How Does Lighting Affect Us?

Our bodies require a certain amount of exposure to natural light every day to function properly and create the enzymes and proteins necessary to our health, according to the Sound Sleeping website. We also need a break from light sources for our brains to produce the hormone melatonin during sleep under darkened conditions; melatonin is an essential component in the process of inducing sleep.

Light Levels and Sleep

• Sleeping with a light this bright can produce less restful sleep.

  Light is measured in a unit called a lux, the illumination required to light 1 square meter of a surface. Exposure to light during normal nighttime sleeping periods can cause a chemical reaction in your brain that makes it think it is time for it to be awake, the Sound Sleeping website states. Your sleeping/waking cycle is regulated by the brain's pineal gland, which produces melatonin. Melatonin production peaks during sleep and helps you achieve a proper sleeping/waking cycle. But if you sleep with a light on, this lowers pineal gland stimulation, resulting in lower levels of an enzyme called N-acetyltransferase, or AA-NAT, which you need to produce melatonin. So light reduces pineal gland stimulation, which results in lower AA-NAT, which in turn causes lower levels of melatonin, which results in less restful sleep.

Light Effects on Shift Workers

• Workers who do overnight shifts often suffer from disruptions in their circadian rhythms.

  Workers who do overnight shifts and sleep during the day often suffer from sleep disorders that affect their circadian rhythm and their ability to stay alert while carrying out work-related duties at night, according to S.S. Campbell of the Cornell University Medical Center's Department of Psychiatry. In his 1995 study, Campbell examined in a simulated shift-work setting whether regularly scheduled exposure to therapeutic bright lights could help overnight workers adapt more easily to the reversal of their usual awake-during-the-day, asleep-at-night circadian rhythms. His findings indicated that younger workers seemed to benefit more than middle-aged workers in achieving at least a partial phase adaption of their internal clocks, although no discernible improvement was found in work performance following the light therapy for any of the participants.

Seasonal Affective Disorder

• The American Family Physician journal, "Seasonal Affective Disorder," stated that seasonal affective disorder, known as SAD, results in its sufferers experiencing bouts of severe depression, typically in the shorter days and longer nights of winter. Light therapy has been effective in easing the symptoms of the disorder, with a typical treatment being exposure to 5,000 lux for 30 minutes to two hours early in the day.

Light, Natural vs. Artificial

• Incandescent lighting exposure can disrupt human body rhythms.

  The use of incandescent light can disrupt a person's sleeping/waking cycle, according to the Sound Sleeping website. The human body typically needs one hour of natural sunlight exposure daily to stay healthy. Full-spectrum lights that produce light similar to natural sunlight can aid in balancing the body's circadian rhythm and help you experience a full night's sleep.