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
- 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?
- Do you have trouble sleeping or are you very sleepy during the day?
- Is this problem due to jet travel across at least two time zones?
- 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
Do I need to see a sleep specialist?
You may be able to make changes to your sleep schedule on your own. If you travel very often and continue to struggle, then you may want to visit a sleep specialist.
What will the doctor need to know?
Your doctor may want you to complete a sleep diary for several weeks. This diary should cover a period of time that includes a long trip by plane. This will give your doctor clues as to what might be causing your problems. You can also rate your sleep with the Epworth Sleepiness Scale. This will help show how your sleep is affecting your daily life. The doctor will need to know your complete medical history. Be sure to inform him or her of any past or present drug and medication use.
Will I need to take any tests?
Tests are not normally needed to see if you have jet lag. An overnight sleep study might be used to determine if there are other sleep problems. This study is called a polysomnogram. The polysomnogram charts your brain waves, heart beat, and breathing as you sleep. It also records how your arms and legs move.
How is it treated?
Travelers who are trying to avoid jet lag should plan ahead. They can slowly adjust the times that they go to sleep and wake up before they go on the trip. When the time for their trip comes, their schedule of sleeping and waking should be close to what it will be in their new location. Rest periods, exercise, and the use of light therapy can also help you overcome the effects of jet lag.
SOURCE: American Academy of Sleep Medicine; Reviewed by David A. Kristo, MD