London’s dawn sky was orange when I boarded the flight. When I got off some six hours later in Montreal, Canada, it was still orange.
My body didn’t like it one bit. All of us operate based on the circadian rhythm, where light determines whether it’s time to be active or have a snooze. Those constantly darting across multiple time zones are familiar with that sinking feeling when the body clock gets completely mixed up and won’t adjust to the quick change in the light-dark cycle. The result, of course, is jet lag, caused by the disruption to the circadian rhythm – and for many of us, it’s a zombie-like state that results in moodiness, irritability, and deep fatigue. “Our internal clocks are not set to 24 hours. Unfortunately, exposure to light at the wrong time of day will cause your social sleep schedule to desynchronise from your internal clock,” says Erin E Flynn-Evans, a member of Nasa’s fatigue countermeasures group.
我的身体一点都不喜欢这种状态。所有人都有一套自己的生理节律，由光线来决定究竟是该精神百倍还是昏昏欲睡。经常穿梭于不同时区的人对生物钟彻底紊乱后的这种消沉感受肯定不会陌生，每每此时，总是很难适应明暗周期的快速变化。结果便造成了时差反应，这是因为生理节律被打乱而产生的一种现象——对多数人而言，最直观的感受就是整个人像僵尸一样无精打采、昏昏欲睡、情绪不佳，并且容易烦躁。“我们的生物钟并不是按照24小时设置的。不幸的是，在错误的时间暴露在光线中会导致你的社会睡眠时刻表与生物钟脱节。”美国国家航空航天局(NASA)疲劳对策小组成员艾琳·E·弗林-伊万斯(Erin E Flynn-Evans)说。
It’s the aircraft’s speed that’s to blame; the time zone changes are just too rapid.
But some people experience these massive body shocks day in and day out: professional aircrew like pilots and flight attendants. So how do they cope with jet lag – or are they simply immune to it?
“Pilots suffer just like the rest of us, but they are typically provided with education sessions on how to manage their rest opportunities,” says Flynn-Evans. Most airlines have fatigue risk management programs to help pilots cope with jet lag – and pilots are even allowed to call in ‘fatigued’ when they feel like they are too jet-lagged to carry out their jobs safely.
The training prepares pilots to find out what works best for them – and stick to the routine. “When I started to fly long-haul, and asked older captains for advice on beating jet lag, they nearly all said ‘oh, what I think doesn’t matter – you’ll find out what works best for you.’ And they were right,” says Mark Vanhoenacker, a British Airways pilot and author of Sunday Times bestseller Skyfaring: A Journey with a Pilot.
这种培训可以帮助飞行员找到最适合自己的方法——并通过持之以恒的训练将其变成例行公事。“刚刚开始长途飞行时，我向资历较老的机长请教如何应对时差效应的方法，他们几乎异口同声地说，‘我认为这不重要——你得找到对你最有效的方法。’”英国航空驾驶员、《星期日泰晤士报》畅销书《翱翔天际：与飞行员一起旅行》(Skyfaring: A Journey with a Pilot)的作者马克·万霍耐克(Mark Vanhoenacker)说。
Flynn-Evans advises astronauts on how to beat jet lag – and the advice applies to regular travellers, too. First, always think about your direction of travel, as it will determine the times you should take a nap and times that you could consider taking supplements such as synthetic melatonin. Melatonin is a hormone that helps to set the body's sleep cycle; artificial melatonin is a popular alternative to sleeping pills (although the debate whether it really is effective in beating jet lag is yet to be resolved).
Most people find it easier to adjust to time changes when flying west rather than east. When neurologist Dr Lawrence D Recht studied 1991-1993 season records of 19 Major League Baseball teams, he found those that had to travel east usually surrendered one run more than usual in every game.
多数人发现，由东向西飞比由西向东飞更容易适应时区变化。当神经学家劳伦斯·雷希特(Lawrence D Reht)研究了1991-1993赛季19场美国职棒大联盟球队的比赛记录后，他发现当球队前往东部比赛时，往往会比常规状态下多失一分。
So if your flight is eastbound, it’s a good idea to start getting up early for several days before your trip and turn on bright lights, says Flynn-Evans. On the day of travel and on the flight, avoid light – wearing sunglasses can help – to advance your internal clock. And when you arrive at your destination, for the first few days sleep with your curtains open and allow in plenty of light.
