The Effects of Lighting on Mood & Alertness

The human body is highly sensitive to changes in light. Mood and alertness depend on the body's release of hormones in response to changes in lighting throughout the day.

Circadian Rhythm

Most of the systems in the human body run on a 24-hour cycle known as a circadian rhythm, which regulates bodily functions. The brain's suprachiasmatic nucleus, popularly known as the body clock, releases certain hormones in response to light or darkness, thus telling your body when to be energetic and when to wind down.

Natural vs. Artificial Light

According to a study that appeared in the Journal of Circadian Rhythm, natural light is more effective than artificial light in positively influencing human physiology in areas like mood and alertness.

Benefits of Bright Light

In workplace settings, bright light has been shown to increase alertness, reduce fatigue and improve cognitive function.

Changes in Old Age

Changes in circadian rhythms are common in people over the age of 65. A study at Northwestern University Medical School showed that timing the exposure of light and dark throughout the day improved alertness, mood and sleep patterns in elderly participants.

Blue Light

According to a Harvard University study, the circadian system responds more to short-wavelength light, especially blue light.

References

• Lighting as Circadian Rhythm-Entraining and Alertness-Enhancing Stimulus in the Submarine Environment; Loring J. Crepeau et al.; 2006 (Conference Paper)
• Harvard University Gazette: When Light Has You Singing the Blues
• eMedicineHealth.com: Sleeplessness and Circadian Rhythm Disorder

Resources

• Journal of Circadian Rhythms