What is Jet Lag?
Jet lag is when your body’s internal clock is still operating on the time zone from which you came although you’re now in a new time zone. So, for example, say you leave Toronto, Canada (Eastern Standard Time, EST) and go to Rome, Italy (Central European Time, CET). When you arrive in Rome, say at 9 am CET, your internal clock still thinks it’s 3 am (because it’s still 3 am in Toronto). So, although it’s morning in Rome, you still feel sleepy because your body thinks it’s still overnight. Jet lag is a temporary normal physiological condition. The main symptoms are sleepiness, fatigue, and reduced performance. It is most commonly experienced in those who travel across three time zones or more.
How do you set your internal clock?
Your internal clock is regularly calibrated to your environment’s clock via “zeitgebers”. These are environmental time cues, sort of like road signs letting you know that you’re approaching your target destination. The most powerful of these cues are ambient light and darkness. But, also, things like sleep schedule (i.e., naps will disrupt this), meal timing and the types of activities you do at certain times of the day.
Can you do CBT-i even though you expect to travel across time zones soon?
You can, but you’re better off doing Cognitive Behavioural Therapy for Insomnia (CBT-i) training when you are not expecting to travel. If you decide to embark on CBT-i even though you will be travelling across time zones during your training, you should do so with one-on-one help from a sleep consultant. There is a chance you will have to do it again when you plan to be in a time zone for at least 12 weeks.
Is there more than one approach to setting your internal clock to the new time zone?
Here are three general approaches:
Scenario 1 – Prepare ahead of time
You can try to start syncing your internal clock to the new time zone a week or two before you leave for your new destination. This may be an attractive option if your schedule is flexible and you are planning to travel for a short time. This will allow you to adapt faster to the new time zone allowing you to get more out of your short trip. This also may be attractive for people who are sensitive to time changes and they find it takes them a long time to adapt.
Scenario 2 – “Cold Turkey”
You can follow the tenets of CBT-i once you land in your new destination. This is the most popular approach and the most efficient.
Scenario 3 – “Leave well enough alone”
Some people, may find it acceptable to just live according to their internal clock in the new time zone. So, in this example, it’s less likely that going to bed at 4 am and waking up at 10 am would be socially desirable. But, if they were only travelling 3 hours ahead, a bed time of 1 am and a rise time of 8 am may be acceptable, especially if the duration of your trip is short and your going for fun and socializing rather than work.
How would Scenario 1 work?
So, going back to our example, say you plan to go to Rome in 6 weeks time. You know that Rome is 6 hours ahead. You currently go to bed at 10 pm and get up at 5 am (for example). You look at your schedule and you believe you can still satisfy your obligations with a sleep schedule from 1 am to 8 am). You also notice that this is still 3 hours behind CET (the time in Rome) but it will lessen the impact of Jetlag, i.e., you’ll have to only acclimatize your internal clock for a 3 hour time difference (rather than 6 hours). As such, you may aim to slowly delay your bed time by 30 min every week for 6 weeks. Of course, you would still follow the principles of sleep hygiene, stimulus control, relaxation and stress management.
How would Scenario 2 work?
Scenario 2 just involves following the principles of CBT-i for your new time zone. You can at times employ a little flexibility in helping ease the transition.
So, let’s assume you are landing in Rome at 9 am CET (coming from Toronto where it is currently 3 am EST). Since your internal clock feels like it’s 3 am, you’ll likely feel sleepy. However, you want to adapt to Rome time. So, do not sleep. You will start doing things to train your circadian rhythm to be Italian.
1. Expose yourself to sunlight.
Upon landing, during daytime in Rome, make sure you expose yourself to sunlight.
2. Stay busy during the day.
Plan to do active tasks that are stimulating like exercise, setting up your apartment, doing necessary errands, seeing relatives, appointments with lawyers/government offices, etc. Basically, you want to do activities that are the opposite of the kinds of activities you would do if you were to wake up overnight (i.e., activities that are not too stimulating so that you increase your chances of falling back asleep). So, you would not want to do passive activities like watching TV or movies, long bus rides, etc. The chances of nodding off during these activities are high.
3. Manage pre-bedtime light levels.
Avoid light and/or wear sunglasses for about 4 hours before your desired bedtime (e.g., 10 pm CET). This begins on the flight. So, bring a sleep mask, ear plugs, blanket, neck pillow or whatever you need to stay comfortable.
4. Aim for your usual bedtime but in your new environment.
So, in this example, you would be aiming for a bedtime of 10 pm. Here, you may be a bit flexible and go to bed at 9 pm (for example) if you are really tired because your sleep deficit is likely higher than normal and you could likely sleep that extra hour (rather than spending that extra hour awake in bed, something that is not desirable). You would still keep up – to the best of your ability – all the tenets of CBT-i like sleep hygiene, stimulus control including your wind-down routine.
