Let the Sunshine in to Sleep at Night

In the 1960’s, the musical Hair featured a song titled Let the Sunshine In. Little did we know back then that it might become a clarion call for modern day architecture. According to a recent study, poorly lit and windowless work environments can have significant adverse mental and health-related outcomes. The key appears to be the effect of daylight on our sleep.

The researchers studied 49 workers for a period of two weeks. Half were in a windowless work environment and the others in workplaces with significantly more daylight. They were studied with an actigraph, which is a motion detector that differentiates sleep from wakefulness. The researchers also administered questionnaires that monitor quality of life and quality of sleep during this period.

The results were striking. Workers in windowless environments scored poorly with regards to quality of life. They were more likely to complain of physical problems and fatigue. Most importantly, they demonstrated shorter sleep duration as measured by the actigraph. This is in agreement with other studies that have demonstrated that short sleepers have more ills that are physical and are more fatigued than normal sleepers are. What is most interesting is the influence of workplace lighting on their sleep.

Why does light exposure affect sleep? It probably has to do with our circadian clocks. Light is the strongest stimulus of all in maintaining a stable sleep/wake schedule. Specifically, light exposure during the day, especially in the morning, helps us to fall asleep at a regular time each night. It would appear that workers in poorly lit environments do not have this stimulus and as a result, their sleep is affected.

Poor sleep results in elevation of stress hormones such as cortisol, impairment of glucose metabolism, increased appetite, as well as increased fatigue and decreased mental alertness. All of which, as the authors point out, can lead to increased error rates and injury in the workplace environment.

Why is this important? It is the first study to accurately reveal the negative effects of a poorly lit environment on sleep and thus health. It should motivate architects to bring more light into office buildings and might encourage workers to avoid poorly lit cubicles. If you are stuck in such a building, you might consider increasing the amount of artificial light in your workspace. Alternatively, if weather permits, go outside for your morning coffee break or lunch. Like the song says, let the sunshine in.

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