How To Reduce Jet Lag – Methods To Adjusting Your Internal Clock In Different Time Zones

Whether you are an individual who occasionally travels on a plane for a vacation or a business man/woman who frequently travels on a plane to conduct business in international countries.

You most likely have experienced jet lag at some point or another. You probably asked these questions before:

How to reduce jet lag?

Why does it take me a few days to adjust to a new time zone after every flight on a plane?

Why do I wake up very early or have a difficult time going to sleep even though it still feels like afternoon?

how to reduce jet lag

If this has ever happened to you before, the good news is that there are steps that you can take to minimize the effects of jet lag and in some circumstances completely avoid it all together.

In this article, you will discover on how to reduce jet lag, steps to take before traveling to different time zones, during the flight, and methods to adjusting your internal clock once you have reached your destination.

Table of Contents

  1. Causes Of Jet Lag
  2. Symptoms Of Jet Lag
  3. How To Prevent Jet Lag By Researchers
  4. Techniques To Combating Jet Lag
  5. Jet Lag Calculator Comparisons
  6. Glasses and Lightboxes
  7. Methods To Minimize Traveling Fatigue
  8. Does Melatonin Help?

Causes of Jet Lag

Internal Clock Disruption

This sleep disorder happens when you traverse over two or more different time zones. When you travel across these time zones, the new times of day and night will not line up with your own internal clock.

This has a direct correlation to the level of alertness you feel throughout the day and your ability to go to sleep at night.

The way you sleep is very much managed by your internal clock and it follows a 24-hour period that is referred to as a circadian rhythm.

Your biology impacts your internal clock. However, outside factors such as the level of light and darkness play an important role as well.

The body’s internal clock is astonishingly firm and does not enjoy changing very much. There is research that shows that the majority of people can only shift their internal clock by 1 to 1 1/2 hours each day.

For example, a seven-hour time zone change can take 5 to 7 days before you are fully adjusted.

Alarm clock.

How Sunlight Plays Its Part

One of the most imperative external factors that influences your internal clock is the cycle of light and dark.

Controlling the amount of time that you spend outside when daylight is present can help alter the time that you wake up and go to sleep.

The internal clocks of most people are inclined to run slow. If left own its own, it would shift by a few minutes each day.

Yet, your daily routine of sleep and your exposure to light helps keep your clock in line at 24 hours.

Sunlight on cloudy day.

This natural shift explains why it is predominately quicker to move your internal clock when traveling west rather than traveling east.

A good rule of thumb is that you can anticipate to make an hour change each day after a flight that is eastbound and make an hour and a half change each day after a flight that is westbound.

Symptoms Of Jet Lag

The most prevalent symptoms of jet lag include:

  1. Indigestion.
  2. Diarrhea or constipation.
  3. Dehydration.
  4. Changes in appetite.
  5. Feeling disorientated or dizzy.
  6. Sweating.
  7. Concentration loss.
  8. Feeling irritable.
  9. Feeling lethargic.
  10. Feeling worn out during the day.
  11. Inclination to sleep throughout the day.
  12. Waking up earlier in the morning than anticipated.
  13. Having a hard time going to sleep at night in a different time zone.

It is helpful to understand the distinction between travel fatigue and jet lag, especially if the overall symptoms are similar to one another.

Travel fatigue can be controlled rather fast especially after a rest and a good night of sleep. The exhaustion that is felt from jet lag can remain with you until you be accustomed to the new time zone.

In a later part of this article, I will recommend some methods that will help you minimize travel fatigue from your voyage.

How To Prevent Jet Lag By Researchers

During 2009, there were some researchers from the Rush University Medical Center in Chicago that published a very interesting article about jet lag – How To Travel The World Without Jet Lag.

The researchers revealed that changing your internal clock with a controlled exposure to strong light is the best method to handling jet lag. The also had a recommendation that taking melatonin supplements can assist as well.

Techniques To Combating Jet Lag

According to the research that was done by Rush University, there are three different techniques to help you face the changes in time zones.

1. Do not fret about changing to a new time zone on short trips

In the case that the change in time is fewer than three hours and it is a short trip. It is for the better if you did not make an attempt to adjust to the new time zone.

Rather it is better for you to maintain your usual sleep schedule. If the time difference is greater than three hours, then you should change your sleep schedule as much as needed.

2. Change to a new time zone after you arrive

For the most part, this is most likely what the majority of people usually do. However, it can take approximately a day for each hour of time difference prior to finally relieving the feeling of jet lag.

