NIOSH Training for Nurses on Shift Work and Long Work Hours

Improve Sleep by Avoiding Light

Light strongly affects circadian rhythms. Morning light strikes the retina of your eye and sets up a chain of circadian hormonal reactions that signal the body to begin daytime alerting processes. Blue light, a wavelength component of daylight, has the strongest effect.⁶ (See Module 2 for more information.) You can prevent blue light from reaching the retina by wearing blue-light-blocking sunglasses. Researchers have developed glasses with special lenses for this.^7,8 Other devices may become available in the future. You can consult with a sleep disorders specialist for guidance on the type of sunglasses to use. Some researchers are concerned that if you are sleepy after night shift, the dark sunglasses could increase sleepiness and increase risk for drowsy driving which is dangerous. Other researchers recommend that night shift workers wear dark sunglasses on their way home from work. This strategy prevents your circadian rhythms from triggering the daytime-alerting processes and enables you to sleep a little longer and better after the night shift. The safest approach is to use dark sunglasses after night shift only if you have someone to drive you home. Put the dark sunglasses on before you go outside, and keep them on until you are back in a dark room.

A very dark bedroom facilitates sleep. But plan for safety if you have to get up in the dark: keep the path to the bathroom clear. If you have to get up to use the bathroom, a dim red nightlight will be less likely to trigger circadian daytime alerting and disturb your sleep. Otherwise, you could wear blue-light-blocking glasses while you are up.

If you watch TV or sit at a computer screen late at night or early in the morning, its light could be sufficient to trigger your circadian alerting signal. Avoid using the computer an hour or so before bedtime, especially if you tend to have trouble falling asleep or you want to sleep longer or better. Also, do not let the light or sound from the cell phone disturb your sleep.