Extensive, long-haul travel can wreak havoc with your ability to function – even for the privileged few who trot round the globe in comfort.
In addition to the immediate impacts of jet lag: difficulties sleeping or staying awake; digestive issues; fatigue and irritability, Jamie M. Zeitzer, an associate professor at Stanford’s Center for Sleep Sciences and Medicine says there are also worrying longer-term consequences that depend on the frequency of your travel.
除了时差反应这种短期影响外（难以入睡或保持清醒；消化不良；疲倦易怒）斯坦福睡眠科学和医学中心（Stanford's Center for Sleep Sciences and Medicine）副教授杰米·齐特琴（Jamie M. Zeitzer）表示，还有一些令人担忧的长期后果，具体情况取决于你旅行的频率。
These can include greater susceptibility to infection and increased risk to longer-term conditions such as Alzheimer's and cancer. “Not to be alarmist, as the impacts are small, but they do appear cumulative and with a lifetime of ignoring adequate sleep, the risks of these diseases are definitely greater,” he says.
One study from University of California, Berkeley, confirmed that acute disruption of circadian rhythms (body clocks) caused memory and learning problems and even long-term changes in brain structure.
加州大学伯克利分校（University of California, Berkeley）的一项研究证实，生物周期节律（生物钟）受到严重破坏会引发记忆和学习问题，甚至长期改变大脑结构。
The neurological consequences of heavy travel can remain “long after travellers have returned to their regular schedule,” according to neuroscientist, Tara Swart. Swart is also a senior lecturer at Massachusetts Institute of Technology (MIT) and the first ‘neuroscientist in residence’ at London’s luxury Corinthia Hotel, where she has developed a programme to help clients overcome the mental and physical stress of heavy travel.
神经科学家特拉·斯瓦特（Tara Swart）表示，"当旅行者恢复正常生活很长一段时间之后"，高强度的旅行产生的神经后果仍会存在。斯瓦特还是麻省理工学院的高级讲师，也是伦敦豪华酒店科林西亚（Corinthia Hotel）的"驻店神经学家"，她在那里开发了一个项目，帮助客户克服繁重的旅程给身心带来的压力。
The good news is that experts say simply being aware of the impact and making small changes to your travel habits can help boost mental resilience – whether you’re a VIP or not.
Get in the zone
With jet lag, when there are abrupt, large shifts in external time, our internal timing system uses environmental cues, like the presence or absence of daylight, to resynchronize to the new time zone at an average rate of one hour per day, according to UC Berkeley psychology professor Lance J. Kriegsfeld. So, if travelling from New York to Paris, it will take five days on average to synchronize to Paris time. “For frequent, long-distance travellers, their circadian systems are still trying to catch up when they are preparing to fly to the next destination,” he says.
加州大学伯克利分校心理学教授兰斯·克里格斯菲尔德（Lance J. Kriegsfeld）表示，当外部时间突然发生剧烈变化时，就会出现时差反应，这时候，我们内部的计时系统就会利用周围环境中的线索（例如是否存在日光），以每天1小时的平均速度与新的时区重新同步。所以，如果从纽约到巴黎，平均需要5天才能适应巴黎的时间。"对于经常长途旅行的人来说，当他们准备飞往下一个目的地的时候，生物钟仍在努力追赶。"他说。
So, in order to stay one step ahead anticipate the change to your natural rhythms by “adjusting your body clock in advance,” Swart advises. Reset your watch at the beginning of your journey to the time zone of your destination. Depending on whether you’re flying east or west, you’ll want to try and expose yourself to additional light in the morning or evening a few days before flying. (Going east? Expose yourself to morning light. Going west? Expose yourself to light in the evening before you go.)
Skip the pretzels
Many travellers end up eating unhealthy meals when they are on the move, but it’s essential to eat properly. Choosing the right meals at the right time of day can help readjust your natural rhythms quicker. To reset your body’s rhythm, try fasting on the flight until breakfast in the new time zone.
Repeated jet lag can also contribute to obesity and other significant health problems, according to a study by immunologists at the Weizmann Institute of Science in Israel. Swart suggests taking probiotics before, during and after a big trip to counteract any disruptions to your gut’s natural bacteria.
以色列魏茨曼科学研究院（Weizmann Institute of Science）的免疫学家进行的一项研究发现，重复遭遇时差反应还会引发肥胖和其他健康问题。斯瓦特建议提前服用一些益生菌，以便在旅行途中和旅行结束后抵消肠胃中天然菌群受到的破坏。
Heavy travel doesn’t just have adverse physical effects; it can also interfere with your mental clarity. In the short term, disruption to a good night’s sleep has been shown to reduce your working IQ by as much as five to eight points the next day, says Swart. And that’s just in the short term.
When it happens repeatedly over time, neurotoxins are allowed to accumulate in the brain, which could lead to degenerative diseases such as Alzheimer’s and Parkinson’s in later life according to Swart. The glymphatic system (responsible for flushing out these toxins) needs seven to nine hours of good quality sleep each night to completely clean the brain, says Swart. “By disrupting our sleep through regular travel, we prevent the glymphatic system from performing this crucial function,” she says.
If you feel sleepy during daylight hours when you first arrive somewhere new, try and do some aerobic exercise. Even if you do not feel tired in the evening, try to sleep anyway. And avoid drinking a coffee when you hit that wall in the afternoon. Caffeine will only make the process much harder when it’s time for bed, says Swart.
Smartphone use before bed is the ultimate no no. The blue light emitted from it (or from other devices like it) can trick the pineal gland into thinking it’s daytime and therefore block the production of melatonin, which would normally help you sleep.
We are all jet lagged
But Kriegsfeld adds that heavy travellers are not alone. “We are all pretty much continuously jet lagged in the modern world, not just frequent travellers,” he says. “Except for those working outside, we all get too little sunlight during the day and too much light at night through artificial lighting and light-emitting devices. Likewise, most people change sleeping schedules on the weekend, for example, sleeping in. Together, this leads to relatively chronic jet lag in the modernised world.”