It's hard to say with certainty who coined the term, but according to a quick newspaper database search, "jet lag" was first used in a Los Angeles Times article on February 13, 1966. "If you're going to be a member of the Jet Set and fly off to Katmandu for coffee with King Mahendra," wrote Horace Sutton, "you can count on contracting Jet Lag, a debility not unakin to a hangover. Jet Lag derives from the simple fact that jets travel so fast they leave your body rhythms behind."
The reporter continued, "The Federal Aviation Agency has been so worried about the effect on pilots, not to mention diplomats and businessmen, that they have conducted a heavy study under the catchy title, ‘Intercontinental Bio-Medical Flight Project.' "
By the time of Sutton's article, jet passenger service was already 14 years old. But it wasn't until December 1965 that the FAA got around to analyzing its effects on human circadian rhythms. The studies were based on assessments of subjects aboard a series of intercontinental flights crossing multiple time zones from east to west, west to east, and north to south. While all test subjects felt fatigue, those traveling east to west experienced significant impairment of "psychological performance," which didn't occur on other flights. (It's unclear why this first experiment concluded that westward travel was more taxing than eastbound flights, when subsequent studies found just the opposite. Perhaps the number of test subjects was too small—a mere four FAA employees.)
By April 1966, concerns about jet lag had even spread to major league baseball teams. A spokesman for the Chicago White Sox told the New York Times that "half a dozen players on every team are affected by air travel." According to the article, "It takes eight days for the body juices to return to normal after a long jet flight…. Plain fear [of flying] plus the Jet Lag can make a recently debarked team too logy for at least the first game of any given series." It must have been scant comfort to hear the FAA's advice for offsetting the syndrome: sleeping, avoiding alcohol, and eating lightly.
In 1980, NASA (in collaboration with the FAA, and at the request of Congress) established a program to further study the problem. The NASA Ames Fatigue/Jet Lag Program set out "to collect systematic, scientific information on fatigue, sleep, circadian rhythms, and performance in flight operations." Researchers determined that if the average biological clock were allowed to run at its natural rhythm, "the average internal biological clock would actually have a cycle slightly longer than our 24 hr. day, about 25 hr…. Therefore, when traveling westward, the circadian day is lengthened (or delayed) and promotes adjustment to the new time zone. Conversely, when flying eastward, the circadian day is shortened (or advanced), contrary to the natural tendencies of the internal clock."
Based on data from more than 500 pilots, the study recommended "cockpit sleep opportunities," similar to the rest periods mandated by the U.S. Air Force and some international carriers to combat pilot fatigue, but noted "controlled rest is only one acute inflight countermeasure and is not the panacea for all of the sleep loss and circadian disruption engendered by long-haul flight operations."
While there's still no cure for jet lag, searching for one is big business. A 2006 study co-authored by biologist Gene Block of the University of Virginia and reported on healthcentral.com came to the depressing conclusion that elderly mice exposed to time shifts that replicate the effects of jet lag die earlier. But last year, Diego Golombek at Quilmes National University in Buenos Aires released a study indicating that in hamsters traveling east, jet lag was reduced by small doses of Viagra. ("It's true that some people will be worried about the—let's call them side effects," Golombek was quoted as saying.) And in May 2008, the journal Science reported that Clifford Saper of Harvard Medical School discovered that fasting for 16 hours before a long-distance flight enabled subjects to better resist jet lag.
Until there's a cure, perhaps weary travelers should embrace author Pico Iyer's outlook: "Because jet lag is so much a part of my life now, I tell myself I will make the most of it; attend to it, enjoy its disruptions, as I would those of a geographically foreign place."