To most travellers, jet lag is a familiar and unpleasant experience. While some of us have our own tried and true coping mechanisms, the rest of us can’t shake off jet lag for days or weeks. The key to preventing jet lag is to understand how light and travel direction – east or west – affect your internal clock.
When several time zones are crossed rapidly, your sleep-wake pattern gets out of sync with your circadian rhythm (a 24 hour internal cycle) which is primarily regulated by daylight. Air travel does not give your body enough time to cope with the disruption and adjust to the new daylight / darkness cycle of your destination. As a result, you either have to ‘speed up’ or ‘slow down’ your internal clock to match local time, which can temporarily affect your health.
Unfortunately there are few controlled scientific studies that have looked at jet lag. What we do know is that almost all travellers are affected by jet lag and most are affected by eastward travel (this is because you lose time and sleep). Frequent travellers can experience less jet lag symptoms over time while older persons and those with pre-existing sleep disorders can be more prone to jet lag.
Signs of jet lag include:
Symptoms of jet lag can intensify the more time zones are crossed. They usually start after a two-hour time difference and persist for one week or more. Typically, it takes one day to recover from one time zone change.
Jet lag can worsen pre-existing sleep disorders and psychiatric conditions, including anxiety and chronic stress disorders. Travel stress, disrupted sleep patterns, and travel at high altitude can also worsen pre-existing heart conditions.
Although jet lag can’t be avoided entirely when travelling across different time zones, you can minimize its impact with the following:
Adjust your sleeping schedule
Adjusting your sleep schedule before you leave is a common suggestion for preventing jet lag. If you are travelling from west to east, you’ll want to go to sleep one hour earlier each night at least three days prior to departure. This will allow you to mimic the time at your destination prior to your arrival. The same method is used if you’re travelling from east to west – you’ll want to stay up one hour past your bedtime to push your awake time by at least three hours by the time you leave.
Adjust your exposure to light
Another anti-jet lag measure is to maximize your exposure to bright light (preferably natural light) during the right time of day. Changes in exposure to daylight disrupt the production of melatonin, a hormone that regulates your sleep/awake cycle.
If you travel east, you’ll want to get as much light as possible from sunrise and into the early morning. This will help you to get in sync with local time. The opposite is true when travelling west – you’ll want to delay bright light exposure until late afternoon and early evening.
Doing this for a minimum of five hours a day for a period of three to four days will help readjust your circadian rhythm. You can minimize light exposure by shielding windows, staying indoors, and wearing sunglasses, and then maximize access to sunlight when needed.
Melatonin is a hormone produced by our pineal gland when we sleep. It helps regulate our circadian rhythms with the help of light exposure. Melatonin supplements are usually taken 1 day prior to your departure and continued 3 days after arrival. Alternatively, supplements may be taken at bedtime when you arrive at your destination and continued up to a week after.
Talk to your healthcare provider before taking melatonin, and if it’s safe for you (it’s not recommended for persons with cardiovascular or blood clotting conditions) get a prescription. Over-the-counter melatonin may not provide the adequate dosage, reducing its effectiveness. Also, the use of melatonin is unregulated in many countries, including the United States. Note that the effectiveness of melatonin varies among individuals and there are currently no studies that analyze the long-term safety of taking melatonin, including during pregnancy.
Sleep inducing medication
Common sleep inducing medications belonging to non-benzodiazepine class (ie. zolpidem, zaleplon, zopiclone, and eszopiclone) can offer short-term relief from insomnia, but do not readjust circadian rhythms. Check with your doctor if these types of medications are right for you and if they should be taken in conjunction with melatonin.
Side effects may include memory loss, excitability, and depression. Do not drink alcohol or take anti-histamines when taking these types of drugs. Due to the psychoactive properties of both nonbenzodiazepine and benzodiazepine drugs, some countries have banned their importation. Check the International Narcotics Control Board (INCB) website for country-specific restrictions. Note that this list is incomplete and you may need to contact your destination’s embassy, consulate, or Ministry of Health for more information.
At your destination
Information last updated: April 16, 2020