Beating Jetlag
Performing with timezone changes
Jetlag seems to be one of those things that people seem to either really struggle with or feel they don’t struggle with - perhaps because it’s related to sleep and we see this pattern there as well. Most likely this is related to the strength and regularity of your circadian rhythm, or said more simply: how engrained your routine is.
What is Jetlag?
Fundamentally it jetlag is a misalignment between the time of day that your body clock (fun fact there are genes that help regulate body clock called, you guessed it, clock genes). There are clocks (with their own genes) in all parts of the body, they impact exercise capacity, digestion and many other processes - so this is much more than just a sleep issue.
Your body clock is more technically known as your ‘circadian rhythm’ (circa meaning “around” and dies meaning “day”) and is reset daily by a number of stimuli from the environment which give signals as to the time of day.
Enter Zietgebers
No, these are not the monsters that cause jetlag, they are “environmental time cues such as sunlight, alarm clocks, or social interaction that helps trigger an organism to entrainment to a 24-hour cycle.”
These cues are many but the big rocks are:
Light
Food
Exercise/Movement
For a fascinating study into deprivation of light check this out
Forward or Backward
The decision on which direction to phase shift is largely determined by the shift you are making (it’s rare to be making a 12hr shift where it’s a choice). That said, it’s much easier to extend your period of wakefulness than to shorten it, that is - if given the choice extend your day. This is probably multifactorial but my read on the situation is that it has two primary drivers: the human circadian rhythm (in absence of zeitgebers) is a little longer the 24hrs on average and drowsiness is driven by an accumulation of adenosine - we can fight that to an extent (hello coffee) but we can’t really induce it.
The Theory of Beating Jetlag
Summarised in a phrase I’d say “live on your destination timezone”. The extreme to which you take this will help dictate it’s efficacy and how quickly you can get on timezone (as will number of timezones crossed and your inherent strength of circadian rhythm of course).
So the goal would be to use the zietgebers to tell your body that it is on the timezone it is going to.
Light
Avoiding as much light as possible during the “night” of your destination timezone and getting as much as possible during the “day” of your destination timezone is probably the biggest factor in helping adjust your circadian rhythm. This is because of the body’s master clock being responsive to light through the eyes (if you want a technical answer the Huberman Lab podcast has done this to death and much better than I could). Again, this can get as technical and involved as you’d like - I tend that way due to my nature but the pareto principle (aka the 80/20 rule) is probably in play here. I go as far as covering all of my skin (and head) on flights to avoid light, also using an eye mask. The opposite is also true to gain light exposure. I will also get outside (no sunglasses!) on arrival to try and get as much sun as possible. Blue light is a wakening light - so you can use screens to your advantage to ‘waken’ you and conversely blue light blockers for times you have to be awake are likely helpful.
Likewise, once at your destination, some discipline around waking early, viewing natural light and avoiding night time blue light will be helpful.
Food
When thinking about food, we can think about any food as the primary factor and then what the food is, as a secondary factor. Food itself, works as a wakening factor, but as the fact we have phrases like ‘food coma’ should give some insight into the fact that there’s some nuance here.
Generally eating during the waking hours of the destination timezone (ideally at your normal meal times) would be the advice. I tend to suggest a higher protein ‘breakfast’ and higher carbohydrate (again, shades of grey here) dinner for the small differences in their impacts on sleep/wake respectively. Some people in the space suggest fasting rather than eating in timezone shifting - my bias is against this (I get hungry) but it’s certainly an option and makes some theoretical sense, but we do need to consider a level of practicality here and this may not be practical for everyone (including athletes).
Exercise/Movement
There are a few considerations here, and perhaps the answer is “it depends”, but I tend to advise movement early in the day as a wakening signal. There’s an argument that exercising at your normal time of day is part of resetting your circadian rhythm but I’d argue it’s always a wakeful stimulus (to varying degrees - more intense is more wakening) so morning makes more sense to get on to timezone. Similarly the digestive and metabolic clocks being misaligned can cause some dysregulation of digestive processes (again - if you want detail there’s some great work out there on various podcasts like "Inside Exercise” and “Huberman Lab”) and exercise may serve to counteract some of these like insulin resistance.
Exercise is certainly an important part of shifting circadian rhythm but much like it’s an important part of health, it’s partner in crime is movement (or physical activity). That’s to say, moving more/being more physically active is a wakening signal that you should be trying to use in addition to exercise. Anyone trying to stay awake watching something like Netflix knows this, so keep moving as much as possible during the daylight hours.
