What Is Jet Lag?

Jet lag is a sleep disorder caused by rapid travel across time zones (jet, or airplane, rather than car or train travel). The medical terms for jet lag are desynchronosis or circadian dysrhythmia. Humans have an internal clock, or circadian rhythm, that has evolved in response to living on a planet with a 24-hour day. This internal clock serves to regulate many of the body’s biological functions, including the sleep-wake cycle. This natural synchronization between body and day is thrown off by fast travel over great distances to the east or west (not north or south in the same time zone).  

Jet lag is temporary but can be a source of serious discomfort while it lasts. It is also quite common, potentially affecting anyone who flies across time zones for work, school, vacation, or any other reason. If you travel regularly and are troubled by jet lag, contact a primary care physician or sleep specialist at Baptist Health.

What Are the Symptoms of Jet Lag?

A number of symptoms are common to jet lag:

• Fatigue
• Difficulty sleeping or problems falling asleep at the wrong times
• Reduced concentration
• Gastrointestinal upset, including nausea, constipation, and diarrhea
• Irritability and mood swings
• Grogginess or a sense of feeling “off”

Though symptoms vary by individual, the greater the distance traveled, the more likely they are to be severe.

What Causes Jet Lag?

There are several ways in which travel can disrupt the body’s circadian rhythm:

• Clock disparities: The basis for jet lag is that your body’s internal clock doesn’t agree with the clock at your destination. If you fly to Hawaii from the Eastern Time Zone, you might arrive at 7:00am with your body telling you that it is 1:00pm.
• Sleep disparities: Travel can interrupt normal sleep patterns. People on jets tend to sleep too much or at the wrong times, due to the lower oxygen levels of high altitudes or out of boredom and lack of physical activity. You may be sleepy when you arrive where you’re going but you won’t be able to rest properly in the middle of the day.
• Sunlight disparities: Excessive light, either from overhead lights, computer screens, or flying above the clouds, can also play a role in jet lag. The body produces melatonin, a hormone, in response to dimming light, as a means of preparing for sleep. The continual presence of light interferes with melatonin production.
• Travel fatigue: Travel can be tiring, even without the risk of jet lag. Symptoms, such as headaches and nausea, amplify the effects of long-distance flying.
• Dehydration: There is evidence that dehydration worsens jet lag. Cabin air tends to be dry, which accelerates water loss.
• Caffeine and alcohol: Neither drinking coffee (to stay awake) nor alcohol (to calm anxiety and bring on sleep) are effective ways of dealing with jet lag. In fact, they tend to exacerbate symptoms by altering sleep patterns and increasing dehydration.

Jet lag discriminates by age: older persons tend to feel symptoms more acutely than the young. Also, traveling east magnifies the impact of jet lag more than traveling west.

How Is Jet Lag Treated?

Because jet lag is temporary – your body will usually adjust to new circumstances in a few days – it rarely requires a medical response. However, physicians will sometimes prescribe treatment for persons who travel frequently and regularly experience jet lag:

• Medications: The most common prescription medication for jet lag is soporifics or sleeping pills. These include benzodiazepines. These can be taken with the goal of supporting regular sleep, but are potentially addictive and also have undesirable side effects.
• Light therapy: Light therapy is a second method for supporting a normal pattern of sleep. Exposure to light during daylight hours – either natural outdoor light or lamps when working inside – restricts the production of melatonin to those time periods when sleep is appropriate.

Though jet lag is classified as a type of sleep disorder, it isn’t particularly harmful. Keep in mind that it will go away on its own, as your body adjusts to new circumstances.

How Do I Prevent Jet Lag?

There are several steps you can take to prevent or diminish the effects of jet lag:

• Be smart about flight selection: Pick your flights carefully. If you arrive at your destination in the evening, you’re more likely to sleep when the clock indicates bedtime.
• Be prepared to sleep en route: If you’re flying at night and have trouble sleeping on a plane, bring an eye mask and earplugs.
• Cat naps aren’t just for cats: If you arrive sleepy during the middle of the day, check into your hotel and take a quick cat nap. A brief sleep can be surprisingly effective at keeping you up until nighttime.
• Eat healthy: Fresh fruits and vegetables can help you stay hydrated. Snack foods, on the other hand, offer a quick energy boost but can leave you feeling depleted later on.
• Limit alcohol and caffeine: Better to maintain your normal sleep habits than adjust them artificially with beer, wine, cocktails, or coffee. If you do need to sleep, a healthy alternative to alcohol is a non-caffeinated herbal tea.
• Exercise: Granted, not easy to do on a plane, but at least stretch your legs or move up and down the aisle when the seatbelt signs are off. If changing flights, airports are great places for walking.
• Adjust before you go: You might try adopting your destination time—a few days before you leave, schedule getting up and going to bed earlier or later, depending on where you’re headed.

Learn More About Jet Lag from Baptist Health

Don’t be grounded by jet lag. If it becomes an issue in your life, see your Baptist Health primary care physician or sleep specialist.