With travel being such a big part of contemporary life, many of us have now experienced one of the most unwelcome consequences associated with crossing time zones -- jet lag. While even an hour delay or advance can cause grief, the effects of jet lag really begin to manifest when crossing at least three time zones. This is when falling asleep and waking up on time really does become a challenge.
Why three hours?
That would be because, at three hours, your circadian rhythm will not align well with the normal daily schedule at your destination.
Let's say that you are in Ottawa and have to travel to Seattle, which entails crossing three time zones. In this case, there will be a three-hour time difference, which means that if you normally go to bed around 22:00, you will begin to feel sleepy at around 19:00. So, you would essentially be wanting to go to bed when it's roughly dinnertime in Seattle. If you were to fly to a destination that was only two time zones away, like Calgary, the local time would at least be 20:00 and some locals would be starting to wind down for the evening at 21:00, so the shift in time zones would not necessarily be as challenging.
Likewise, imagine that you are heading east, from Seattle, and you need to wake up for an 9:00 meeting in Ottawa. The three-hour time difference would mean that the meeting is taking place at 6:00 in the morning for you, as your body has not quite adjusted to the new time zone yet. I don't know about you, but I do know that 6:00 would be an ungodly hour for a morning meeting for many people. At a two-hour time difference, you'll still feel the impact but at least it's 7:00 (still ungodly if you ask this night owl).
Chronotype and jet lag: When time change actually helps!
There is an interesting thing that happens, though, when your chronotype is that of an extreme night owl or an extreme morning lark. Travelling three hours west for a night owl actually has its benefits because it means that your internal clock, which would be delayed by at least three hours, will not have adjusted to the local time yet. This means that you're internal clock will actually align well or better with the 9-to-5 norm at your destination locale. So, that 9:00 meeting would be like going to meeting at 12:00 at your location of origin. Not bad! Believe me. I know about this first-hand. Alas, this is a temporary thing that happens when social jet lag and jet lag actually work together to create an amazing sort of alignment with the 9-to-5 world in which night owls don't usually fit.
Imagine, too, what an extreme morning lark would experience heading east to New York, let's say. For once, they'll have enough energy to make it through a night out on the town! I am not saying this with ironic intent, although I do find it amusing (why? because it is so not my experience).
Research estimates that fewer "extreme morning larks" exist than extreme night owls, but I have known a few. These are the people who wake up at 4:00 and go to bed at 20:00. While their work lives are fine, their social lives are often non-existent or challenging, because they need some shut-eye at the precise time when others are out on the town for dinner or a movie. Now, when travelling east, they'll actually be able to enjoy that movie without falling asleep in the theatre because a movie that starts at 20:00 (local time) will feel like 17:00 for them. Interesting. Right?
So, when thinking about jet lag, factor in your chronotype, too. Although not many people talk about it and how it affects actual jet lag (not social jet lag), chronotype does play a role.
Most of the time, though, jet lag is brutal
Regardless of chronotype, though, jet lag is not easy. Any misalignment between your body clock and a new time zone will be tough and will affect when you sleep, eat, work, and play.
Let's not forget about sleep deprivation
However, one thing people forget to factor in when talking about jet lag is that it is often accompanied by the effects of sleep deprivation, depending upon when you schedule your flight and how long it will take for you to travel to your destination. This combination of sleep deprivation and jet lag is especially challenging, and it can wreak havoc on your sleep and circadian rhythm in all sorts of ways. I know this all too well, considering that long-haul flights have caused major disruptions in my own sleep/wake schedules and sleep loss when travelling. I can imagine that the same could be said for many of you.
So, what can you do about jet lag?
Start adjusting to your destination's time zone before your trip
If you know that you are going to be crossing time zones, calculate the time difference between where you currently are and your destination and determine whether you will need to advance or delay your sleep/ wake times. There are two things that you can do to make the transition easier: (a) expose yourself to bright light and/or (b) take melatonin.
Researchers have found that you can advance your sleep/wake times by about 2 hours when you expose yourself to bright light (e.g., sunlight) in the morning, as soon as you wake up, and when you take a small dose of melatonin in the evening. Other researchers have also used various forms of light avoidance in the evening as well. In a future podcast (yes, we're going to have a podcast!), we'll go into one of these studies in more detail for you. If you can't quite wait, have a read:
To delay your sleep/wake time, do the opposite. Expose yourself to bright light in the evening and/or take a small dose of melatonin in the morning, although be mindful that melatonin may make you sleepy. So, bright light alone in the evening might be the more practical option. If you do take melatonin, we advise that you do consult with a health practitioner, even though it is a supplement that you can buy over the counter. Also, know that it's easier to adjust to a delay in your bedtime than to advance it. So, if you are travelling in a westward direction, the adjustment is typically easier.
Break up a long trip into shorter trips
While this is not always feasible, I am seriously considering this strategy for myself for my next long-haul trip. Basically, I think I might break up that trip into two or three smaller trips, where I stay in one location for a few days to ease the transition to the time zone at my final destination while limiting the effects of sleep deprivation.
Adjust your watch to the time at your destination while on the plane
Adjusting the time on your watch on the plane is one of those tips that you will read about everywhere, and there is something to it. An issue with it may be that other people on the plane, especially when dealing with transfers, may be flying to different final destinations, thereby making this tip somewhat challenging to implement. For instance, you may be wanting to stay awake and let in the sun, whereas the person next to you may be wanting to go to bed and shut out the sun. Still, I have tried it, and it keeps me somewhat aware of the time as I cross the time zones.
What are your tips for dealing with jet lag? Please do share; we would love to hear from you.