The spectrum of light emits all colors. Each color within the spectrum represents a different wavelength. Each wavelength of color produces various effects on our anatomy, as well as our health and well-being. It is important to note, however, that not all colors of light have the same effect! Blue light is a perfect example. Even though it is environmentally friendly, it can have negative effects on our sleep. It may, also, hold the potential to cause disease.

Prior to the advent of artificial lighting, human beings received most of their light exposure from sunlight. In the evenings, lights were dim or non-existent. In the present day, many cities around the globe are well-illuminated throughout the darkest hours of nighttime. Unfortunately, the unknown costs may be at our own expense!

The absence of light in the evenings supports the human body’s natural ‘circadian rhythm’, allowing us to reach a depth of sleep for the hours we spend resting. During our daytime hours, the wavelength of blue light is beneficial because it boosts our attention span, reaction times, and mood. Conversely, at night, the same wavelength seems to be quite disruptive to our body’s natural cycle.

In recent decades, the explosion of electronic devices with screens, energy-efficient lighting, and even street lights are all responsible for increasing our exposure to blue wavelengths.

Exposure to excess light is responsible for suppressing the secretion of melatonin, a hormone that influences circadian rhythms. Small amounts of light still produce these effects. Even eight lux, a level of light that is less than most table lamps, blue light’s wavelength can negatively affect sleep quality. According to Harvard sleep researcher, Stephen Lockley; ‘Light at night is part of the reason so many people don’t get enough sleep.’

Because so much of our push towards working late and using energy-efficient lighting seems to run counter to the body’s needs, taking steps to protect the sleep cycle is, for some, an imperative.

Avoid looking at a computer screen or excessive light exposure for 2-3 hours prior to sleeping. If you just have a light, opt for a soft, red light as it doesn’t seem to have the same effect as blue and green wavelengths. If you must use electronic devices at night or work an overnight shift, consider wearing glasses that will reduce the blue wavelength. One source suggests using the 20-20-20 rule, whereby a person takes a 20-second break every 20 minutes to look at something 20 feet away.

Conversely, exposing yourself to abundant bright light during the day will enhance your ability to sleep well at night, and improve your overall mood and energy levels during the day.

Footnotes / Endnotes:

Harvard Health Publishing – Harvard Medical School – Harvard Health Letter – ‘Blue Light has a Dark Side’ Stephen Lockley: Harvard Sleep Researcher –

‘Does Blue Light Actually Affect Your Health?’- Beth Skwarecki –

Photo Attribution – 

‘Does Blue Light from Screens Ruin Sleep?’ [CC BY-SA (]

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Advocate for clean water, sustainable living, renewable energy, as well as a believer in healthy living, yoga, tiny homes, and the conservation of Florida's natural resources! ~ Florida is in my HEART & SOUL!