A study that has well-traveled older business-mice trembling: Aged mice whose circadian rhythms were messed with in a manner similar to what happens when you're jet-lagged on a westward trip had higher death rates than their eastern-directed and nontraveling fellow mice. From The Economist:
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 â€westboundâ€ groupâ€”those whose light cycle was repeatedly delayedâ€”32% died. The death rate in the â€eastboundâ€ group, whose light cycle was brought forward, was 53%. The results are published in this week's issue of Current Biology.
What does this mean to you? Probably not much, unless you have a habit of carrying your elderly pet mouse on business trips. But I thought it was interesting.