Be a Boss in Any Time Zone
The science behind jet lag and rapid re-adjustment strategies for an optimal performance.
In a nutshell:
· Jet lag is a collection of symptoms which occur as a consequence of rapid travel across time zones.
· Circadian rhythm is the body’s internal timer or clock which regulates a host of bodily functions.
· Normally the body clock is in sync with the day-night cycle of the local environment.
· In a new destination, the body clock must go through a re-adjustment period as it adapts to the new time zone. This re-adjustment causes the symptoms of jet lag.
· The length of time it takes to recover from jet lag depends on the number of time zones crossed and the direction of travel (east or west).
· Several adaptation strategies including light therapy, melatonin, timing of exercise, diet and meals can be used to create a rapid re-adjustment period for optimal performance.
· The best solution is to use these strategies in a pre-adaptation phase before departure and an adaptation phase on arrival at the destination.
Everyone’s performance fluctuates from day-to-day depending on factors like mental state, physical state and the external environment. Jet lag is a consequence of rapid travel across time zones brought about by an internal body clock that is out of sync with circadian rhythms. Today as jet plane travel has become a normal part of life for many people, its become an important consideration in peak performance.
This isn’t for the guy going on a beach holiday, this is for the gal landing in a new time zone for a job interview, important presentation or meeting, exam or a sports event. It is vital that in these instances that they are on top their game and able to perform immediately.
So is it possible to rapidly travel across time zones and maintain the level of performance you achieve in your native environment? To understand what’s going on behind the scenes let’s first explore the circadian rhythm or body clock.
The circadian rhythm is the body’s internal timer or body clock. It is an incredible orchestra of hormones and neurotransmitters (brain chemicals) that flow through the body on a strict schedule. It controls the timing of many bodily functions including blood pressure, heart rate, temperature, toileting, alertness, tiredness etc. Under normal conditions, it is synchronised to the external light-dark conditions. So as the seasons change and light- dark periods change, so do our body clocks. This is less true in the modern world as we have introduced artificial light to take control of our environment.
If we suddenly change time zones, the circadian rhythm becomes out of sync with the new location. Daylight and darkness occur at different times than what we are attuned to and the body has to go through a re-adjustment period. This is when we experience the symptoms of jet lag.
What happens when you are jet lagged? We all know that feeling jet lagged sucks!Effects include poor cognitive performance, decreased concentration and coordination, poor memory recall, fatigue, headaches, apathy and irritability. Physical changes like poor athletic performance, changes in regular body habits like going to the toilet and reduced enjoyment or interest in food also occur.
How long till you recover? Studies have shown that the fastest rate of adaptation is half a day per hour of the time difference when travelling west, and one day per hour of the time difference when travelling east. So if you travel east from Rio to Vienna, which has a 3 hour time difference, it will take 3 days to adjust completely. But this is an average based on population studies and everybody’s adjustment times will vary slightly. Some people naturally recover rapidly and experience little disruption while others will take much longer. All of us however, can minimise the impact of jet lag on performance by implementing the strategies suggested in this article.
Flying East: This is where it gets a bit complicated so work with me through this. When you fly eastwards you go ‘forward in time’. You land at your destination at a time that is later than it would be at home. Therefore you have lost hours and are now further ahead in time than your body thinks it is. Your body clock is still on the time of origin where you began your journey. For example, it could be 10pm at your new destination but your body still thinks it is 6pm from the origin of journey clock. The issue with flying east is that it is difficult to fall asleep at the right time. In order to adjust your body clock to flying east you need to ‘advance’ it. We’ll come back to exactly what this means.
Flying West: When you fly west you ‘go back in time’. You have gained hours and therefore have a longer day. You are further back in time than the place of origin where you began your journey. This means it is earlier than your body thinks it is. For example, it could be 7pm at the destination but your body still thinks it is 11pm from the origin of journey time. Therefore you have to stay awake longer. The issue with flying west is that you wake up multiple times in the night and wake up early. When it is 3am in the morning, your body thinks it is already 10am and gets ready to wake up. When flying west you need to ‘delay’ your body clock.
The aim of these strategies is to produce a ‘phase shift’ which simply means advancing or delaying your circadian rhythm in order to promote rapid adaptation to your new time zone. Each of the strategies involves the application of a stimulus which under normal conditions sets the circadian rhythm. Just to get technical, these stimuli are called Zeitgebers (German for time givers). The most important stimulus for setting the circadian rhythm is light. Other weaker stimuli include food, exercise, sleep and pharmacological treatments. It is important to apply these at the correct time and dosage to ensure a shift in your rhythm in the right direction. ‘Forward for the east and backward for the west.’ You can use these as part of a pre-flight strategy to prepare for the new time zone as well as on arrival at the destination to adapt rapidly.
To Adapt or Not to Adapt: For short trips of one to two days, the general recommendation is not to adapt to the destination time zone. Since there are currently no instantaneous jet lag cures, any attempts to adapt would take longer than the actual trip length and would just make things worse. The consensus in this case is to stay on ‘home time’. Go to sleep, wake up, eat meals according to your home schedule. For events like meetings that occur at odd times, you can use simple strategies like short naps and mild stimulants like caffeine.
For trips longer than a day or two, it is best to try and adapt to the destination time in order to maintain your usual level of performance.
