Jet lag

Jet lag is a circadian rhythm sleep disorder that is also called time zone change

syndrome. It involves a mismatch in the timing of your natural tendency to be asleep

and the time when you are naturally awake. It occurs due to travel by airplane across

many time zones. The long trip quickly puts you in a place where you need to sleep

and wake at a time that is different than what your internal body clock expects.

This clock controls the “circadian rhythms” in your body. The word “circadian” means

to occur in a cycle of about 24 hours. These rhythms make you feel sleepy or alert at

regular times every day. Your internal clock tells your body when it is time to sleep at

night. It also tells your body when it is time to be awake during the day. Your body

clock does not have time to adjust right away to a new location due to the speed of the

travel. Complaints related to this include the following:

• disturbed sleep

• being less alert

• being unable to function normally during the day

• mild sickness

• stomach problems

• menstrual symptoms in females who travel often

Jet lag is a temporary condition. Signs of it appear one to two days after air travel

across at least two time zones. How severe it is and how long it lasts depends on the

number of time zones you cross. It is also related to the direction of travel. Flying east

tends to be harder to adjust to than flying west. Estimates are that it takes one day

per time zone for your body clock to adjust to the local time. Crossing more than six

time zones can require even more time for your body to adapt. Some people are able

to adjust more quickly than others to rapid shifts in time zones.

Jet lag can be made worse by the following:

• loss of sleep due to the travel

• a long time of sitting in an uncomfortable position

• air pressure and quality

• stress

• too much caffeine and alcohol use

Who gets it?

Jet lag affects males and females of all age groups. Pilots, flight attendants, and

business travelers are most likely to have it. This is because of how often they fly. The

elderly are likely to have a more severe problem with it. They may need much more

time to recover than younger adults.

How do I know if I have it?

1. Do you have trouble sleeping or are you very sleepy during the day?

2. Is this problem due to jet travel across at least two time zones?

3. Do you have at least one of the following problems within one to two days after

travel? These problems include:

• You are unable to function normally during the day.

• You have a general feeling of mild sickness.

• You are having stomach problems.

If your answer to each of these questions is yes, then you might have jet lag.

It is also important to know if there is something else that is causing your sleep

problems. They may be a result of one of the following:

• another sleep disorder

• a medical condition

• medication use

• a mental health disorder

• substance abuse