Hospital Center for Sleep Disorders.
Jet lag’s severity depends on several factors, the most obvious being how many time zones you crossed. But which direction you traveled matters, too. Turns out, it’s not my imagination: Going east really does produce worse jet lag.
Traveling west is easier
Your body clock has an innate tendency to run slightly longer than 24 hours, Jain says. Each morning, your body compensates for this slight discrepancy by contracting your internal clock to synchronize with the 24-hour sun cycle. When you travel west, you gain several hours, so your day is extended and your body gets the extra time it naturally wants. But when you travel east, your day is shortened; that makes it harder to adjust, Jain says, because your body has to cut its natural cycle even further.
Studies suggest that you can push your body clock back about two hours per day, meaning that you can adjust from Washington time to Colorado time in a single day, but you can move your body clock forward (as when you travel from California to Washington) only by about an hour to an hour and a half per day, Jain says.
So for Washingtonians flying to see friends or family in California, where it’s three hours earlier, your body clock should be able to adjust in less than two days. But if you’ve got a vacation planned in Paris, where it’s six hours later than here, you’ll likely need three to five days to get in sync.
You can’t entirely prevent jet lag, but you can tame it, experts say. First, time your travel well. Rest up the night before you go, and book a daytime flight if you can. Red-eye flights compound jet lag by heaping sleep deprivation on top of your body clock problems. If you absolutely must take a late-night flight, do what you can to sleep. “Don’t get sucked into watching the movie,” Jain says.
Drink, but not alcohol
Keep hydrated to avoid headaches and lightheadedness, and stay away from alcohol on the plane. Alcohol interferes with sleep, Jain says. Plus, you might end up with a hangover.
If you’re heading east, aim for an evening arrival. “You can do some work on the plane; then when you arrive, you’re tired from the travel and you can have a quick dinner [at the new dinnertime] and be ready to sleep,” Jain says. All of that helps you align with the new time schedule.