Blue Light and Sleep: What’s the Connection?

Sleep is one of the pillars of optimal health.
However, people are sleeping much less than they did in the past. Sleep
quality has also declined.
Poor sleep is linked to heart disease, type 2 diabetes, depression, and
obesity.
The use of artificial lighting and electronics at night may contribute to sleep
problems. These devices emit light of a blue wavelength, which may trick your
brain into thinking it is daytime.
Many studies suggest that blue light in the evening disrupts your brain’s
natural sleep wake cycles, which are crucial for optimal health.
This article explains how blocking blue light at night can aid your sleep.

Blue Light Disrupts Your Sleep
Your body has an internal clock in the brain which regulates your circadian
rhythm — the 24-hour biological cycle that influences many internal functions.
Most importantly, it determines when your body is primed for being awake
or asleep.
However, your circadian rhythm needs signals from the external environment
— most importantly daylight and darkness — to adjust itself.

Blue-wavelength light primarily stimulates sensors in your eyes to send
signals to your brain’s internal clock.
Keep in mind that sunlight and white light contain a mixture of various
wavelengths. They each have a significant amount of blue light.
Getting blue light — especially from the sun — in the daytime helps you stay
alert while improving performance and mood.
Blue light therapy devices may help treat depression, and blue light bulbs
have been shown to reduce fatigue and improve the mood, performance, and
sleep of office workers.
Yet, modern light bulbs and electronic devices – especially computer
monitors – also produce large amounts of blue light and may disrupt your
internal clock if you are exposed during the evening.
When it gets dark, your pineal gland secretes the hormone melatonin, which
tells your body to get tired and go to sleep.
Blue light, whether from the sun or a laptop, is amazingly effective at inhibiting
melatonin production – thus reducing both the quantity and quality of your
sleep.
Studies link melatonin suppression in the evening to various health problems,
including metabolic syndrome, obesity, cancer, and depression

SUMMARY Blue light in the evening tricks your brain into thinking it is
daytime, which inhibits the production of melatonin and reduces both the
quantity and quality of your sleep.