Working by the window is key to good night's sleep
FOR a good night's sleep, you might want to move your office desk beside a window.
A new study shows that people who spend more of their day in natural light can get three-quarters of an hour more sleep than their counterparts.
The results make interesting reading for the one in three Irish people understood to have trouble sleeping, who might put the blame for their night-time tossing and turning on stress and the pressures of the office.
The findings, published in the Journal of Clinical Sleep Medicine, suggest access to light in the working environment may be crucial in setting the body's internal clock.
"We suggest that architectural design of office environments should place more emphasis on sufficient daylight exposure for workers in order to promote health and well-being," said Dr Ivy Cheung, of the department of neurology in Northwestern University, Chicago.
"Office workers with more light exposure at the workplace also tended to have better sleep quality, more physical activity and a better quality of life."
Scientists say a sunny day produces a light intensity of about 10,000 lux (a lux is a unit of luminance), whereas indoor office lighting typically produces only about 300 to 500 lux.
It is this difference that is causing all those sleepless minutes, according to Dr Cheung.
The findings are based on experiments involving 49 office workers, just over half of who spent the day in mostly windowless environments.
Each participant was questioned on sleeping patterns, physical activity and general lifestyle. Some of the volunteers wore watches for the duration of the fortnight-long experiment to measure their light exposure, levels of physical activity and sleep times.
Those with the most work-time light exposure slept an average of 46 minutes more per night than their light-deprived colleagues, as well as reporting fewer night-time disturbances.
Dr Neil Stanley, an independent sleep expert, said our body naturally responds differently to night and day.
"Light is essentially the thing that tells our bodies to be awake and dark tells them to go to sleep.
"The problem with office lighting is that it is not made up of 'blue' light, which is the wavelength of light you get from the sun and which controls your body clock. So you could have a very well-lit office but it does not have the same effect because it's artificial and does not contain blue light," he said.