5. Keep an anchor time.
This is the time you are going to wake up and get out of bed, even if you’re still sleep. So, say in Toronto you were sleeping from 10 pm to 5 am EST. In Rome, you would set your alarm for 5 am CET. Remember, if you’re still sleepy, that sleep deficit will not be lost. It will improve the chances of better sleep the next night.
You would then keep up the same principles (i.e., CBT-i) principles.
The person in Scenario 1 would follow this same approach to make up the 3 hour time difference they experience (since they pre-adjusted their circadian rhythm to be 3 hours closer to Rome time while still in Toronto).
There are other things you can do to help minimize the effects of jet lag like optimizing your health before travel, staying hydrated, avoiding alcohol (part of sleep hygiene) and taking measures to avoid getting an infection. Getting sick during air travel is common and can make tackling jet lag more challenging.
Can I nap?
If you feel like you must nap, try to keep your nap before 1 pm CET and keep it short. That is, keep it less than 45 minutes but ideally even less than 30 minutes as some people can go into deep sleep in just 30 minutes. If this happens, you may find it harder to be disciplined and wake up. You will also likely feel sleep inertia which can be uncomfortable for some people and make you more fatigued. Make sure you have an alarm and maybe even employ a plan B, like scheduling a wake up call. You will still likely feel sleepy and tired when you’re done your nap. However, you want to preserve that sleep deficit to increase your sleep drive for a normal bedtime in Italy.
Is it easier to adapt to going east? or going west?
Generally it’s more challenging to adapt to a time zone east of you. The reason is that you can’t force sleep. Sleep will come when it feels welcome. And, so, if bedtime in Rome (e.g., 10 pm) comes and your still not sleepy, you’ll have to wait until sleep comes, of course, following the tenets of CBT-i.
When you are going west, you have to delay your internal clock. So, say you’re in Vancouver (from Toronto) and 7 pm PST comes around (it feels like your bedtime, i.e., 10 pm EST for you), there are things you can do to stay awake for a few more hours until 10 pm PST. When travelling westward, you would expose yourself to light before your bedtime a little longer to shift your circadian rhythm. You could also avoid light and/or wear sunglasses upon waking up to also help delay your internal clocks rise time.
How long does it take to adjust your internal clock?
For most people, it takes about 1 day to adjust for 1 hour when travelling from West to East. So, it’s very likely that the majority of people could transition their internal clock from Toronto time to Rome time in a week. However, if your trip is only for one week, you may be better off selecting another destination in roughly your own time zone (if possible) so as to avoid the jet lag.
Adapting your internal clock to travel from east to west generally takes half the time.
Can I take melatonin?
Melatonin is a hormone that is naturally secreted by your pineal gland. The suprachiasmatic nuclei in your hypothalamus coordinates when this is secreted. In fact, it coordinates many physiological changes that support sleep like changes in core body temperature, hormone levels, brain wave activity, etc. Melatonin secretion requires darkness. Light intensity of >50 lux will start to inhibit melatonin secretion. Light intensity > 2000 lux will suppress it completely. As you can see, the principles mentioned above take priority in helping your physiology to do what is most welcoming to sleep.
However, if you wanted to use melatonin to help shift your internal clock, there are a few things to keep in mind.
1. How much to take?
It’s best to use a low physiological dose (0.1 mg to 0.5 mg). Most formulations available OTC are many times this. Also, because of differences in the regulation of products like melatonin vs. pharmaceuticals in Canada, sometimes the amount of melatonin in the supplement is many times more than what is advertised. There are some independent labs that assess the integrity of supplements e.g., National Science Foundation, Consumer Lab Testing, US Pharmocopoeia (USP). If a product contains a seal from one of these labs, it means that this lab endorses that the supplement is as advertised.
2. When to take it?
Timing is important. Melatonin taken orally works best in shifting your circadian rhythm when there is less of the melatonin that your body makes hanging around in your blood stream. So, for travelling from west to east, taking it about 5 hours before your desired bedtime will help shift your internal clock. For travelling from east to west, although it may seem counterintuitive, taking melatonin taking it in the morning (while wearing sunglasses) helps shift your circadian clock backwards. So, for example, say you’re travelling to Vancouver from Toronto. You may want to wake up at 8 am EST, which is only 5 am PST. So, from 5 am PST to 8 am PST, you will want to wear sunglasses. You may also want to take melatonin.
Generally, melatonin use like this shouldn’t be used for longer than a few days so that you don’t suppress your own body’s release of melatonin. Keep in mind that melatonin can have side effects, and its use may be limited by these side effects. You should only use melatonin under the guidance of a medical doctor. In fact, in the European Union, melatonin is only available by prescription.