The effect of light on a person’s sleep cycle or ‘circadian rhythm’ was the focus of a white paper issued by Philips, a leader in lighting.

It compiled key insights from over 10 years of ongoing research, revealing that the amount and quality of light a person is exposed to everyday may be responsible for their ‘Sunday morning blues.’

Lighting, whether natural or artificial, affects all life on our planet, it said. In humans, it plays a crucial role in regulating our circadian rhythm, one of our natural biorhythms otherwise known as the body clock.

The circadian rhythm is not naturally in sync with the artificial clock. Instead, it is a little slower running for 24 hours and 30 minutes on average.

This means we are naturally inclined to sleep and wake 30 minutes later each day. If this slower rhythm is not regulated then by the end of the week, the sleep/wake cycle could be off by more than two hours.

Alarm clocks offer one way to manage the time lag created by the naturally slower circadian rhythm. But, it has been recently discovered that a specific quality of light hitting the photoreceptors in a persons’s eyes not only regulates the internal body clock, but can actually reset it every single day.

The high intensity artificial blue-rich light is capable of resetting the body clock because of its qualitative resemblance to natural morning light.

With a natural tendency to sleep in, the modern nine to five lifestyle means a person may be getting too little sleep during the working week and lying in at the weekends. Longer sleep at the weekend may compensate for the lack of rest during the week, but can reset a later circadian rhythm the following week, resulting in that ‘Sunday morning blues’ feeling.

Lucy Schlangen, light and sleep scientist at Philips Research, said: “The message from nature is clear. Our bodies have evolved a kind of steering wheel, constantly adjusting the sleep-wake cycle, driven by light, allowing us to adapt to the differing daylight lengths during the seasons.

“We can help regulate our body clock through lighting by providing light injections at appropriate times, for instance through brighter office lighting on Sunday mornings.”

Exposure to blue-rich morning light can speed up our circadian rhythm to wake us up earlier and improve the daily functioning of people with an early morning lifestyle, said the report.

Derk Jan Dijk, lighting expert professor, University of Surry, added: “Dimming lights a few hours before bedtime facilitates a more rapid onset to sleep and it will prevent your body clock from being shifted to later hours. If you want to shift your clock to earlier hours it is good to be exposed to light and specifically high intensity blue-rich light, when you wake up.”

Philips dedicates five per cent of its lighting sales revenue to R&D, and is testing and developing a series of energy efficient lighting products for homes, offices, schools and hospital environments that can variously improve alertness, productivity, calm, sleep and mood. - TradeArabia News Service