Urban living may alter your biological clock
Living in the city can have a major effect on the internal clocks of both humans and animals which could lead to increased incidence of health problems and reduced lifespan, researchers have claimed.
Biologists from the University of Glasgow in UK and the Max Planck Institute for Ornithology in Germany have now discovered for the first time that the biological rhythms of city-dwelling organisms are changing in response to city living.
The researchers measured the circadian rhythms, the 24-hour cycle of biological activity, of groups of urban and rural blackbirds in southern Germany and found that the city-dwellers had faster and less robust internal clocks than rural blackbirds.
In the wild, city birds woke up earlier and rested less than forest birds. The researchers captured adult male European blackbirds from the city of Munich and a nearby rural forest. Each bird was equipped with a lightweight radio-transmitter which monitored their daily levels of activity in the wild for 10 days before they were recaptured.
They were then kept in light-proofed, sound-insulated chambers and their circadian rhythms were measured under constant conditions, without any environmental information that could serve as a “clock”.
In this way, each bird’s own, internal rhythm could be tested. Once the tests were complete the birds were returned to the wild.
“The daily cycles of activity and rest are based on biological rhythms which have evolved as an adaptation to the rising and setting of the Sun,” said Barbara Helm, of the University of Glasgow’.
“Our tests were designed to benchmark the internal rhythms of the birds under controlled conditions and to determine a link to the birds’ chronotype in the wild.
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