The blog of Crew Inc. has an analysis of what jet lag is and how to fight it.  The writer asks the question:
“Is it really such a bad thing to deal with jet lag as we slowly adjust to a new time zone?”
The answer? “Well, if you’re asking that question, you’ve never felt serious jet lag. Common symptoms involve fatigue, confusion and lack of awareness. Imagine those symptoms lasting for days as you grapple with the mental and emotional adjustment to your new surroundings.
The blog adds that studies have found that jet lag induces stress, reduces memory capacity and learning ability, throws off the normal rhythm of genes and reduces the growth of neurons in the brain.
The Crew blog and many other articles on the Web recommend adjusting your sleeping-waking schedule gradually before you depart on your trip.
But before we get into tips on how to prevent or reduce jet lag, what exactly is it?
It’s a sleep disorder. WebMD says jet lag happens to people who fly across two or more time zones. Obviously, the farther you fly, the more you’ll be affected. Also, going from west to east causes worse jet lag than flying from east to west.
According to WebMD: 
Jet lag is a temporary sleep disorder, but not temporary enough for many travelers. If you’re flying from San Francisco to Rome for a 10-day trip, for example, it may take six to nine days to fully recover. That’s because it can take up to a day for each time zone crossed for your body to adjust to the local time. If you’re traveling east to west, from Rome to San Francisco, jet lag could last four to five days — about half the number of time zones crossed. Jet lag is generally worse when you “lose time” traveling west to east.
Older people may be more deeply affected by jet lag, the article states.
People get jet lag because their biological clock or circadian rhythms get thrown off. Circadian rhythms help control when people fall asleep and wake up. The body takes cues for when to sleep from light and customary things like meals and social activities. Those cues become disrupted when you cross time zones. The body’s internal clock becomes desynchronized with the external time. It takes a while for the body to get into the rhythm of new time zones it enters.
Sleep expert Allison T. Siebern, PhD, told WebMD that other things are at work in jet lag that conspire to rob the body of its normal sleep patterns. People can become dehydrated and have the oxygen in their blood lowered by cabin pressurization. Also, people tend to sit without moving around for long periods when on airplanes.
“These can increase symptoms of jet lag and further disrupt your circadian rhythm from re-synchronizing,” Siebern told WebMD.
If the problem is very bad, WebMD even advises seeking the advice of a sleep therapist. They have ways to help the body adjust, including light therapy, medications and prescribing melatonin—a chemical produced in the body that aids in falling asleep.
It’s just about unanimous in articles on reducing jet lag that people adjust their sleep schedules before leaving. When going east, go to bed a half hour earlier every day for several night before departing, says WebMD. When going westward, go to bed a half hour later.
A psychological tip that Siebern recommends is to also adjust to the new schedule on the flight. Adjust your watch to the new time zone before you arrive. Try to sleep if it’s a night flight, but don’t force the issue. She says you can become frustrated, which interferes with sleep. If you can’t sleep, rest as much as you can, she advises.
Crew has some sage advice for people who won’t be gone long:
If your trip is short and you’re not traveling over more than three time zones, you could be better off not adjusting at all. Jim Waterhouse, a professor of biological rhythms at Liverpool John Moores University often recommends staying on the same schedule you had at home rather than trying to adjust to local time if you’re not there for long. Three days or less, for instance, is barely enough time to adjust, so it may not be worth the effort. Waterhouse suggests keeping your watch set to the time at home and acting accordingly during your trip.
If you want to know more about jetlag, check out this article: 3 key things that could solve your jetlag.
As we said in this Viter Energy blog  about the work-life balance, it's a good idea to simulate your commute to work. You don't have to drive in to work, so instead take a walk around the block just before your workday starts and just after it ends. Send yourself a psychological signal.
And if you can avoid it, do not work after your walk around the block. Don't check work email. Don't answer calls from co-workers unless you really need to talk to them (or they are friends you socialize with).
Clinical psychologist Kelcey Stratton of Michigan Health Blog  has some sound advice on finding the right time to work:
If you’re a morning person, try to schedule important work and meetings during the first half of the day. Others may peak with energy in the afternoon. Depending on the type of job you have, try to maximize on these levels as you can.
The first bit of advice is to get up from the computer, turn off your phone, and go get some exercise, do something recreational, prepare a meal, or something other than work, on the same schedule as you did when you worked at the brick-and-mortar office.
If you used to get off at 5 p.m., quit working at home at 5. You might need to check email or prepare a report later that night, but be sure to get away from all electronic communications and computing devices for a while.
Another big tip is to take your coffee breaks and lunch breaks on the same schedule, or at least be sure to take them at some point. Do not skip your favorite part of the day!