These days, air travel, often over several times zones, is commonplace. Unfortunately, our bodies are no more immune to the effects of “jet lag” than those of our primitive ancestors, for whom rapid air travel was not an option!
“Jet lag” is the term used to describe the physical and mental distress experienced when the body's internal clock, or circadian rhythm, becomes desynchronized with the external time zone. Symptoms of jet lag include insomnia, sleepiness, impaired performance, diminished alertness, irritability, depression and worsening of migraine.
According to a study conducted at a mental health center at Hebrew University of Jerusalem, jet lag may even trigger more serious conditions. These researchers investigated the relationship between jet lag and major psychiatric disorders. The study involved 152 patients who had been hospitalized for psychiatric disorders within a six-year period (but who were mentally healthy at the time of travel or who had been free of any psychiatric symptoms for at least one year before travel). They assigned patients to one of two groups, based on the number of time zones they had crossed while traveling to Israel. The team documented a significant correlation between crossing seven or more time zones and a relapse of psychiatric disorders.
There is also evidence that chronic disruptions of the circadian rhythm could speed cancer growth. A study conducted in 2004 in France ((Filipski E et al) looked at this possibility. Working with mice, they entrained one group to a normal rhythm of 12 hours' daylight followed by 12 hours of dark. A second group of rodents repeatedly underwent 8-hour advances of the light-dark cycle every two days. Both groups were injected with cancerous cells known to cause tumors in mice. Compared with the mice kept on a normal sleep-wake cycle, the jet-lagged mice experienced faster tumor growth.
While traveling, do you try to keep a normal sleep pattern?