Here’s a serious look at jet lag by Jane Brody of the IHT:
“The biological disruptions of jet lag are made worse by the fatigue induced by a long flight - the many hours spent in a cramped, dehydrating environment where the air is bone-dry and low on oxygen, the food can be worse than dreadful, and the opportunity for on-board exercise is ever more restricted, in part by security concerns.”
Read the entire article which examines several coping strategies here.