Jet Lag…Timing is Everything

HWN Team | Cutting Edge
Jet Lag…Timing is Everything

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Welcome to the jet age. On any given day millions of people suffer from jet lag. Can we minimize the curse of modern day travel?

The human body regulates our sleep-wake cycles with a built-in clock that adjusts to local environment cues with daylight being the most important. Whenever our body clock gets disrupted ‘jet lag’ can occur. 1
And you don’t even need to travel. People can suffer from jet lag or desynchronosis if their work schedule is suddenly changed. Even daylight savings time change can cause jet lag along with other living and/or working environments which do not follow the 12 hours of light, 12 hours of dark cycle such as undersea (submarines), underground (mines, tunnels), outer space and latitudes such as the Arctic or the Antarctic.
Air travelers who rapidly travel across multiple time zones (at least two) are the ones most likely to suffer from jet lag. And the more time zones a traveler crosses, the worse the following jet lag symptoms will be:

  • Sleep disorders (e.g. insomnia)
  • Tiredness at daytime
  • Lack of appetite
  • Fatigue
  • Grogginess
  • Disorientation
  • Reduced alertness
  • Inability to concentrate
  • Mild depression
  • Exacerbation of existing health conditions

Jet lag is generally a temporary condition whose symptoms disappear after a couple of days but the length and severity may depend on several factors namely: the distance, direction and number of time zones travelled, activities during travel and individual differences in susceptibility including age.

However, not surprisingly there are long-term health effects in people who constantly suffer from transient jet lag. A study of Indian male and female flight attendants revealed five major health problems:                   

  • Stress (88.85%)                   
  • Back pain (72.65%)                  
  • Loss of memory (67.47%)                 
  • Headaches (58.42%)                  
  • Loss of hearing (51.37%)

And a study on airline crews reported that trans meridian flights can lead to impaired physical and psychological health as well as cognitive deficits. 3, 4

So, what are the options to counteract jet lag?

Not much when it comes to airline personnel. Before they can adjust their biorhythms to the new time zone they move back or move onto the next one much like the ultimate jet setters, professional athletes and performers who travel from country to country or continent to continent to compete or perform. But for the rest of us there are three main options.

Behavioral modification - The good news is there are some decent apps to help you. Before you fly the Jetlag App and the Jet Lag Calculator can help you calculate your potential “lag”, adjust your sleeping patterns and can give you advice on light exposure and avoidance.

As soon as you board the plane, immediately adjust your watch to your time zone destination. Try to relax as much as possible during the flight. Keep yourself hydrated but avoid alcoholic and caffeinated drinks as both act as stimulants. Eat small healthy meals. Avoid high-salt high-fat food. Get up regularly to do some stretching exercise. Other suggested measures that may help reduce the effects of jet lag while inflight include: eye shades, ear plugs, noise cancelling headphones and neck rest pillows.

Upon arrival don’t take a nap especially if is after 3pm. Take a warm bath or shower then get out into the sunlight.  “Daylight is a powerful stimulant for regulating the biological clock whereas staying indoors worsens jet lag.” Exercise is also recommended but very strenuous physical activity. Adjust your mealtimes and sleeping times to the new time zone. Avoid large meals and high alcohol intake until your digestion and excretion routines are fully back to normal. 5

The upside is that behavioural modification may minimize jet lag but the downside is that it takes a lot of planning and time especially before flying which many of us may not be able or inclined to do.

Medications - A word to the wise: Although many over the counter sleep aids or prescription drugs may manage short term insomnia they do not resolve the biological imbalance of jet lag and they can have deleterious side effects including short term memory loss.

Then again there's melatonin  “In the human body, sleep is initiated during a rise in the concentration of melatonin (N-acetyl-5-methyoxytriptamine) and during the declining phase of body temperature. Synthesized from serotonin in the pineal gland, melatonin helps to shift human circadian rhythms. An increase in melatonin alerts the body that “biological night” is starting, whereas a decline in melatonin alerts the human body that biological night is ending." 6

Although there have been multiple studies looking at melatonin use for jet lag, there have been no double blind studies until Arendt et al evaluated 17 patients taking an eight-hour eastbound transmeridian flight. 