In some cases, it can take more time to combat jet lag if you are not aware of the external factors such as sunlight which has an effect your internal clock.

3. Plan and create calculated adjustments before departing

By making the necessary changes to the amount of sunlight that you are exposed to and the time that you go to sleep. It is completely possible to alter your internal clock so that it is closer to the new time zone before you depart.

These adjustments will minimize the amount of time that you experience from jet lag before you reach your destination. However, modifying your sleep schedule in advance can be challenging due to social, personal, or work related causes.

The benefit of this approach is that it can possibly allow you to reach your destination with almost no jet lag.

This method has gained many supporters, primarily among top athletes and traveling business people. These types of people need to be in top shape when they arrive to their destination in spite of the new time zone.

Ways That Modifying Your Meal Times Can Help

During 2016, a group of researchers at Surrey University in the United Kingdom coordinated an interesting study on jet lag using a 60 long haul cabin crew.

The discovered that adhering to normal meal times based on a new time zone helped relieved their jet lag. The author of the study announced:

“We found that many crew tend to rely on sleep rather than eating strategies to alleviate symptoms of jet-lag, but this study has shown the crucial role meal times can indeed play in resetting the body block”.

An important tip to remember is to eat your meals that are based on a new time zone as soon as you can even if feels unusual in the beginning.

Jet Lag Calculator Comparisons

Jet lag calculators and planners are used to provide advice for the amount of light that you expose yourself to and to help you alter your internal clock accordingly.

The majority of the advice that you find from these calculators are calibrated for an average person. However, there are certain points that should be considered such as:

  1. In the event that the time zone shift is more than eight hours, your internal clock could potentially advance or delay to bring you back to the new time. This frequently occurs more if you are traveling eastbound.
  2. Those individuals who sleep cycles are much later or much earlier than normal will find it easier to begin altering their internal clock in both directions.

If either of these scenarios apply to you, the normal guidance supplied by the jet lag calculators will not be as reliable. In both of these cases above, I do not recommend solely relying on the online planner.

I recommend that you take some to observe the two videos above and to create your calculations based on the guidance that is provided.

Jet Lag Program Comparisons

I searched and tried five different online calculators with guidance from two of the trips that were located in the researchers’ article from Rush University.

The advice that was provided in the article was based on very precise calculations. In turn, they are excellent standards to compare the calculators with one another.

This table displays the researchers’ advice for a flight that is departing from Chicago at 4:30 in the afternoon (Time In Chicago) and arriving in Paris at 8:30 in the morning (Time In Paris) the following morning.

DayFind Light (Paris Time)Avoid Light (Paris Time)
Arrival12:00pm to 4:00pm8:30am to 12:00pm
2nd Day11:00am to 3:00pm 8:00am to 11:00am
3rd Day10:00am to 2:00pm8:00am to 10:00am
4th Day9:00am to 1:00pm8:00am to 9:00am

Paris’ time is 7 hours in front of Chicago’s time, so you will arrive at 1:30AM in the morning.

The second trip in the list was from San Francisco to Beijing. In this instance, I altered the sleep time in San Francisco in the three days prior to the scheduled flight.

Out of the five calculators, these three work the best:

1. British Airways Jet Lag Advisor

Rating: 3/5

The British Airways Jet Lag Advisor only provides enough advice for two days, in spite of the number of time zones that have been traveled across.

This calculator is fine to use for one day, however the second day assumes that your internal clock has adjusted to more than what is feasible.

The information from the San Francisco to Beijing flight did not fair any better results and once more only covered a total of two days. In all, I do not have enough belief that this advice will change your jet lag experience.

British Airways Jet Lag Calculator Diagram.

2. Hillarys Jet Lag Calculator

Rating: 4/5

The Hillarys Jet Lag Calculator is very user friendly and it produces moderately accurate advice that is simple to understand.

Nonetheless, it only provides advice for the three days prior to arriving despite the amount of time zones that you have traveled across.

This calculator is the same as the other calculators due to the fact it presumes that you can alter your internal clock quicker than what the researchers believe is normal.

The do offer some widespread advice for changing your internal clock before you depart, yet this is not based on your specific flight. In all, it is a very good calculator when you arrive at your destination, yet is not nearly as useful as the Rooster calculator below.

Hillarys jet lag calculator screenshot

3. Jet Lag Rooster

Rating: 5/5

Out of all five of the calculators that are available, the Jet Lag Rooster is the most accurate. It is very user friendly and provides you with the option as to when you want to begin the adjustment whether that is prior to the flight, during the flight, or on arrival to your destination.

