How should we adjust to the time difference when flying from one time zone to another? For the inhabitants of our country, this is an actual problem, because Russia, stretching from east to west, is located in nine time zones. There are quite a few people who, for various reasons, must travel long distances in our country and abroad. Travelers need to be able to quickly adapt to new conditions, maintain clarity of mind and work efficiency during the day, and normal sleep at night.
It is known that a trip through several time zones affects the circadian sleep-wake rhythm, causing insomnia or drowsiness. This happens because, being already in the new time zone, the human body still lives in its usual mode: waking up, feeling hungry and falling asleep in the old time zone. The adjustment will take several days or weeks depending on how many time zones are overcome.However, the internal clock can be translated faster if you use the influence of the most powerful regulator of the daily rhythm – a bright light. If you are in a lit room or without sunglasses on a bright day, the effect of light on the eyes is enhanced. You can influence them with darkness if you darken the room for a certain time or wear very dark glasses during the day. By influencing, in this way, your biorhythm with light or darkness, you can quickly translate the internal clock and adapt to new conditions in 1-3 days, restoring sleep and working capacity.
I remember my personal feelings during the first few days after the flight to Cuba from Moscow. At first, work in the Havana hospital was given with great difficulty due to the time difference. At night there was an amazing vigor, I didn’t want to sleep at all, and my head worked clearly. It seemed that you can do a lot of things right now, at night. But such activity turned into daytime sleepiness and a feeling of irresistible fatigue. This was further aggravated by the immense impressions of the tropical nature of the island, the bright colors of unprecedented colors and the unusually hot, moist sea air. The first 10 days worked hard. But the responsibility to colleagues and patients, as well as the density of the scientific program, forced to mobilize themselves by an effort of will. It is a pity that at that time I was not familiar with insomnia treatment methods,caused by desynchronization during long-haul flights. Then these aspects have not yet been finalized to practical recommendations. It is clear that it is much more difficult to transfer 10 days of adaptation than 2–3 days on the background of treatment with light and darkness.
How to calculate the time of additional exposure to darkness or light? For this purpose, a table has been developed or otherwise a calculator of the effect of light on the eyes for people moving to different time zones. A calculator (see table) shows when and at what time light should be avoided, and, conversely, expose oneself to its effects.
The calculator indicates the local time when you need to start a daylight exposure scheme on the first day of your stay.
For example, when flying to the east, when it intersects from one to ten time zones, you should avoid light exposure from the hour of local time specified in the calculator. To do this, you need to sleep or be in a darkened room or wear dark sunglasses on the street. After completing this recommendation on the first day, on the second – you need to start avoiding sunlight already 2 hours earlier than the day before, adding this time to that specified in the calculator. Each subsequent day begins another 2 hours earlier than the previous one, until full adaptation to local time occurs, and sleep disorders disappear.
When traveling westward by more than eleven – twelve time zones, the calculator will show the time when light began to be exposed on the first day. It is necessary to avoid sunlight after the specified time. Then every next day the scheme of actions starts 2 hours later, until the organism becomes fully accustomed and sleep is restored.