Psychologists working at the University of Berkeley have found that jet lag affects the brainís ability to retain facts long after returning to a more regular schedule.
The researchers came to this conclusion after they had subjected a group of female Syrian hamsters to six-hour shifts in their circadian rhythms - which is the same as flying London to New York. They applied quite a tough regime to these hamsters, exposing them to this artificial jet lag twice a week for four weeks.
They also kept a control group of hamsters whose schedules remained unchanged. Lance Kriegsfield and his colleagues then put both sets of hamsters through tests which measured their ability to learn and remember simple tasks, such as locating hidden food.
As expected, the jet-lagged hamsters didnít perform as well as the control group. But what was surprising is that the jet-lagged ones continued to perform poorly even a month after their rhythms returned to normal.
They also found that the jet-lagged hamsters only had half the usual number of new neurons in the hippocampus area of the brain, which is crucial for memory and learning.