Other Substances
Many of the experienced travellers are probably surprised they have not yet seen mention of melatonin. This naturally occurring hormone is a staple of jetlag protocols and many travellers swear by it. In short, there is a large pulse of melatonin released prior to sleep onset when our circadian rhythm is aligned, so whilst melatonin won’t make you particularly drowsy it has actions to help induce sleep as well as maintaining. Crucially it aids in resetting circadian rhythms as a result of it’s cyclical nature and role in sleep. Melatonin itself is a fascinating compound, with many longevity enthusiasts using more and more of it from a longevity standpoint. I personally use it to good effect for 3-5 nights depending on the number of timezones shifted. Doses are taken 30-60mins prior to onset of sleep, doses in the literature range from 0.5mg-5mg with some variance in reported efficacy about 0.5mg. Doses above 5mg are reported as no more effective than 5mg. A quick note here - some people experience some fairly florid nightmares so be weary if you’ve not used it, similarly not everyone experiences the benefits (Number needed to treat is two, so in short, two people on average need to use melatonin for one to see a benefit).
Caffeine is technically not a zietgeber (it’s a stimulant) but it certainly can play a role in your strategy. Specifically I would suggest using it in your normal caffeine consumption window with some modifications. Shorten your normal window if shortening your day - stop caffeine earlier than you normally would for example stop caffeine at midday or 1pm on destination time and perhaps use less caffeine. If lengthening your day, I would not go beyond what is normal for your caffeine consumption (in time or dose) but I would perhaps nudge it a little later, perhaps starting consumption a few hours later than you normally would (again reference point is destination timezone).
Alcohol, I am not a parent of yours. I am also no saint. But alcohol is bad for sleep and circadian rhythms, period. That thing you do when you’ve had your night cap on the plane, it’s called sedation, not sleep - they are different. Same story with sleeping tablets (which scare me endlessly from my time in hospitals - perhaps I will write an article on them one day).
Checklist for Beating Jetlag
Plan your shift ahead of time so that you can have everything in order, for example I carry high protein snacks and coffee packets (these are the best I’ve found) so that I don’t have to be dependant on plane food/coffee.
Start your timezone shifting as early as possible - each timezone you shift takes around a day to adjust to, so starting earlier gives you a head start. Waking up and going to bed an hour or two earlier for a day or two isn’t a huge imposition for most folks.
Use the zietgebers on the destination timezone - live your life as much as possible as though you’re on the desired timezone.
Caffeine is your friend and alcohol your enemy (sedation is not sleep).
Watch vs Phone - this is something most are surprised by, but the psychological effect of ‘knowing the time’ is huge. So set your watch to your destination/desired timezone and use your phone for making sure you don’t miss flights etc, keeping it on the current timezone.
Ideally travel early enough (and use point 2) so that you have time to adapt to the desired timezone for performance be it mental or physical.
If you can’t do number 6, try make sure that the performance is during an overlap in wake times for the two timezones ie morning for one and afternoon for the other or similar.
In terms of the logistics of planning all of this I personally use a spreadsheet and offset the two columns with time difference. This is somehting I have done for a few friends too. If you travel a lot and want something less work intensive, there are apps like timeshifter which look to do this (I have not used it personally).
Let me know in the comments how this worked for you or if you have any other suggestions.
References:
Duffy JF, Czeisler CA. Effect of Light on Human Circadian Physiology. Sleep Med Clin. 2009 Jun;4(2):165-177. doi: 10.1016/j.jsmc.2009.01.004. PMID: 20161220; PMCID: PMC2717723.
Sadowska-Bartosz I, Bartosz G. Effect of antioxidants supplementation on aging and longevity. Biomed Res Int. 2014;2014:404680. doi: 10.1155/2014/404680. Epub 2014 Mar 25. PMID: 24783202; PMCID: PMC3982418.
Stacchiotti A, Favero G, Rodella LF. Impact of Melatonin on Skeletal Muscle and Exercise. Cells. 2020 Jan 24;9(2):288. doi: 10.3390/cells9020288. PMID: 31991655; PMCID: PMC7072499.
Herxheimer A, Petrie KJ. Melatonin for the prevention and treatment of jet lag. Cochrane Database Syst Rev. 2002;(2):CD001520. doi: 10.1002/14651858.CD001520. PMID: 12076414.
Potter GDM and Wood TR (2020) The Future of Shift Work: Circadian Biology Meets Personalised Medicine and Behavioural Science. Front. Nutr. 7:116. doi: 10.3389/fnut.2020.00116