Light Therapy: Blue wavelength light has the biggest impact on the circadian rhythm. There are special receptors in the back of the eye which pick up light and send information directly to the part of the brain which acts as the master clock (suprachiasmatic nuclei or SCN). One of the functions of the master clock is to regulate the release of a hormone called melatonin. The presence of light results in a reduction in melatonin production. Decreased melatonin equals decreased sleepiness.
So how do we know that the SCN is the master clock? Experiments have been conducted where this part of the brain has been surgically removed in rats. The result? They lose all circadian rhythm and become active at random times.
But it gets more interesting. Until recently it was thought that the SCN was the only part of the body responsible for maintaining circadian rhythm. It is now known that individual organs and even individual cells all have their own rhythms and the SCN keeps them all in sync. This is one possible reason why different symptoms of jet lag take varying times to recover. The fastest to adjust is sleep rhythm followed by the temperature rhythm, gastrointestinal and then most hormonal rhythms.
So what is light therapy? It is a simple intervention which involves exposure to light at specific times to create a phase shift (advancing or delaying) in the circadian rhythm. This means you get exposure to light at different times depending on how you want to adjust your body clock. This is a popular and accepted therapy used frequently by athletes travelling for competition because rapid adjustment to a new schedule is paramount to their success. For example if the LA Dodgers are travelling to Australia, they use a jet cabin fitted with LED light bulbs. They also sent someone ahead to Australia to fit their hotel rooms with the same bulbs to continue their therapy.
Sleep glasses are an interesting commercial product. These glasses when worn shine blue light into your eyes. Wearing them according to the times required can create phase shifts in the desired direction.
The basics: If you want to delay your circadian rhythm i.e. go forwards in time you should be exposed to light just before bedtime. This will gradually shift your body clock back by a fraction every day. You should also avoid light in the mornings when you wake up. A solution to this can be sunglasses.
If you want advance your circadian rhythm you should be exposed to light in the early morning. You should avoid light during a crossover point where you might induce an advance or delay when you intend the opposite which occurs 2–3 hours before waking.
One last hack: 1mg of Vitamin B12 taken daily has been shown to increase the effects of bright light. This boost in response to light helps to turn off the melatonin signalling in your brain helping the transition from sleep to alertness.
Chronobiotics (rhythm shifting drug), melatonin: Melatonin is the sleep hormone which is released by the pineal gland (small gland in the brain) about two hours before bedtime every day. It causes the veins to dilate and thus a fall in blood pressure and temperature which promotes sleep. This occurs naturally every night provided light conditions are dim as melatonin production is inhibited by light.
Melatonin can be pharmacologically manufactured and can be purchased as a drug to assist in the time zone adaptation. Just like light therapy, timing and dosage is important here. Dosing at different times can result in a phase advance or a phase delay. To advance your rhythm, take it before bed time. To delay your rhythm take it towards the end of your sleep cycle. There is little evidence for delaying rhythms but good evidence for advancing them.
The American Academy of Sleep Medicine recommends melatonin use to promote adaptation. The recommended dose is 2–5mg for upto 4 days after travel. Obviously, do consult your own doctor before giving this a try. As melatonin is quite effective and has a broad application, drug companies are developing new formulations including Rozeram and Valdoxan. But there are limited clinical trials on these drugs and enough is not known to recommend them at this stage. If you are an athlete, be aware that the legal status of melatonin varies in different countries and also within the World Anti -Doping Agency.
Exercise: There is conflicting evidence regarding exercise and jet lag. However the current consensus is that 1–3 hours of exercise can induce circadian phase shifts. Early morning exercise is associated with phase delays in the circadian clock and early evening exercise is associated with phase advances.
Diet and meals: Circadian rhythms in the gastrointestinal system and the liver regulate the timing of gut motility, absorption of food and blood nutrient concentrations which are all critical for optimum performance. These rhythms are primarily controlled by eating and secondarily affected by light. There is some evidence to suggest eating meals at set times can enhance jet lag adaptation but this is far from conclusive. The National Sleep Foundation of America states that contrary to popular belief, different types of food have no effect on minimizing jet lag. At this point, I would say that exact meal planning for jet lag is impractical as the inconvenience will outweigh the benefit for most.
Pre-adaptation: All of the above methods can be used pre-travel to adapt to the new time zone before arrival. It is always better to gradually, rather than abruptly shift your body clock. The problem is that this requires some planning and could isolate you from the home and social schedule a few days before departure. Some interesting studies in astronauts have shown a pre-adaptation shift of a total of 9 hours was possible. But we are not all astronauts. The optimal adjustment is about 1–2 hours per day pre-travel.
· Don’t get drunk on the plane. Alcohol induces drowsiness and can help with falling asleep but the quality of sleep is poor.
· Sleep on the plane only if it suits your destination time.
· For short trips of 2–3 days, stay on home time.
· Control your sleep environment — take ear plugs, eye masks, pillows, whatever you need to get uninterrupted sleep at the right time.
· Set your watch on the plane to destination time and start your routine in that time zone early on.
· Some people use stimulants and sedatives based on their destination schedule. Consult your own doctor about this.
· Exercise to promote wakefulness and get into the rhythm of your destination.