Conquer jet lag with light and melatonin

Post Overview
    Add a header to begin generating the table of contents

    In this video from MedCram, Dr. Seheult discusses how to overcome jet lag with light and melatonin. It is important to know when to expose your eyes to bright light and how to use melatonin to help conquer jet lag.

    How does circadian rhythm play a role?

    To understand this fully, it is important to understand how the circadian rhythm works and why we get jet lag. Much of the jet lag that occurs is when people travel from west to east otherwise known as eastward travel. Things that happen in the human body are timed very specifically around the clock due to the circadian rhythm. This is timed with light exposure so that the body can differentiate between daylight and night. There are many cues from the environment that tell us what time it is. The master clock for the circadian rhythm is found in the suprachiasmatic nucleus. The most effective cue for the circadian rhythm is light exposure. Light is known as a zeitgeber. This is any external or environmental cue that entrains and synchronizes an organism’s biological rhythms, usually naturally occurring and serving to entrain to the Earth’s 24 hour light/dark and 12-month cycles. When what is happening internally i.e. the circadian rhythm is in sync with what is happening externally i.e. day/night cycles, then everything is usually fine. We will want to sleep when it’s dark and eat and be active when it’s light. If you were to expose yourself to light earlier in the daytime, your circadian rhythm will try to sync itself back into rhythm and you can start to see an advancement of the circadian rhythm.  This means the body’s cycle will occur earlier in the day. For this to happen, you need bright light in the morning and need to make sure not to expose yourself to bright light in the evening. If you expose your eyes to bright light in the evening, then you will delay the circadian rhythm. 

    How does melatonin affect the circadian rhythm?

    There is one other zeitgeber that is powerful and that is melatonin which is produced by the pineal gland. Light shuts down the production of melatonin. If you were to give melatonin in the evening it would also have the effect of advancing the circadian rhythm.  So to advance our circadian rhythm we must expose our eyes to bright light early in the morning and avoid light at night and melatonin could be added in addition at the end of day.  But if you want to delay the circadian rhythm, then you would not want any light exposure in the morning and you would want light exposure at night i.e. working at a computer. 

    How can I apply this to me when traveling eastward?

    So to use an example of getting on a plane in Los Angeles, California and traveling to London, England, there is an 8 hour time difference between the two destinations. In this particular example you are going ahead in time by 8 hours. The circadian rhythm at this point has not changed and while it may be 6 am in Los Angeles and now 2 pm in London, your circadian rhythm will start the activities at 2 pm in London that it would have done at 6 am in Los Angeles.  What needs to be done to get the circadian rhythm synchronized with the new time zone?  The easiest thing to do will be to advance the circadian rhythm.  The light exposure you will want to have should be at 2 pm in London which is 6 am in Los Angeles on your old circadian rhythm.  In London, you will not want to get any light exposure in the early morning and instead work on exposing your eyes to bright light in the early afternoon.  If you expose your eyes to light earlier in the day, you will have a harder time catching up to London time.  What is the recommendation?  Put dark glasses/sunshades on in the morning from 6 am to noon to not get a lot of light exposure.

    How do I use melatonin to help?

    The other thing that is helpful will be to take melatonin. This study had a protocol on how to alleviate jet lag with using melatonin. This randomized double controlled blinded study took 17 volunteers and flew them from San Francisco, California to London, England. They had the volunteers take 3 days prior to travel, 5 mg of melatonin at 6 pm San Francisco time vs placebo and then upon arrival to London for 4 days, take 5 mg of melatonin between 10pm and midnight London time vs placebo. They were then asked to rate their jet lag on a 0-100 scale with 50+ being considered positive symptoms. The study found that those persons taking placebo had more significant symptoms of jet leg compared to those who had taken the melatonin. Those that had used melatonin didn’t have any significant jet lag symptoms. It is important to note that if you are going to use melatonin that you purchase it from a brand that has been third party tested. You also do not want to use timed release melatonin. Other studies have shown that the dose of melatonin is probably not critical as this study showed that daily doses of melatonin between 0.5 to 5 mg were similarly effective. The timing of the melatonin of the dose is important because if it is taken during the wrong time such as early in the day it is liable to cause sleepiness and delay adaptation to local time. Melatonin use for short term appears to be safe but it should be use with caution in individuals with epilepsy and in those taking warfarin. 

    What about westward travel?

    What about westward travel? The circadian rhythm is actually a little longer than 24 hours, and the normal situation is for the circadian rhythm to delay itself.  As we travel westward, our external clock will be delayed and now the circadian rhythm needs to be delayed also. So westward is easier because normally when you want to avoid exposure to bright light, it is already nighttime at the new destination and when you want exposure to light it will be daytime at the new destination usually.

    Recommendations to crush eastward jet lag  

    In a nutshell, for eastward travel you will want to expose yourself to bright light for 6 hours (start at 6-8 AM in the morning and add the number of time zones you have passed through to get the time at new destination) and avoid bright light for six hours by starting at night 8-10 pm and add the  number of time zones you have passed through.  So for a time zone that is 8 hours ahead you would add 6+8 hours and this would get you to 2 pm in the new time zone. So likewise for a time zone 8 hours in advance, to avoid bright light you would start at 10 pm and add 8 hours. This would give you a time in the new time zone to avoid bright light i.e. from 6 am to 12 pm.  After each night you would reduce the new time zone hours by 1-2 hours.  You would also start with melatonin at 6 pm in your home time zone for 3 days prior to travel and then take melatonin at 10 pm to 12 am in the new time zone for 4 days after arriving. 



    Jet Lag (P & T) |… 

    Alleviation of jet lag by melatonin: preliminary results of controlled double blind trial (BRITISH MEDICAL JOURNAL) |… 

    Melatonin for the prevention and treatment of jet lag (Cochrane database of systematic reviews) |…


    Leave a Comment