Cyclic Hotline
21st May 2001, 08:48
This is your stewardess speaking. Er, where are we going?
BY DAVID CHARTER, HEALTH CORRESPONDENT (Times)
AIR crew suffer from memory loss and disorientation because repeated jet lag shrinks the brain, scientists have found.
The discovery may also have implications for other people whose sleep patterns are disrupted regularly, such as shift workers and parents with young children. The shrinkage affects the brain’s right temporal lobe, which is involved in visual recognition and spatial memory.
Regular long-haul flying appears to increase the production of the stress hormone cortisol which may be responsible for the shrinkage, according to a research team from the University of Bristol medical school who scanned the brains of airline crew with five years’ flying experience. Crew members who had long intervals between long-haul trips did not seem to suffer.
The tests were conducted on female crew members, because women appeared to suffer more acute jet lag than men.
Evidence of impaired thinking ability in cabin crews had already emerged in a previous study by the team led by Kwangwook Cho. For the new study, they used magnetic resonance imaging to measure the brain volumes of 20 women, aged 22 to 28, who had five-year careers with international airlines and flew across at least seven time zones.
The study measured short-term memory and cognition, both functions of the right temporal lobe, and found significant deficits. Cognition tests involved understanding and differentiating between simple symbols, such as the design of the American and British flags. To measure memory, the women were asked to recall the location of dots on a computer screen after 20 to 50-minute intervals.
Results published in the journal Nature Neuroscience concluded: “Salivary cortisol levels in cabin crew after repeated exposure to jet lag were significantly higher than after short distance flights, and the higher cortisol levels were associated with cognitive deficits.
“The present study demonstrates that significant prolonged cortisol elevations produced reduced temporal lobe volume and deficits in spatial learning and memory.”
Other research has shown that chronic high cortisol levels due to severe depression and post-traumatic stress is associated with temporal lobe shrinkage. Jet lag is a condition suffered by many people who travel over time zones characterized by fatigue, disorientation and disrupted sleep. Dr Cho said that he had left men out of the sample group because they appeared to suffer less acute jet lag.
It was not known how long the brain changes persisted, or whether they were reversible.Dr Cho added: “I found there was no deficit of language, but certain short-term objective memory and very simple abstract cognition was quite bad.”
BY DAVID CHARTER, HEALTH CORRESPONDENT (Times)
AIR crew suffer from memory loss and disorientation because repeated jet lag shrinks the brain, scientists have found.
The discovery may also have implications for other people whose sleep patterns are disrupted regularly, such as shift workers and parents with young children. The shrinkage affects the brain’s right temporal lobe, which is involved in visual recognition and spatial memory.
Regular long-haul flying appears to increase the production of the stress hormone cortisol which may be responsible for the shrinkage, according to a research team from the University of Bristol medical school who scanned the brains of airline crew with five years’ flying experience. Crew members who had long intervals between long-haul trips did not seem to suffer.
The tests were conducted on female crew members, because women appeared to suffer more acute jet lag than men.
Evidence of impaired thinking ability in cabin crews had already emerged in a previous study by the team led by Kwangwook Cho. For the new study, they used magnetic resonance imaging to measure the brain volumes of 20 women, aged 22 to 28, who had five-year careers with international airlines and flew across at least seven time zones.
The study measured short-term memory and cognition, both functions of the right temporal lobe, and found significant deficits. Cognition tests involved understanding and differentiating between simple symbols, such as the design of the American and British flags. To measure memory, the women were asked to recall the location of dots on a computer screen after 20 to 50-minute intervals.
Results published in the journal Nature Neuroscience concluded: “Salivary cortisol levels in cabin crew after repeated exposure to jet lag were significantly higher than after short distance flights, and the higher cortisol levels were associated with cognitive deficits.
“The present study demonstrates that significant prolonged cortisol elevations produced reduced temporal lobe volume and deficits in spatial learning and memory.”
Other research has shown that chronic high cortisol levels due to severe depression and post-traumatic stress is associated with temporal lobe shrinkage. Jet lag is a condition suffered by many people who travel over time zones characterized by fatigue, disorientation and disrupted sleep. Dr Cho said that he had left men out of the sample group because they appeared to suffer less acute jet lag.
It was not known how long the brain changes persisted, or whether they were reversible.Dr Cho added: “I found there was no deficit of language, but certain short-term objective memory and very simple abstract cognition was quite bad.”