The difference in time that occurs when we cross TIME ZONE.
We have internal clock that determines when we should sleep, wake up, eat, or perform other functions during a 24-hour period. So most travelers are not able to adjust to the shorter or longer day.
How can deal with JET LAG?
To minimize the effects of JET LAG a scheduling arrangement should be considered for an early evening arrival.
That would force travelers just go to bed in short time after they get in their hotel rooms. But there is also some evidence that light plays a role in accommodating a new sleep cycle. In addition, it seems that a FULL STOMACH increases the symptoms of restless and fatigue. In fact, eating a small meal on the plane should help as long as travelers don't find the nearest restaurant when they land.
Finally, ALCOHOL tends to dehydrate the body, which appears to make JET LAG worse. So that's why it's better to drink lots of water and avoid drinking alcohol on the plane.
Researchers tell us how long it takes to adjust to a new TIME ZONE
Some studies show that we (Pilots, Flight Attendants and Travalers) require half a day for each TIME ZONE crossed. So if you can't include a stopover on a long flight, it is better not to schedule an important meeting for the day after your arrival.
For Brazilian crew only
(Law 7183, April 5, 1984)
Chapter II - Workload Rules
Section V - Flight and Landing Limits
Article 28 - "Flight-hour" is a period of time between the initial plane taxi to takeoff and the engines shutdown time after landing.
Article 29 - "Flight-hours" and Landing time limits for single or minimum crew as stated on aircraft certifications should be:
a) 09:30 hours and 5 Landings
Section VI - Job Rest Period
Article 34 - Thes rest is a period of time without interruption in which any crewmember has no duty to perfom after a flight journey.
a) The Job rest will last at least 12 hours after 12-hours-flight journey.
Article 35 - 2(two) hours will be add to rest time per each TIME ZONE crossed and the rest will be accomplished after crewmembers have endend their flight jouney and they have come back to their home bases.