Perhaps jet lag is the culprit. Crossing time zones while you travel is just one of the causes. Some advance knowledge and preparation can result in a more enjoyable trip.
PRIMARY CAUSES OF JET LAG
* Crossing two or more time zones: This is worse on eastbound flights because you have to adjust to an earlier schedule.
* Lack of sleep before you travel.
* Physical exhaustion from doing too much too quickly just before you leave.
* Dehydration: Aircraft air is very dry. Drink plenty of water (not soda, coffee or tea). Some people take their own bottled water with them.
* Disruption of the body’s normal wake/sleep schedule (circadian rhythm).
* Alcohol consumption: Alcohol contributes to dehydration. At altitude, affects of alcohol are magnified several times.
* Stale air: Aircraft air is not as oxygenated as outside air. It also contains odors and minute particles emanating from passengers, crew, luggage and the aircraft.
* Inactivity and lack of exercise.
* Climate change.
POSSIBLE SYMPTOMS OF JET LAG
* Slow reflexes – especially dangerous while driving
* Sluggish thought...