Blue light has a short wavelength and a high amount of energy. Adequate exposure to the natural blue light is known to lift your mood, attention and reaction times during the day.
Adequate exposure to the natural blue light is known to lift your mood, attention and reaction times during the day. However, at night, blue light exposure may be harmful to health.
- It regulates the circadian rhythm (body’s natural sleep-wake cycle), but excess exposure to blue light late at night (through electronic gadgets) can disrupt your biological clock. Further, it can also lead to sleeping and daytime tiredness.
- Blue light, when obtained from sunlight, protects eye health in children and prevents myopia or short-sightedness. The same blue light from smartphones, laptops and eReaders can cause eye damage.
What is blue light?
Sunlight is made of different colors, including
These lights combine to form the white light that we see. Each of these lights has different wavelengths and energy. Red light has a longer wavelength and less energy. On the other end of the spectrum, blue rays have a shorter wavelength and higher energy. White lights expose your eyes to a greater amount of blue light.
What are the other sources of blue light?
Apart from sunlight, the other sources of blue light include
- Fluorescent light
- Compact fluorescent light (CFL) bulbs
- Light-emitting diode (LED) light
- Flat-screen LED televisions
- Computer monitors, smartphones and tablets
Even though blue light exposure from screens is less than the amount of exposure from the sun, there is increased concern about the damaging effects of screen exposure mainly due to
- Long-term screen exposure.
- Proximity to the screen.
- Duration and frequency of exposure.
According to the National Eye Institute, children absorb more blue light from digital devices than adults.
How does blue light affect mental health?
Experts claim that nighttime exposure to blue light disrupts your circadian rhythm or sleep–wake cycle. Circadian rhythm disturbance can lead to symptoms of depression or feeling low. Circadian rhythm plays a crucial role in several brain and behavioral processes, such as neurotransmission and hormone secretion.
Studies conducted on mice have shown that mice exposed to dim light for four weeks showed signs of depression compared to mice exposed to the normal light-dark cycle.
Blue light also affects the body’s release of melatonin—a hormone that regulates the sleep cycle. Thus, it can lead to difficulty falling asleep, which may increase the risk of mood disorders such as depression and anxiety. Getting adequate sleep is essential for balanced mental health.
On the contrary, blue light exposure during the day may help treat seasonal affective disorder or SAD. Studies have shown 20 minutes of blue light exposure in the morning helps ease SAD symptoms.
How to protect yourself from the harmful effects of blue light
If your job involves continuous exposure to computer or smartphone screens, here are some tips to reduce the damage from blue light.
- Reduce screen time by taking frequent breaks to give your eyes a rest.
- Use screen filters available for smartphones, tablets and computer screens.
- Wear yellow-tinted blue-light blocking glasses made especially for blocking blue light emitted from computer screens.
- Talk to your doctor about blue light protection and digital device use.
- Adjust screen brightness.
- Switch your LED light bulbs for bulbs that have a warmer hue.
- Expose yourself to sunlight during the day to adjust your circadian rhythm.
Medically Reviewed on 4/15/2021
Mental Health America
UC Davis Health