Is there any medical or scientific evidence for the practice of preventing jet lag after long plane rides by placing a lighted flashlight behind one’s knees just prior to landing? I read a short piece in an airline magazine a few years ago and finally got around to trying it on two long plane trips–to and from the eastern Mediterranean and to and from New Zealand. It worked. I had no jet lag and fell into normal wake/sleep cycles in those time zones. But friends say I experienced a psychological placebo. –Gene Wojciechowski, Richmond, New Hampshire
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First let’s get the facts straight. Nobody except a few screwballs claims that merely sticking a flashlight behind your knee will prevent jet lag. It makes a good yarn, though, which explains how one Les Adams (no relation) managed to get himself quoted in jet lag stories by the Wall Street Journal and ABC’s 20/20. All you had to do, Adams said, was strap a Maglite to your leg and let it shine into the crease behind your knee for an unspecified time. He planned to market a “Jet Lag Lite” for those who couldn’t master the art of flashlight strapping on their own.
Campbell and Murphy had put 15 volunteers in a lab for four days and at varying times during the second day had hooked them up to a knee light (not a flashlight but a fiber-optic pad illuminated by a halogen lamp) for three hours. Meanwhile the researchers monitored the volunteers’ body temperature and other indicators to determine the effect on circadian rhythms. Sure enough, they found that if the light pulse was administered before body temperature bottomed out (this typically occurs around 4 or 5 AM), the body rhythm was retarded three hours–that is, the temp hit bottom at 7 AM rather than 4 and was still doing so a couple days later. If the light pulse was administered after the low point, the rhythm was advanced a couple hours.
Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.