The advice that was provided by this calculator were very close to the calculations made by the researchers’ of Rush University. The calculator’s suggested times to seek and avoid light for the Chicago to Paris flight were nearly the same as the times the researchers indicated.

The time period was only slightly different for the San Francisco to Beijing flight.

In all, the calculations that were completed in order to find to the optimal times to seek and avoid light were near each other and the differences were not drastic.

Rooster Jet Lag Calculator.

Glasses and Lightboxes

There is research that proposes that exposing yourself to a source of strong light at an appropriate time is a catalyst to shifting your internal clock.

Athletes frequently utilize this information. An example of using a strong light source to avoid jet lag is the Los Angeles Dodgers when they were located in Australia.

The best source of strong light is natural sunlight. However, there are times when the weather conditions can be stormy, rainy, cloudy, or snowy.

There is also the possibility that you cannot go outside in the sunlight when you need to. Fortunately, there are alternative methods such as using glasses and lightboxes.

A number of these devices are quite costly and are not always suitable for travel. Yet, there are some more portable and cost friendly options such as:


These visor light glasses were created to help deal with seasonal affective disorder or more commonly known as the “winter blues”. This handy device with provide you with the strong light you need when traveling.

The manufacturer also states that the more focused concentration of light on the eyes helps minimize the amount of time that you need to use them when a lightbox is compared to it.

Luminette glasses

Re-Timer Glasses

These re-timer glasses have received much publicity from the press as stated by the manufacturer.

These useful glasses were created to be used when you should be finding a strong light source. The benefit of these glasses is that they have no UV green light, which in turn helps shift your internal clock to a preferred time.

Re-Timer Glasses

Sunrise System Light Box SRS 320

This is a company that specializes in creating portable light boxes in order to help defeat jet lag.

Due to strong light that this light box produces, it decreases the amount of time that you need to use the device. As a bonus, there are also alarm settings for a sunrise and sunset.

Sunrise System Light Box SRS 320

Aurora Light Pad Mini

Alaskan Northern Lights is an online retailer that designs and manufactures light boxes and other lighting equipment that helps other combat seasonal and non-seasonal depression, bipolar disorder, and other sleep disorders.

Although, it is not specified these lightboxes will help minimize jet lag as they work on the same principle as the other lightboxes.

The benefits of this light box is that they are portable, lightweight, and you can control the intensity of light this box emits.

Aurora Light Pad Mini 


Lumie is a company that manufactures a variety of different wake up lights and lightboxes and are supplied to the United Kingdom National Health Service.

Their website recommends that their Zest light box can be used for a plan to help eliminate jet lag.

Lumie Lightbox

Methods To Minimizing Travel Fatigue

When embarking on a long voyage it is natural to feel travel fatigue, even if the time zone change is small. An example of this would be traveling from the United States to Central America.

Fortunately, there are measures that you can take to help deal with travel fatigue before you go on your trip. These measures certainly will not adjust your internal clock. Nonetheless, they will help you feel more relaxed and well rested.

Measures To Take Before Your Voyage

  • Do your best to be as well rested as you can in the days that lead up to your scheduled trip. If you work yourself to the bone and take a trip while feeling exhausted, you will discover that it can take more time to recuperate or conquer the jet lag that you may encounter.
  • Schedule some time to exercise or do some form of physical activity the day before leaving for your trip. It is also to your benefit to exercise the morning before your flight, if you plan on traveling later that same day. I recommend that you avoid any type of demanding exercise near your flight time if you plan on sleeping on the airplane. Exercising this close to your flight time will only keep you awake and make it more difficult to unwind.

Pair of dumbbells.

Tips To Help You On Your Voyage

  • Drink a sufficient amount of water. Avoid consuming beverages that contain a lot of sugar, caffeine or alcohol. Bring or buy some water with you before or during your trip.
  • Pack some sleep devices such as a travel pillow, a sleep mask, or a travel pillow. All of these accessories will help you sleep sleep easier.
  • In the event of a layover in flights, you should use this chance to move around and get your heart rate pumping. If you have shower facilities available, taking some time to wash up can help you sleep easier prior to your next flight.
  • If you have made the decision to utilize sleeping pills on your flight, please do keep in mind that they can potentially make you feel dazed on upon waking up.
  • I recommend that you make an attempt to sleep naturally on your flight. Sleeping naturally is beneficial because you feel more refreshed upon waking up and you will avoid that dazed feeling that can potentially happen after consuming sleeping pills.