"Travelers who were randomly assigned to the melatonin group (n = 8) were instructed to take 5 mg/day starting three days before the scheduled flight in the early evening (at 6 p.m.) and for four days post-flight at the bedtime hour of the new local time zone (from 10 p.m. to midnight). Subjects receiving melatonin experienced significantly fewer severe symptoms (P = 0.009) based on subjective measures, including jet lag ratings, self-recorded sleep parameters, and mood ratings. Melatonin participants also adjusted more rapidly in objective measures, such as assessments of endogenous melatonin levels and cortisol rhythms...

In terms of improving symptoms of jet lag, little to no difference has been shown with various doses of melatonin ranging from 0.5 mg to 5 mg. Common adverse effects of melatonin have included daytime sleepiness, dizziness, headache, and loss of appetite. It is unclear whether these side effects are a result of the melatonin or the symptoms of jet lag itself. Travelers are also at an increased risk of experiencing hypnotic effects of melatonin at higher doses; as a result, lower doses are preferred for inducing phase shifts without side effects." 7

Current recommendations suggest that if a traveler crosses five or more time zones, melatonin should be taken on the day of travel at the projected nighttime hour in the new time zone and on subsequent days in the new time zone. And for seven to eight time zones, take melatonin one to three days before travelling. 8

Melatonin sounds like it should work yet only one double blind, albeit small, supports its benefits. And be aware that melatonin remains unregulated in most countries so you may not even be getting the proper or stated dose. Additionally the story on melatonin is not complete especially when it comes to messing with your own hormones.

Light therapy

Sunlight has a major effect on our circadian clock and when crossing time zones, our body needs to adjust to a new daylight schedule. Exposure to natural sunlight is the ideal mechanism to counteract jet lag.

“For those who travel frequently and are unable to have exposure to natural sunlight, light therapy may be a viable option. Light synchronizes the body clock by exposing the eyes to an artificial bright light that simulates sunlight for brief periods at planned times during the day. Various modalities include a light box, a lamp, and a light visor.” There is also some evidence that combining melatonin and light therapy at appropriate times can mitigate the symptoms of jet lag. 6, 9

The light therapy proponents may be onto something but most of the data is anecdotal, and the cost of the lights could fly you across at least 12 time zones!

The Bottom Line

There is no easy fix or else by now that magic potion would have been discovered. 

For people who frequently move from one time zone to the other it’s not even worthwhile to try and adjust. And behavioral modification and light therapy before flying may end up being more stressful than jet lag itself plus who has the time especially before departure.

Taking melatonin appears to be promising and is probably worth a try, although the jury is still out. Then again taking that warm bath after arrival sounds good and staying up until the time zone's bedtime hour may work for most of us.

What’s the ultimate cure: Don’t fly. Timing is Everything!  


  1. About Jet Lag,
  2. Sharma L, Lifestyles, flying and associated health problems in flight attendants, J R Soc Promot Health, 2007 Nov;127(6):268-75
  3.   Ariznavarreta C et al, Circadian rhythms in airline pilots submitted to long-haul transmeridian flights, Aviat Space Environ Med, 2002 May;73(5):445-55
  4. Cho K et al, Chronic jet lag produces cognitive deficits, J Neuroscience, 2000  Mar 15;20(6):RC66
  5. Jet Lag and Sleep, National Sleep Foundation
  6.  Mary Choy et al, Jet Lag, Current and Potential Therapies,  P T. 2011 April; 36(4): 221-224, 231
  7. J Arendt et al, Alleviation of jet lag by melatonin: preliminary results of controlled double blind trial, Br Med J (Clin Res Ed). 1986 May 3; 292(6529): 1170. 
  8. Srinivasan V, Spence DW, Pandi-Perumal SR, Trakht I, Cardinali DP. Jet lag: therapeutic use of melatonin and possible application of melatonin analogs, Travel Med Infect Dis. 2008 Jan-Mar;6(1-2):17-28
  9. About Light Therapy, Litebook

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