The head-spinning, mouth-drying, bone-crushing fatigue of jet lag is enough to make anyone think twice about changing time zones. But sometimes, traveling is worth the suffering — or, it’s just unavoidable. So we quizzed Stanford sleep expert Jamie Zeitzer about how to minimize the misery of jet lag.

The body operates on a biological schedule known as the circadian clock. Seeing daylight at specific times of day helps set this clock — but it’s slow to adjust when we rapidly jet across time zones. That lag accounts for some of the nighttime sleeplessness and daytime sluggishness we experience while traveling, Zeitzer says. Packing into an airplane and eating unusual food at unusual times probably doesn’t help much, either. “There are so many things that are going wrong at once,” he says.

Some people withstand jet lag better than others — possibly because they may be more sensitive to light, they’re simply better at falling asleep, or they’re just more tolerant of discomfort. It’s also somewhat less painful adjusting to time zone shifts when traveling from east to west, than from west to east. That’s because the body’s drive to stay awake is strongest in the hours before you typically go to sleep. So trying to fall asleep at 11PM in New York when your body is telling you that it’s 8PM in California is much harder than staying up later on trips in the opposite direction.

So, what does that mean for your next trip? Here’s what we learned:

The following interview has been edited and condensed.

What are the steps people should take when they are returning from vacation, or leaving for vacation, to adjust more rapidly — and not feel like garbage?

So, light is really the key. It’s not only the amount of light, it's also the timing of the light. So, if you are going east-to-west you’ll want to get evening exposure to light. And if you’re going west to east, you’ll want to get morning exposure to light. That’s the general rule of thumb. And of course, this is all more easily said than done. But that would make you resynchronize the most rapidly. It’s basically adjusting to your new schedule as rapidly as possible, and getting the light.

There are more advanced ways to do it as well. That gets into the jet lag apps. The best one is a colleague of mine's, Danny Forger, who's at the University of Michigan, called Entrain. It's a free app that basically provides different kinds of alternative schedules to help more rapidly synchronize you to your new time zone.

Like, ahead of time?

This is during the travel. This is basically all based on mathematical modeling — and now he's collecting data to see what happens in the real world.

What else can people do?

There’s a lot of other stuff people put out there — diets and stuff like that. But I haven’t been too enthused about any of the various kinds of dietary programs that people put out there.

And some people also like using melatonin, which has two effects. One is that it can change the timing of the circadian clock — but it’s just not that effective at doing it. And the second is that it acts as a mild hypnotic, so it's a mild sleeping drug that is mainly effective during the daytime. The melatonin at night really has very little effect when you take extra.

Because it’s found in many different organisms, including in bananas and rice in nanogram quantities, the FDA calls it a nutraceutical — which makes it the only hormone that is not actually regulated by the FDA. So, basically, when you go and buy it in the store, there's no regulation on potency and purity. You don't know if it's melatonin, or if it’s all filler, or what's in there because there's absolutely no regulation. So if people use it, I always suggest that they look for one that, if you check out the website, tells you how they manufacture it and whether or not they use good manufacturing procedures. But it’s still kind of a risk to take it.

Should a person with jet lag avoid naps?

There are people who use prophylactic napping, and that's usually good. So if you’re traveling east to west, you’re going to stay up later than you normally would. If you take a nap earlier in the day, it's easier to stay up later.

It’s trickier going the other way, when you're traveling west to east. Because then you’re trying to sleep when your body is telling you to stay awake. It's actually one of the more difficult parts, because in the hours before your habitual bedtime, the circadian system is most strongly signaling for you to stay awake.

There’s a lot of talk about how blue light on screens keeps you awake. Let's say I travel to Australia and I need to stay up longer than I would normally, should I stare at my computer screen as hard as I can?

The thing is that photon for photon, it is a stronger stimulation than other wavelengths of light — this is a true fact. But the amount of light emitted from your e-reader, notebook, computer, iPhone, computer, isn’t a heck of a lot. If you have normal light exposure during the daytime, it has very little effect.

So reading on my iPad won't make my jet lag worse, in the other direction?

It won't make it worse — and, you asked, will it help keep you up? If doing something actively engaging keeps you up, then it's a useful thing to keep you awake. Alternatively, it could bore you to tears and make you fall asleep. Some people like reading a book in order to feel tired and fall asleep. And so they shouldn’t be fearful that using a backlit reader is going to cause them to stay awake more than a book would cause them to fall asleep.

What do you do?

Suffer. I hate flying. So when, I fly I try not to be awake any of the flight.

Does that mess you up when you land?

Oh yeah. It takes me like a day to adapt.