A few years ago, I flew from Helsinki to Reykjavik, and, thanks to the two-hour time difference, the first day of the trip felt interminable and I just wanted to go to bed early. True jet lag usually occurs when a person crosses several time zones within a short time.
The time difference is felt more strongly when one is flying from west to east than east to west because it is easier for us to lengthen than shorten our circadian rhythm. Most people are able to force themselves to stay awake occasionally, but very few are able to go to sleep when wide awake.
Conflict of rhythms
The human internal clock resides in the brain; groups of approximately 10,000 time-measuring cells are situated above the optic chiasm. These 'clock cells' receive the data on day and night's alternation from the eye's retina. In addition to the sleep–wake cycle, our internal clock controls other bodily processes, such as regulation of temperature and blood pressure.
Time your exposure to light correctly: jetlagrooster.com has tips for overcoming jet lag.
In jet lag, our sleep–wake cycle comes into conflict with the other rhythms of the body because it ends up out of pace with the body's internal temperature rhythm and hormonal rhythms, which are able to change by only about 1–2 hours within any 24-hour period.
Accordingly, the bigger the time difference between the point of departure and your destination, the longer it takes to get used to it. The adjustment time needed can be estimated by multiplying the number of time zones by 2 or 3 when flying westward or by 1.5 or 2 when flying east, depending on your personal ability to adjust.
Separated from time and location
In popular culture, jet lag is often depicted as if a state of mind, more a psychological experience than a physical one. In the Danièle Thompson film Jet Lag (Décalage Horaire, 2002), starring Juliette Binoche and Jean Reno, the very different – and, at first, vehemently disagreeing – central characters end up sharing a hotel room at Charles de Gaulle airport because all connecting flights have been cancelled on account of a strike and bad weather. The name of the film seems to refer to the confusion created in their minds by the turns of events they experience.
Likewise, in Sofia Coppola's Lost in Translation (2003), jet lag is connected to the sense of being an outsider that the characters experience in an unfamiliar culture. Their culture shock in Tokyo – paralleled in their life in general – is alleviated only by finding a kindred soul. These characters, Charlotte (Scarlett Johansson) and Bob (Bill Murray), can be described as two Americans who are lonely together in Tokyo.
One of the principal figures in the film, Tokyo itself, had left an indelible mark on Coppola in her earlier trips to the city. Likewise jet lag:
I remember having these weeks there that were sort of enchanting and weird. Tokyo is so disorienting, and there's a loneliness and isolation. Everything is so crazy, and the jet lag is torture.
Out, up, and on the move
You can start adjusting your internal clock a few days before you travel, but, at the very latest, try to start shifting your sleep–wake cycle backward or forward (depending on whether you are heading west or east) on the flight.
It is good to drink plenty of non-alcoholic drinks on the flight, especially water, and try to eat and sleep consistently with the destination time zone.
When you get there, exercise can help you recover from the effects of the time difference. In particular, a morning jog or walk can get your mind and body into the local time efficiently. By the same token, try to avoid vigorous physical exertion for a few hours before going to bed, because of its energising effect.
Rest before you fly
In addition to special-purpose airline lounges, Helsinki Airport provides rest areas that are open to all passengers. Sources of further information: www.finavia.fi/airports, www.helsinki-vantaa.fi/other-services
Text: Terhi Kivikoski-Hannula
Photos: Matti Rajala