Understanding Jet Lag: Research Insights and Effective Strategies for Relief and Adjustment

Jet lag affects millions of travelers every year, disrupting sleep, mood, and overall well-being. Crossing multiple time zones quickly throws off the body’s internal clock, leading to fatigue, difficulty concentrating, and digestive issues. Understanding what jet lag is, what research reveals about its causes, and how to manage it can help travelers minimize its impact and adjust more smoothly to new time zones.

Traveler observing sunrise from airplane window, symbolizing transition between time zones

What Is Jet Lag?

Jet lag, also called desynchronosis, occurs when the body’s internal clock, or circadian rhythm, is out of sync with the local time at the destination. The circadian rhythm regulates sleep-wake cycles, hormone release, body temperature, and other physiological processes on roughly a 24-hour schedule. Rapid travel across time zones disrupts this rhythm because the body’s clock remains aligned with the original time zone.

Symptoms of jet lag include:

• Difficulty falling asleep or staying asleep at night

• Excessive daytime sleepiness

• Fatigue and reduced energy

• Difficulty concentrating or impaired cognitive function

• Digestive problems such as indigestion or loss of appetite

• Mood changes like irritability or mild depression

  
  

The severity of jet lag depends on the number of time zones crossed, direction of travel, individual differences, and the timing of exposure to light and activity.

What Research Says About Jet Lag

Scientific studies have deepened our understanding of how jet lag works and how to reduce its effects. Key insights include:

• Circadian rhythm adjustment takes time: The body typically adjusts its internal clock by about one hour per day after crossing time zones. This means a 6-hour time difference may require nearly a week for full adjustment.

• Travel direction matters: Traveling east tends to cause worse jet lag than traveling west. This is because it is easier for the body to lengthen its day (westward travel) than to shorten it (eastward travel).

• Light exposure is critical: Light is the strongest cue for resetting the circadian rhythm. Exposure to natural light at the right times helps shift the internal clock faster.

• Melatonin plays a role: Melatonin is a hormone that signals the body to prepare for sleep. Supplementing melatonin at the right time can help realign the sleep-wake cycle.

• Individual differences affect symptoms: Age, chronotype (morning or evening preference), and overall health influence how severely someone experiences jet lag.

  
  

A 2019 review in the Journal of Travel Medicine highlights that combining behavioral strategies with timed light exposure and melatonin supplementation offers the best results for managing jet lag.

Strategies to Avoid or Minimize Jet Lag

While it is impossible to completely avoid jet lag when crossing multiple time zones, travelers can reduce its impact by preparing before and during travel.

Before Travel

• Gradually shift your schedule: Adjust your sleep and meal times closer to the destination time zone a few days before departure. For eastward travel, go to bed and wake up earlier; for westward travel, do the opposite.

• Get plenty of rest: Start your trip well-rested to reduce fatigue.

• Stay hydrated: Dehydration worsens jet lag symptoms, so drink plenty of water before and during the flight.

• Avoid alcohol and caffeine: These can disrupt sleep and dehydrate you.

  
  

During Travel

• Set your watch to the destination time: Mentally align yourself with the new time zone.

• Sleep on the plane according to destination night: Try to sleep if it’s nighttime at your destination, or stay awake if it’s daytime.

• Move around regularly: Walk and stretch to improve circulation and reduce stiffness.

  
  

After Arrival

• Seek natural light exposure: Spend time outdoors during daylight hours to help reset your internal clock.

• Follow local meal and sleep schedules: Eat and sleep according to the new time zone, even if you don’t feel hungry or tired.

• Avoid naps longer than 20 minutes: Short naps can help, but long naps may delay adjustment.

• Use caffeine strategically: A moderate amount in the morning can boost alertness but avoid it late in the day.

  
  

How to Adjust to Jet Lag Faster

Adjusting quickly requires actively resetting your circadian rhythm. Here are some evidence-based tips:

• Use light therapy: Bright light boxes or timed exposure to sunlight can shift your internal clock. For eastward travel, morning light helps advance the clock; for westward travel, evening light delays it.

• Take melatonin supplements: Low doses (0.5 to 3 mg) taken 30 to 60 minutes before desired bedtime at the destination can improve sleep onset and quality. Timing is crucial—taking melatonin at the wrong time can worsen jet lag.

• Maintain consistent sleep routines: Go to bed and wake up at the same time daily to stabilize your rhythm.

• Consider short-term use of sleep aids: Under medical advice, short-term use of medications like zolpidem may help with sleep, but they do not address circadian misalignment.

  
  

Supplement Considerations for Jet Lag

Melatonin is the most studied supplement for jet lag. Research shows it can reduce the time it takes to fall asleep and improve sleep quality when taken appropriately. However, it is not regulated as strictly as medications, so quality varies between brands.

Other supplements sometimes used include:

• Magnesium: May promote relaxation and improve sleep quality.

• Valerian root: Traditionally used for sleep, but evidence is mixed.

• B vitamins: Some suggest they support energy metabolism, but no strong evidence for jet lag relief.

  
  

Always consult a healthcare provider before starting supplements, especially if you take other medications or have health conditions.

Practical Example: Managing Jet Lag on a 10-Hour Eastward Flight

Imagine traveling from New York to Paris, crossing 6 time zones eastward. To reduce jet lag:

• Start shifting bedtime 1 hour earlier each night 3 days before departure.

• Stay hydrated and avoid caffeine on the flight.

• Try to sleep during the flight when it is nighttime in Paris.

• Upon arrival, spend time outdoors in the morning sunlight.

• Take 1 mg of melatonin 30 minutes before bedtime Paris time for the first 3 nights.

• Avoid long naps and maintain a consistent sleep schedule.

  
  

This approach can help reduce jet lag symptoms and speed adjustment.

Jet lag results from a mismatch between the body’s internal clock and the new time zone. Research shows that light exposure, melatonin, and behavioral changes can help realign the circadian rhythm. Travelers who prepare ahead, manage their exposure to light, and use supplements wisely can reduce symptoms and adjust faster. Next time you plan a trip across time zones, use these strategies to arrive feeling more refreshed and ready to enjoy your destination.

Real progress starts with the right plan—and the right support.

With Punzy Fitness, you’ll get weekly coaching, personalized movement assessments, and clear next steps tailored to your goals.

👉 Apply for online coaching and start moving better, feeling stronger, and living healthier.

Disclaimer:

The information shared in this article is for educational purposes only and is not a substitute for professional medical advice. Always consult with your healthcare team before beginning a new exercise program, using supplements, or making dietary changes, especially if you have existing health conditions.