Jet Lag Information
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What Causes Jet Lag?
Most people who travel long distances complain of jetlag the fatigue, indigestion, sleeping problems and general malaise that disrupt the first few days in a new time zone. Jetlag makes business travellers less productive and more prone to making mistakes, and keeps holidaymakers from enjoying their time off.
Jetlag is actually caused by disruption of your "biological clock" a small cluster of brain cells that controls the timing of biological functions (or circadian rhythms), including when you eat and sleep. The body clock is designed for a regular rhythm of daylight and darkness, so that it is thrown out of "sync" when it experiences daylight and darkness at the "wrong" times in a new time zone. The symptoms of jetlag often persist for days while the internal clock slowly adjusts to the new time zone.
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How Can it be Prevented? |
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| Now a new anti jetlag system is available that is based on proven extensive pioneering scientific research in the field of circadian physiology. Dr Martin Moore Ede, Professor of Harvard Medical School and one of the leading scientists in the field, helped Bio-Brite develop a practical strategy to adjust the body clock to the new time zone much sooner through controlled exposure to bright light. The time zone shift is easy to accomplish and eliminates most of the discomfort of jetlag. |
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| A successful time zone shift depends on knowing the exact times to either seek and avoid bright light. Exposure to light at the wrong time can actually make jetlag worse. The proper schedule for light exposure depends a great deal on specific travel plans. Taking a night flight to Tokyo for instance creates very different demands than a day flight to Los Angeles. Personal variables are important too; a "night owl" person typically needs a different schedule to a "lark." |
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| Data on a specific flight itinerary and the individual's sleep pattern are used to produce a customised Jet Lag Trip Guide with instructions on exactly when to seek bright light and when to avoid it. When the Trip Guide calls for bright light you should spend time outdoors if possible (normal indoor lighting is not bright enough to reset the biological clock). If it is dark out, or the weather is bad, or you are on an aeroplane you can use the Jet Lag Light Visor™ to provide the necessary light stimulus. The patented Visor is a comfortable, lightweight head piece that looks something like a tennis visor. The Visor is powered by standard AA batteries and is fully portable, allowing a range of activities such as reading, watching TV or working. |
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Background Science |
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| How does it work? The essential scientific discovery is that our body clocks can be shifted by exposure to bright light and darkness in sequence but only when the exposures are immediately before and after the "reset point", in the middle of the night (as defined by the time zone we started from). Essentially bright light acts as a stick and dark as a carrot, and the reset point is pushed by light and pulled by darkness to a new time. It's just like turning the hands on your biological clock as well as on your watch. |
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More About Jet Lag Research |
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| We now know that the human species evolved special systems to synchronize the biological clock with the timing of dawn and dusk. Special cells in the retina at the back of the eye detect the brightness of light (number of photons) falling on the eyes and route the information back to the biological clock. This is done through a non-vision tract, the Retinohypothalamic Tract (RHT), a special bundle of nerves from the retina to a small cluster of nerve cells called superchiasmatic nucleus (SCN), commonly referred to as the biological clock. |
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| The biological clock behaves very differently in response to light signals depending on the time of day or night. During most of the day, the clock virtually ignores light signals, but come evening, light signals (if sufficiently bright) act to delay the timing of the clock (sending it westbound). The distance shifted depends on the timing and intensity of the light. Progressively later still, up until about 4:00 a.m. (presuming a normal sleep-wake schedule), the shift gets bigger and bigger the later the light is delivered. Past the critical transition point in the middle of the night, just about 2 hours before normal wake-up time, the shifts suddenly change from big delays to big advances (eastbound shifts). Progressively later still, the advance shifts are reduced in size until, an hour or two past dawn, the clock is no longer responsive to light. |
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| This so-called phase-response curve to light is fundamental to understanding how biological clocks synchronize to their environment. Fly westward and the delayed sunset means that light falls on a phase of the SCN clock that shifts it westbound. Fly eastward and early morning light from the earlier dawn advances the biological clock. |
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| Melatonin, a natural hormone that is critical to the regulation of sleep and circadian rhythms, has been administered experimentally to humans to test its efficacy for inducing sleep. Results are promising for preventing jet lag, particularly if used in combination with light therapy. It now appears that it will be several years before melatonin will be marketed for this application. Melatonin, currently available in some health food stores, has often been irresponsibly promoted for preventing jet lag. However, since its production is not regulated, purity is questionable and its consumption could lead to serious side effects. |
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| For some reason, airlines always schedule their flights form the U.S. East Coast eastbound to Europe to take place overnight. A flight eastbound from Los Angeles to Boston is only slightly less distance, yet on that trip all but the most cost-conscious or most harried red-eye travelers fly using the day. In contrast, when flying eastbound to Europe, travelers leave early in the evening and often arrive at 5:00 or 6:00 a.m., which is midnight to 1:00 a.m. East Cost U.S.A. time. Therein lies the problem. |
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| Walk outside in the bright sunlight when you get off the plane in, say, Madrid, and your biological clock gets a healthy dose of light - but it is before 4:00 a.m. East Cost body clock time. The light signal therefore hits your biological clock at the phase when westward, not eastward, resetting occurs. This jolt of light will therefore send your body clock merrily on its way toward Hawaii time, just when you need to adjust to the schedule in Madrid. This is scarcely a help to your jet lag! If, however, you wait until 9:00 or 10:00 a.m. local time before exposure to bright outdoor light, the light will boost your biological clock eastward and help you with your adjustment to life in the new time zone. |
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| Experienced travelers may have observed that traveling east is usually more taxing than westward trips. This anomaly is also based on the characteristics of the biological clock. Human circadian rhythms normally run on an approximately 25 hour day. If your clock was not reset by environmental light patterns, you would find yourself waking up an hour later each day. This tendency to extend the day length is like flying west one hour each day. So when you do fly west, it is easier to adjust than it is when you fight the clock's natural drift by flying east. |
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| The Jet Lag Calculator uses strategies such as these to shift your body clock appropriate to your normal body clock rhythm and a particular itinerary. From your normal wake up time, a good approximation of your critical transition point can be made. Based on extensive research, the Jet Lag Calculator uses the direction of travel and the number of time zones traveled to calculate the light dose scheduling to "hit" the phase response curve at the times which will shift it in the right direction. |
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You can learn more about circadian rhythms and light therapy at: Biobrite.com or the Circadian Learning Center. |
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