Jet Lag - Symptoms and Causes

Overview

Jet lag disorder happens when people travel quickly across multiple time zones. This sleep problem occurs because our bodies have internal clocks, called circadian rhythms, that tell us when to be awake and when to sleep.

These rhythms stay synchronized to our original time zone even after traveling. The severity of jet lag often depends on how many time zones you cross. More zones typically mean more noticeable symptoms.

Common effects include:

Feeling tired during the day
General discomfort
Difficulty concentrating
Digestive problems

While these symptoms don’t last forever, they can make your vacation or business trip less enjoyable.

Fortunately, there are strategies to reduce jet lag’s impact on your travel experience.

The body’s natural adjustment process takes time, but with proper planning, travelers can minimize disruption to their sleep patterns and enjoy their destinations more fully.

Signs of Jet Lag

The signs of jet lag typically appear within one to two days after crossing at least two time zones. The longer your journey, the more severe your symptoms might be.

Flying eastward often causes worse jet lag than traveling west. Recovery usually takes about one day for each time zone you cross.

When Medical Help Is Needed

Though jet lag doesn’t last forever, frequent travelers who often struggle with it might benefit from talking to a sleep expert. If jet lag regularly disrupts your life, professional advice could help.

Jet lag can cause several problems, including:

Sleep issues – trouble falling asleep or waking up too early
Feeling tired during the day
Mental fog – difficulty concentrating or performing normal tasks
Digestive problems like constipation or diarrhea
General discomfort or feeling unwell
Changes in mood

These symptoms vary from person to person. You might experience just one or several of these issues when traveling across time zones.

Why Jet Lag Happens

When Your Body Clock Gets Confused

Jet lag happens when you fly across at least two time zones. This travel disrupts your body’s internal clock, which controls when you feel sleepy or awake.

Your body runs on a 24-hour cycle that helps regulate sleep, hunger, and other functions.

For instance, if you leave New York at 4 p.m. and arrive in Paris at 7 a.m., your body still thinks it’s 1 a.m. While Parisians are starting their day, your body is telling you it’s time to sleep.

Your body needs time to adjust to the new schedule, which is why jet lag symptoms can last for several days.

How Light Affects Your Body

Sunlight plays a crucial role in regulating your body clock. Light affects how your body produces melatonin, an important hormone that helps coordinate many bodily functions.

When your eyes detect light, they send signals to a brain region called the hypothalamus. This process works like this:

During daylight: Your brain limits melatonin production, helping you stay alert.
At night (darkness): Your brain signals the pineal gland to release melatonin, making you sleepy.

This is why exposure to daylight in your new location can help reset your body clock. However, timing this exposure correctly is important for it to be effective.

Airplane Conditions and Your Body

The airplane environment itself might contribute to jet lag symptoms, even if you don’t cross time zones. Research shows that:

Cabin pressure changes can affect how you feel.
High-altitude flying may cause physical discomfort.
Low humidity in airplanes can lead to mild dehydration.

The dry air in airplanes means you need to drink more water than usual. If you don’t stay properly hydrated during your flight, you might experience worse jet lag symptoms when you arrive at your destination.

Risk Factors

Several factors can make jet lag more likely or more severe:

Time Zone Changes: The more time zones you cross during travel, the worse your jet lag may be.
Direction of Travel: Flying eastward often causes worse jet lag than flying westward because you lose hours in your day.
Frequent Flying: People who fly often, such as airline crew members and business travelers, face a higher risk of regular jet lag.
Age: Older travelers typically need more time to recover from jet lag symptoms than younger people do.

Complications

Drowsy driving raises the risk of car accidents, especially for people who are jet-lagged. When your body’s internal clock is disrupted from travel across time zones, your alertness and reaction time can suffer significantly. This makes driving particularly dangerous.

Jet lag affects:

Concentration
Decision-making ability
Response time

Warning signs of drowsy driving:

Frequent yawning
Difficulty keeping eyes open
Drifting between lanes
Missing exits or turns

People traveling for business or vacation should be extra careful when driving in new time zones and consider alternative transportation if feeling sleepy.

Prevention

Preventing jet lag or reducing its effects requires planning and strategy. Here are several effective approaches to minimize the impact of time zone changes on your body:

Arrive with Time To Spare

If you have important commitments at your destination, plan to arrive a few days ahead of time. This gives your body time to adjust to the new time zone before you need to perform at your best.

Get Adequate Sleep Before Traveling

Begin your journey well-rested. Starting a trip already sleep-deprived can make jet lag symptoms more severe and recovery more difficult.

Adjust Your Schedule Gradually

Before your departure, slowly shift your sleep and eating patterns. For eastward travel, go to bed 1 hour earlier each night for several days.

For westward travel, go to bed 1 hour later each night for several days. Also, adjust meal times to match your destination schedule when possible.

Use Light Exposure Strategically

Light strongly influences your body’s internal clock. After flying west, seek evening light to help adjust to a later time zone. After flying east, get morning light to adapt to an earlier time zone.

For travel across more than 8 time zones, you should:

Wear sunglasses in the morning and seek afternoon sunlight for eastward travel
Avoid bright light before sunset during your first few days for westward travel

Commit To the New Schedule Immediately

Set your watch to the destination time before takeoff. Once you arrive, try to follow local time patterns. Stay awake until local bedtime, eat meals at local mealtimes, and avoid napping during the day.

Stay Well-Hydrated

Drink plenty of water before, during, and after your flight. The dry air in airplane cabins can cause dehydration, which worsens jet lag symptoms. Limit alcohol and caffeine as they can dehydrate you and disrupt sleep patterns.

Sleep Strategically During Travel

If it will be nighttime when you arrive, try to sleep on the plane using earplugs, headphones, and eye masks.

If it will be daytime at your destination, stay awake during the flight to help adjust to local time more quickly.