Jet lag is a condition marked by fatigue and irritability as a result of airtravel across several time zones.
Living organisms are accustomed to periods of night and day alternating at set intervals. Most of the body's regulating hormones follow this cycle, knownas circadian rhythm. Body temperature, sleepiness, thyroid function, metabolic processes, and the sleep hormone melatonin all cycle with daylight.There is a direct connection between the retina (where light hits the back ofthe eye) and the part of the brain that controls all these hormones.
When people are without clocks in a compartment that is completely closed tosunlight, most of them fall into a circadian cycle of about 25 hours. Every morning the sunlight resets the cycle, stimulating the leading chemicals and thus compensating for the difference between the 24 hour day and the 25 hour innate rhythm.
Today, technology has surpassed adaptability, at least momentarily. In a single day, we can completely reverse the night-day rhythm by flying to the otherside of the earth. The chemicals are thrown into confusion. Most people reset their rhythms within a few days, demonstrating the adaptability of the human species; some, however, have trouble resetting their rhythms.
Traveling through a few time zones at a time is not as disruptive to circadian rhythms as traveling around the world, and people who travel west are lesslikely to experience jet lag than those who travel east.
The main symptom of jet lag is an altered sleep pattern--sleepiness during the day and trouble getting to sleep at night, together with indigestion and trouble concentrating. Individuals afflicted by jet lag will alternate in and out of a normal day-night cycle.
Exposure to bright morning sunlight in most cases will cure jet lag after a few days, although a few people will continue to have problems with sleep patterns.
Jet lag can be prevented in a number of ways. Eating a high-protein, low-calorie diet before taking off may help reduce the effects of jet lag. Drinking alot of water to prevent dehydration can prevent jet lag. Moving around as much as possible during an airline flight also helps by maintaining circulationand moving nutrients and waste through the body. Extra doses of vitamins A, C, and E, as well as zinc and selenium, two days before and two days after a flight help to ease jet lag. People who don't have enough melatonin may avoid jet lag by taking this hormone, although its use is controversial dueto concerns about its safety.
Jet lag usually lasts from 24-48 hours after air travel. In that short time period, the body adjusts to the time changes, and with enough rest, it returnsto normal circadian rhythm.