Do you ever feel sick, confused, or very tired after a long plane ride? If you were fly-ing east to west or west to east, the problem could have been jet lag. (45) Jet lag happens when your body's time clock becomes confused. Crossing several time zones may make you feel very tired. You may become confused because you are tired. In fact, you may become so confused that you won't be able to do your work. You might get headaches and feel that you have problems eating and sleeping. These are all symptoms of jet lag. However, if you feel tired after flying from north to south or south to north, you do not have jet lag. Maybe you feel tired from the tiredness and work of getting ready for the trip. You will feel better after you get some sleep. The symptoms that you feel during a flight, such as thirst and motion sickness, are not jet lag either. They are caused by the air pressure in the plane. When you travel north or south, you do not cross time zones. So you do not have true jet lag. What is jet lag?