What Is Jet Lag?

Jet lag is a common phenomenon that affects travellers when they navigate multiple time zones. It can interrupt sleep patterns, lead to fatigue, and cause many symptoms that make adjusting to a new time zone challenging. Here are some knowledge and tips to help you understand and minimize the effects of jet lag.

Jet lag occurs when rapid travel across time zones disturbs your body's internal clock, known as the circadian rhythm. Symptoms of jet lag include fatigue, insomnia or disturbed sleep, difficulty concentrating, irritability, digestive issues, and discomfort. 

Jet lag severity varies depending on factors such as the number of time zones crossed and individual flexibility. In the following sections, we will delve deeper into the causes of jet lag, explore the science behind circadian rhythms, and provide additional perceptions and strategies to improve jet lag symptoms effectively and adapt to new time zones.


Jet lag is a result of rapid travel, and while there isn't a perfect solution, there are some strategies that can help manage it. Planning is key, and experts suggest getting enough sleep before your trip as you'll likely experience some sleep deficit upon arrival. Adjusting your watch to the destination time when boarding the plane can serve as a reminder to adjust your sleep and meal times. During the flight, it's best to moderate your food, alcohol, and caffeine intake, as they can affect your sleep patterns. Arriving at your destination closer to bedtime can also be beneficial. When planning your activities after arrival, consider your body's internal clock and schedule important tasks when you're most alert. For short trips, it may be easier to stick to your home time zone, while for longer trips with no immediate important activities, a few days of decreased performance may be acceptable. It's important to choose interventions based on your needs and itinerary, and melatonin is recommended as a standard therapy. Adjusting sleep schedules, and using light therapy, caffeine, or short-term sleep aids are considered options with varying evidence. It's crucial to be cautious with untested interventions, especially medications, and consider their safety and potential side effects. Ultimately, it's up to each traveler to find the best approach that suits their needs. 1

Causes of jet lag

When you travel across different time zones in a short span of time, the internal clock in the body gets disturbed which is the major cause of jet lag. The internal clock is also termed as a circadian rhythm that regulates our sleep-wake cycle and some other functions of the body. When you travel to a new time zone, your body needs time to adjust to the local time, which leads to a mismatch between the internal clock and the external environment. The severity of jet lag can be influenced by the direction of travel and the number of time zones crossed. Changes in exposure to light, meal times, and daily routine body needs can also contribute to jet lag.

Signs and symptoms of jet lag

The main symptoms of jet lag are:

  • Difficulty sleeping at night time and waking up in the morning
  • Tiredness and exhaustion
  • Difficulty staying awake during the day
  • Poor sleep quality
  • Concentration and memory problems
  • Indigestion
  • Vomiting sensation (nausea)
  • Constipation
  • Changes in appetite 
  • Mild anxiety2

Management and treatment for jet lag

To mitigate jet lag, consider the following strategies:

  • Gradually adjust your sleep schedule: Begin shifting your sleep routine a few days prior to your trip to align with the destination time zone
  • Stay hydrated: Drink plenty of water before, during, and after your flight to counteract the dehydrating effects of air travel
  • Avoid alcohol and caffeine: These substances can disrupt sleep patterns and worsen jet lag symptoms
  • Seek natural light exposure: Spend time outdoors in natural light to help reset your circadian rhythm.
  • Take short naps: If you feel tired during the day, opt for brief power naps that won't interfere with your regular sleep schedule
  • Consider melatonin: Taking melatonin, a hormone that regulates sleep, at the appropriate time can aid in resetting your internal clock


Jet lag is a condition that affects people when they travel across multiple time zones. It is diagnosed based on specific criteria, including experiencing excessive daytime sleepiness or disruptions in the sleep cycle, along with decreased total sleep time after traveling across at least two time zones. Symptoms such as fatigue and physical discomfort typically appear within two days of travel, and there should be no other underlying sleep disorder causing the disturbance.

Sometimes, people confuse jet lag with travel fatigue. Travel fatigue is a syndrome characterized by generalized fatigue, occasional headaches, and mental weariness caused by disruptions in sleep routines during travel. Unlike jet lag, travel fatigue is not dependent on the number of time zones crossed and can occur after traveling northbound or southbound. Restful sleep often helps alleviate the symptoms of travel fatigue.

