Light may lull the troubled sleeper right to sleep! Prior to the discovery of electricity, light from the sun controlled sleep-wake cycles.  Artificial light disrupts this natural rhythm, not only in our external environment but also inside our bodies.

Questions to Ask:
  1. Are you aware of outdoor lighting conditions?
  2. What effect does indoor lighting have on you?
  3. Do you feel sleepy when it gets dark outside?
  4. What time do you shut off electronic screens (TV, phone, computer)?

The Circadian System

Our circadian system controls the processes within our body that follow a 24-hour cycle: hormone regulation, body temperature, and sleep/wake cycles.

How Light Affects the Circadian System

A collection of cells called the suprachiasmatic nuclei (SCN) send signals throughout our body to help regulate us to our 24-hour day. Light travels first to our retina, then to our SCN, and ultimately to the pineal gland, which releases melatonin, the hormone that makes us feel sleepy. This is how light directly affects the circadian system.

How many hours per day do you spend indoors? Most Americans spend 90% of their time indoors (U.S. Environmental Protection Agency). Exposure to artificial indoor light suppresses melatonin production, thereby disrupting our ability to sleep, regulate body temperature, blood pressure, and glucose levels. Research is connecting disrupted circadian systems to a host of health impairments including cancer, obesity, diabetes, heart disease, depression, mood and sleep disorders, decreased physical and mental performance, decreased productivity and irritability. The number one culprit that disrupts our circadian system is night-time exposure to blue-rich light from screens: namely televisions, phones, and tablets. The blue part of the light spectrum suppresses melatonin to the greatest extent and the LED lights, acclaimed for their energy efficiency, produce more blue light than incandescent or fluorescent lights.


Try these three things:
1) Get as much natural lighting as possible! Aim to get at least 60 minutes of outdoor light exposure per day.  When you are inside, try to position yourself near a window.
2) Seek indirect lighting: Direct lighting can strain our eyes and decrease productivity. Indirect lighting distributes light upward towards the ceiling and then reflects it back downward, providing even illumination without eye-strain.
3) If you’re on the computer late at night, consider downloading software that regulates your computer’s color display to sync with our 24 hour days. F.lux is free and can be downloaded at


GIG DESIGN | Occupational Performance


DESIGN^interceptive | Consider your behavioral standards towards lighting through exploration of your behavior to lighting.


DESIGN^body position | Consider the patterns required of your body as you interact with the effects of lighting during work tasks.


DESIGN^under responsive | Consider your body capacity needs with lighting to attend to your task.


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