Does Melatonin Help?

This particular hormone receives much attention due to the fact it is seen as a more “natural alternative” as opposed to conventional sleeping pills.

The researchers from Rush University elaborate on how melatonin can assist with jet lag in two techniques:

  1. Consume a 3 mg dosage prior to your bedtime for the first few nights after an eastbound flight. In this instance, the melatonin is helping you go to sleep when your body is signaling you to wake you up.
  2. Consuming a smaller dosage of 0.5mg two to three hours prior to the scheduled time that you are supposed to go to sleep in a different time zone. This is approximately the time that your body will naturally produce melatonin and taking the small dosage will help you unwind further.

Final Thoughts

In spite of the fact that there is no cure for jet lag. At this point you are now aware of the fact that there are steps that you can take in order to minimize how long you experience jet lag for.

The important aspect to defeating jet lag is to alter your internal clock so that it correlates to the new time zone. It is important that you understand the role that light plays and how it affects your internal clock when traveling from one time zone to next.

The methods that will help you out are calculating how much time you are exposing yourself to light, what time you go sleep and the JetLag Rooster Calculator will help you create a plan of action.

Upon arriving to a new destination, you are now equipped with a plan that will help guide your internal clock without ruining your trip. Having your sleep patterns disrupted during a trip can make anybody feel cranky and that is something that you want to avoid.

Taking the necessary measures in order to adjust your internal clock before you leave for you trip will benefit you greatly as you will be able to sleep better throughout the entire duration of your trip. In some instances, there is a chance that you can avoid jet lag altogether.

Always remember this phrase “Failing to prepare is preparing to fail”. I can tell you from my own experience that taking the time to do the preparation work before any event will give you peace of mind and will not make you feel frustrated in the end. After all, nobody needs frustration to ruin their trip.

Food Preparation.
The key to success is in the prep work.

What is experience with jet lag?

What can you add to the list of resources to help others?

Please share your thoughts in the comments section below.


  1. Eastman, Charmane I. Ph.D., Burgess, Helen, J, Ph.D. (2009). How To Travel the World Without Jet lag 4(2): 241-255
  2. Ruscitto, C, Ogden, J. (2017) The impact of an implementation intention to improve mealtimes and reduce jet lag in long-haul cabin crew. 32(1): 61-77
  3. Dodgers Nation, Dodgers News: Team Using LED Light To Avoid Effects of Jet Lag (2014, March 17). Retrieved on July 27th, 2018.
  4. Mayoclinic (2018, September 11). Jet Lag Disorder. Retrieved on (2018, July 27th).
  5. Photo Credit: Pexels, Pixabay and Unsplash

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4 Comments on “How To Reduce Jet Lag – Methods To Adjusting Your Internal Clock In Different Time Zones”

  1. Hello Funshel,

    Yes, I agree jet lag does indeed pose a challenge to all of those who travel across many different time zones all at the same time. It is a disorder that many people have some familiarity with. I wanted to educate others further on what exactly jet lag is. That is great that you have gained a better understanding of the role that light plays. The cycle of daylight and darkness does affect your sleep patterns to a great degree.

    Best regards,
    Kenny Tang

  2. Hello Dianne,

    I am glad that I was able to convey this topic to you in a manner that was easy to understand. It is great that you are making an effort to go outside in the daylight. This action will help out tremendously when you are readjusting your internal clock. That is excellent that you are reading about melatonin. It is one of the primary hormones that promote relaxation and helps many people go to sleep at night easier.

    If you would like to learn more about your internal clock and its functions. You should take a look at my article about the circadian rhythm.

    What Is Your Circadian Rhythm? – The Function Of Your Internal Clock.

    Best regards,
    Kenny Tang

  3. Jet lag is a great challenge to the entire body system as it takes much time to adjust having traveled across multiple time zones. This blog post helped answer a question I do ask if one could ever travel across multiple time zones without jetlag. 

    Now I know the role light plays and how it affects the internal clock when traveling.

  4. This is a really good explanation of why we get jet lag and it effects on your own clock. This is something that we know happens, but I like the way you lay it down in layman’s terms. This really helps me to understand it and help set it right.

    Definitely going to take your advice and getting out in day light as much as I can to help adjust my own internal clock. I read about melatonin recently, so this is a fantastic tip going by what I learned about it.

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