How Do Sleep, Circadian Rhythms and Bright Light Work Together?


Lifehacker has a story linking our circadian rhythms and light.

Lifehacker reported on a Harvard study that shows bright light during the day is good for you, and helps you sleep at night.

The Harvard study is backed up by many other studies that already point to this. The researchers at Harvard says that for workers, bright light in the office can make a big difference to their night-time sleep.

sleeping boy with dog

I wonder if the daylight during the day also helps to stop us sleeping in the daytime? You would think so, but if I am overtired, nothing will stop me from sleeping – I know, because it just happened to me about 15 minutes ago!

circadian rhythm clock
circadian rhythm clock

The Lifehacker story said:

A number of studies on circadian rhythm support this. In one study, researchers compared the sleep quality of 27 people who worked in windowless environments with 22 workers exposed to significantly more daylight.

They reported:

Workers in windowless environments reported poorer scores than their counterparts on two SF-36 dimensions—role limitation due to physical problems and vitality—as well as poorer overall sleep quality from the global PSQI [Pittsburgh Sleep Quality Index] score and the sleep disturbances component of the PSQI. Compared to the group without windows, workers with windows at the workplace had more light exposure during the workweek, a trend toward more physical activity, and longer sleep duration as measured by actigraphy.

The Pittsburgh Sleep Quality Index relates to sleep quality, in psychiatric studies. They investigated, analyzed and defined it at the University of Pittsburg.