The colours of a glorious sunset do more than inspire artists and poets − they could have a direct effect on the way our bodies function, research suggests.
Colour has a greater impact on circadian rhythm − the day/night clock system that regulates many biological processes − than light intensity, scientists have found.
In a series of experiments, researchers created an ‘artificial sky’ which reproduced daily changes in colour and brightness.
Mice exposed to the ‘sky’ for several days were found to be most sensitive to colour. The same result was obtained from other tests which showed that the body clocks of mice were more affected by changes in colour between blue and yellow than light levels.
Timothy Brown, from the Faculty of Life Sciences at the University of Manchester, said: “This is the first time that we’ve been able to test the theory that colour affects the body clock in mammals.
“It has always been very hard to separate the change in colour from the change in brightness, but using new experimental tools and a psychophysics approach we were successful.
“What’s exciting about our research is that the same findings can be applied to humans. So in theory, colour could be used to mani-pulate our clock, which could be useful for shift workers or travellers wanting to minimise jet lag.”
The scientists, whose findings appear in the online journal Public Library of Science Biology, began by looking at changes in light around dawn and dusk to see whether colour could be used to determine time of day.
The researchers then recorded body-clock electrical activity in mice shown different visual stimuli, and constructed the artificial sky using measurements of colour changes taken from the top of the university’s Pariser Building.
In mice exposed to the artificial sky, their body temperature was warmest just after sunset − showing body clocks working normally.
Peak temperature occurred later when twilight was recreated using the correct colour as well as intensity of light, showing the importance of colour to the body clock.