Evidence Suggests Jet Lag Can be Deadly (at Least in Mice)

The Economist reports that researchers at University of Virginia have tested how distorting circadian rhythms in mice can affect their health.

Each group contained nine young male mice and about 30 old male mice. The first group was placed on a normal daily cycle of 12 hours of light followed by 12 hours of darkness. The second had its 12 hours of light delayed by six hours once a week, replicating the jetlag experienced after travelling west. The third group had its 12 hours of light advanced by six hours once a week, mimicking eastbound travel. The experiment lasted for eight weeks.

As might be expected, the young mice in each of the three groups fared relatively well; just one died. Of the elderly rodents whose days and nights were unchanged, 17% died. But the number of deaths in the two groups whose day-and-night cycles had been tampered with was far higher. Among the “westbound” group—those whose light cycle was repeatedly delayed—32% died. The death rate in the “eastbound” group, whose light cycle was brought forward, was 53%. The results are published in this week’s issue of Current Biology.

Bottom line is that the elderly mice should consider flying westbound only…