What's the time Mr Sky ?

© David Gennard, The University of Manchester

Blue sky in the morning, the mice are sleeping, blue sky at night, the mice ignite

Our body is influenced by a great many things in our environment, and, as strange as it may seem, one of them is colour. Scientists at the University of Manchester have indeed discovered that the colour of light has an impact on how our body clock measures the time of day.

How did they go about proving it ? With mice of course ! They started out by noticing that light is bluer during twilight than during the day. They then exposed mice to various changes in lighting and recorded their electrical activity. Thanks to this experience, they found that cells were more sensitive to changes from blue to yellow than to changes in brightness. In the final phase, the scientists created an artificial sky, placed the mice underneath it for a few days, and measured their body temperature. When the sky became dark blue, just after nightfall, their body temperature reached its peak, which is normal for nocturnal animals. But when only the brightness of the sky was changed, the mice became more active before dusk. In other words, their body clock wasn't in sync with the day night cycle.

Dr Timothy Brown from the Faculty of Life Sciences led the research: " What's exciting about our research is that the same findings can be applied to humans. So in theory colour could be used to manipulate our clock, which could be useful for shift workers or travelers wanting to minimise jet lag. "


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