However, if you are travelling west and chasing the Sun, stay up late before the journey and expose yourself to bright light in the evening, delaying the body clock. No need for sunglasses on the flight – try to get as much light as possible. “These light effects happen relative to your internal clock, so if you are traveling from Los Angeles to New York, you should keep your watch set to LA time and make sure that you are exposed to bright light in the NY morning, but not before 3am LA time. It’s tricky, because you have to make adjustments based on the time zone that you left, not the time zone where you are arriving.”
Long-haul pilot and flight safety specialist at Balpa (the British Airline Pilots Association) Stephen Landells recommends drinking plenty of water on the plane, eating lightly but at sensible times and trying to avoid caffeine or other stimulants.
Once at the destination, Vanhoenacker says that for him, “an 11am rule” works best. “If I can get to my hotel room or my bed at home by 11am, then I’ll have a nap for an hour or even two. Anything later and I’ll stay up until a normal bedtime. Whether or not I sleep on arrival, though, if I find myself struggling by late afternoon, a shorter nap can help – and 20 minute ones work a treat. Definitely set an alarm.”
Exercise is good, too, he adds – it refreshes you and makes you sleep better when you do eventually get your head onto the pillow. And he tries to find someplace green on his first day, even if it’s just a neighbourhood park. “And I’ve convinced myself it helps even to walk a little more – for that reason I usually avoid the moving walkways at airports, especially after a flight.”
Coffee and exercise
Not all pilots follow his routine, though. Some pilots prefer staying on their home time zone the entire time they’re away – but such an approach probably does not work for most business travellers, for whom it’s important to synch themselves with the rhythm of wherever they’re staying.
Betty Thesky is a flight attendant and author of Betty in the Sky With a Suitcase. She flies round trip to Europe from the US at least once a week. Unlike pilots, she says that she and other members of the aircrew don’t get any special training to fight jet lag – so she simply developed her own ways of dealing with it. “I arrive in Europe in the morning and allow myself to nap for a few hours, then force myself to get up even though my body wants to keep sleeping,” she says.
贝蒂·瑟斯基(Betty Thesky)是一名空乘人员，她还写过一本名为《带着旅行箱上天的贝蒂》(Betty in the Sky With a Suitcase)的书。瑟斯基至少每周都会从美国飞一次欧洲。与飞行员不同，她表示，她和其他机组成员没有接受任何应对时差效应的专门培训——所以，她研究了自己的一套方法来应对这一问题。“我早晨到达欧洲后，会睡上几个小时。随后，即便还想继续睡觉，我也会强迫自己起床。”她说。
To wake up, she drinks some coffee for a little kick, followed by upbeat music and exercise in her hotel room. “You would be surprised how some jumping jacks, sit ups, push ups and hand stands with the Bee Gee's Staying Alive in the background perk you up; then I'm ready to hit the streets.” And if you’re lucky to have a swimming pool at your destination, it really helps with stiffness, bloating and general fatigue associated with a long trip in a small seat, she adds.
为了保持清醒，她会喝些咖啡，然后听听欢快的音乐，并在酒店的房间里锻炼一会儿。“可以用Bee Gee乐队的《活着》(Staying Alive)做背景音乐，然后做做跳跃运动、仰卧起坐、俯卧撑和徒手倒立，这会带来意想不到的提神作用。之后，我就准备去逛街了。”如果你的目的地恰好还有游泳池，那绝对有助于缓解坐在狭小座位上长途旅行之后产生的各种疲倦和不适。
Experts at Nasa’s fatigue management team say that – on average – it takes travellers about a day per time zone to adapt. With tricks and practice, Vanhoenacker managed to reduce it to roughly two hours per time zone per day, so for a six-hour time change he’s back on track after about three days.
It does happen, though, that we know we need to sleep but just can’t. Vanhoenacker says that in that case, it’s nice to embrace the experience of getting to know cities at unusual times of the day. His favourite memories of Los Angeles involve waiting on a quiet beach for a cafe to open its doors for 5am breakfast; and when he thinks of Hong Kong, in his imagination it’s almost always late at night.