In the absence of specific treatments, our body's natural circadian rhythm gradually adjusts to the local time of the destination. On average, this adjustment occurs at a rate of approximately one time zone per day for eastbound travel and 1.5 time zones per day for westbound travel.

It's important to note that jet lag can vary in severity from person to person and may affect individuals differently. While there is no specific cure for jet lag, there are management strategies and lifestyle adjustments that can help alleviate its symptoms and aid in the adjustment process.

Risk factors

The major risk factors that enhance the jet lag symptoms are sleep deprivation, Extended periods of sitting in positions that cause discomfort or unease, quality of air and pressure, increased intake of caffeine and alcoholic intake.3


Jet lag can cause various complications involving physical and mental dysfunctions. Fatigue and disordered sleeping patterns can result in decreased alertness, disrupted cognitive function, and difficulty in concentrating. This can inhibit productivity, performance, and overall wellbeing. Disturbances in appetite disturbances, indigestion and bowel irregularities may also occur. Mood changes, irritability and feelings of disorientation are common. Jet lag also weakens the immune system, making the travels more subjective to illnesses. In some cases, severe jetlag results circadian rhythm sleep disorder that requires medical intervention. Proper management and good adaption strategies are very important to minimize the complications associated with jet lag.  


How can I prevent jet lag

To prevent jet lag, gradually adjust your sleep schedule to match the destination time zone a few days before your trip and stay hydrated by drinking plenty of water before, during, and after your flight.

How common is jet lag

Jet lag is a common occurrence, especially among individuals who frequently travel across multiple time zones. It is estimated that the majority of long-distance travelers experience some degree of jet lag symptoms.

What can I expect if I have jet lag

The symptoms that are experienced for jet lag such as fatigue, disorders in sleep patterns, difficulty in concentrating, irritability, digestive problems and discomfort. These symptoms may differ by time zones that you are travelling and exposure to sunlight. 

When should I see a doctor

For jet lag, it is not necessary to visit a doctor as it is a temporary condition that resolves on our own. However, if you are experiencing symptoms that are severe and persistent, or if jet lag significantly impacts your health, it may be advisable to consult a healthcare professional for further evaluation and guidance. 


Jet lag is a common condition experienced by travelers crossing multiple time zones.It is caused by a disruption of the body's internal clock, known as the circadian rhythm, due to rapid travel. Symptoms include fatigue, disrupted sleep patterns, difficulty concentrating, irritability, digestive issues, and a general sense of discomfort.

The severity of jet lag can vary depending on the number of time zones crossed and individual factors.Strategies to prevent or minimize jet lag include gradually adjusting sleep schedules before the trip, staying hydrated, avoiding alcohol and caffeine, seeking natural bright light exposure, taking short naps, and considering melatonin supplementation.

Jet lag is diagnosed based on specific criteria, and it is different from travel fatigue, which is not dependent on the number of time zones crossed.

Complications of jet lag can include decreased alertness, impaired cognitive function, digestive problems, mood changes, weakened immune system, and the possibility of developing a circadian rhythm sleep disorder.

Most cases of jet lag do not require medical intervention and can be managed with lifestyle adjustments.It is advisable to consult a doctor if the symptoms are severe, persistent, or significantly impact daily functioning and well-being.

Jet lag is a temporary condition that typically resolves on its own as the body adjusts to the new time zone.


  1. Jet lag - an overview | sciencedirect topics [Internet]. [cited 2023 Jul 4]. Available from: https://www.sciencedirect.com/topics/neuroscience/jet-lag 
  2. nhs.uk [Internet]. 2017 [cited 2023 Jul 4]. Jet lag. Available from: https://www.nhs.uk/conditions/jet-lag/ 
  3. Choy M, Salbu RL. Jet lag. P T [Internet]. 2011 Apr [cited 2023 Jul 5];36(4):221–31. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3086113/ 
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Lekha Lachubuktha

Masters in Neuropharmacology, Nottingham Trent University

Lekha is an enthusiastic and talented medical writer with a deep passion for effective science communication. With a background in Neuropharmacology and Pharmacy, she brings fresh insights and a thirst for learning to her writing, contributing to advancing health awareness and knowledge. As a new starter, Lekha is excited to embark on this journey, utilizing her extensive knowledge and hands-on experience to make a meaningful difference in medical writing.

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