Office lighting experiment suggests workers sleep longer when exposed to more daylight


A team of researchers affiliated with several institutions in the U.S. has found that office workers sleep more hours each night when exposed to more sunlight during the day. In their paper published in the International Journal of Environmental Research and Public Health, the group describes their experiments in real office buildings and what they learned from them.


Prior research has shown that when office workers are exposed to minimal natural light during their shifts, they tend to sleep less at night than people who are exposed to more sunlight during the day—they also tend to perform less well on cognitive tests. Prior research has also shown that children exposed to more sunlight during the day tend to sleep longer than those who see little daylight. In this new effort, the researchers sought to learn more about the sunlight/sleep connection by carrying out an experiment in two adjacent offices in an office building in Durham, North Carolina.


The experiments involved testing the differences in sleep patterns for people working in nearly identical office environments situated right next to each other—the only real difference was the lighting. One office had the traditional blinds that obscure much of the sunlight coming through the large glass windows. In the other office, the windows were treated with electrochromic glazing technology that allows more sunlight to pass through while still minimizing glare. For the experiment, typical office workers were asked to work in both offices for one week. At the end of the week, the workers were asked to trade offices where they worked for another week. Also, each of the workers was fitted with a wrist actigraph that measured and recorded how long the wearer was asleep each night.

這些實驗涉及檢測在幾乎完全相同的辦公環境中工作的人的睡眠模式的差異,辦公環境緊密相連,唯一真正的區別是照明。一個辦公室有傳統的百葉窗,遮擋了從大玻璃窗射入的大部分陽光。 而在另一間辦公室中,窗戶采用電致變色玻璃技術進行處理,可讓更多的陽光通過,同時仍能最大限度減少眩光。在實驗中,典型的辦公室員工被要求在兩個辦公室工作一周。一周結束后,員工會調換到另一個辦公室再工作一周。另外,每個員工都配有腕部活動記錄儀,測量并記錄佩戴者每晚睡眠的時間。

The researchers found that both groups of workers slept longer when they worked in the office with more natural lighting—on average 37 minutes longer. The researchers found that the positive effects of sunlight grew as the week wore on—scores on cognitive tests improved each day. By the end of the week, the workers scored 42 percent higher. The researchers suggest their findings show that lighting should feature more prominently in the workplace, and that doing so would benefit both workers and those who employ them.