Have you ever woken up in the middle of the night and wandered to the bathroom to find yourself blinded when flipping on the light? People respond negatively to too much light when the body wants to sleep. Light and dark have a major influence on hormone production, body temperature regulation, and the circadian rhythm.

Light affects our circadian rhythm or biological clock in accordance with light and dark. Darkness also affects our pineal gland’s production of melatonin, a naturally occurring hormone that helps induce sleep. Light signals your body to produce less melatonin. If you are working a night shift in artificial lighting, your body is likely producing too little melatonin. 1

This effect is readily seen in those suffering from jetlag. Once exposed to a new light-dark cycle in a different time zone, it takes the body a few days to adjust the circadian rhythm to the new schedule. 2 Jet lag is commonly combated through the use of melatonin supplements to compensate for slowed natural melatonin production.

Many Americans use television or other electronic devices to help them wind down and coax them to sleep. This idea is incorrect. In the National Sleep Foundation’s Annual American Sleep Poll in 2011, 95 percent of individuals surveyed between 13 to 63 years old reported going to sleep with the television on. 3

sleeping and light

How to Keep Your Biological Clock Ticking:

  • Make sure to get out in the sunlight at least once a day. Natural light allows your body to understand it is awake.
  • Do not use a computer, tablet or watch television too close to bedtime. These activities can be too alerting for the mind and may reduce melatonin production. 1
  • Do not sleep with the television on before bed. The brightness from the T.V. will slow melatonin production making it difficult to get to sleep.
  • Use dim night lights in the bedroom and bathroom so as to not blind yourself if you must get up in the middle of the night.
  • Keep the lights in your home dim or use only lamps for a few hours before bed to increase melatonin production and signal to your body that it is time for bed.
  • Purchase “black-out” or extremely dark curtains or drapes to prevent morning light from pouring in your window and potentially disrupting sleep.

Knowing that light affects the body’s ability to sleep is vital to getting a good night’s sleep. It is important to give the body the sleep it needs and make getting to sleep as easy as possible. Simple efforts to avoid light late in the day and regulate your circadian rhythm can help to avoid self-inflicted insomnia.


1. National Sleep Foundation—Lights Out for a Good Night’s Sleep; http://www.sleepfoundation.org/alert/lights-out-good-nights-sleep

2. Carskadon, Mary A. Encyclopedia of Sleep and Dreaming. New York: Macmillan Pub., 1993.

3. National Sleep Foundation—Annual American Sleep Survey (2011); http://www.sleepfoundation.org/article/press-release/annual-sleep-america-poll-exploring-connections-communications-technology-use-