Faculty researchers have revealed that the colour of light has a major impact on how our body clock measures the time of day.
It’s the first time the impact of colour has been tested. The research, published in PLOS Biology, demonstrates that the colour of light provides a more reliable way of telling the time than its brightness.
Faculty members, led by Dr Timothy Brown, looked at the change in light around dawn and dusk to analyse whether colour could be used to determine time of day. Their key discovery was that light was reliably bluer during twilight hours, compared to daytime.
The team recorded the electrical activity of the body clock of mice while they were shown different visual stimuli. They found that mice were much more sensitive to changes between blue and yellow in the colour of light, than to its brightness.
The scientists then created an artificial sky which imitated the daily changes in colour and brightness. Mice were placed underneath the synthetic sky for several days whilst their body temperatures were recorded.
Researchers found that the highest temperatures occurred just after night fell – when the sky had turned a darker blue, optimal for a nocturnal animal. When only the brightness was altered, the mice became active before dusk, demonstrating that their body clock wasn’t properly in sync with a normal day/night cycle.
The team concluded that colour must therefore play a role in the determination of the time of day.
On the importance of the research, Dr Brown says:
“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 to the change in brightness but using new experimental tools and a psychophysics approach we were successful.”
“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 travellers wanting to minimise jet lag”