BERKELEY, Calif., Nov. 16 (UPI) -- Jet lag might make you more than just groggy and dazed, U.S. researchers say -- it might even make you stupid.
Researchers at the University of California, Berkeley, said hamsters suffering extreme, chronic jet lag had about half the normal rate of new neuron birth in one part of the brain and showed deficits in learning and memory, ScienceNews.org reported Tuesday.
The scientists subjected hamsters to simulated jet lag by advancing their day and night schedule by 6 hours every three days for nearly a month, "like a flight from New York to Paris every three days," study coauthor Erin Gibson said.
Jet lag decreases the numbers of new neurons being created in the hippocampus by about 50 percent, the team found, as mental function suffered.
Even after 28 days of a back-to-normal schedule, the formerly jet-lagged hamsters still showed learning and memory problems, Gibson said.
The mismatch between the internal body clock and the external environment "is having a long-term effect on learning and memory," Gibson said.
While it's not certain exactly how these cognitive problems are induced by jet lag, the sleep hormone melatonin, stress and increased cell death are all possible culprits that need to be explored, she said.