Can you remember a time when you are lying in bed or in a dark room starting with the screen of your mobile phone or your laptop? Maybe you have an email to send right before you go to bed, or do you have to finish that last stage of Candy Crush before retiring to bed?

The light that your phone or computer emits is called ‘blue light’ and is harmful at night. Let’s see why.

Your normal circadian rhythm

For millions of years, the sun has been the primary source of light for all creatures on earth, including humans.

It is rare that we need artificial light sources during the day, unless we are in a closed space without windows. While the day is ideal for light, the night is a different story. How many of you can remember a time when we didn’t have cell phones, advanced electronics, or energy efficient light bulbs (CFLs), and we relied on good old light tubes or low wattage bulbs to light our homes?

Our body has an internal clock that makes it active during the day and sleepy at night. This circadian rhythm is responsible for keeping us alert and alert, and is highly dependent on external light. The average duration of a circadian rhythm is 24 hours and a quarter (24 hours and 15 minutes). This varies for people who have night hours or those who work night shifts.

Our circadian rhythm depends on the release of melatonin, a hormone released in the brain that helps us sleep. During the day, hormone levels are very low, while at night they are high and help you fall asleep. However, if you are exposed to light for long hours at night looking at your phone or computer or even sleeping with the light on, your melatonin levels will remain low. This could disrupt your circadian rhythm, confuse your brain, and keep you awake longer.

Blame the blue

There are various wavelengths of light emitted by electronic devices and energy saving light bulbs. However, blue light seems to be the most noticeable. Interestingly, CFLs contain about 25% of harmful blue light and LEDs contain about 35% of harmful blue light.

In an experiment carried out at Harvard University, exposure to blue light for 6.5 hours was found to suppress the release of melatonin for twice as long as the same duration of green light. It also changed the circadian rhythm in 3 hours. In another Toronto experiment, people who were exposed to bright light but wore blue goggles had the same melatonin levels compared to those in a dimly lit room.

Another study that looked at teens who used their cell phones or devices at night found that exposure for just one hour to blue light reduced melatonin levels by 23%. In two hours, it was further reduced to 38%.

Similarly, red light appears to have almost no effect on circadian rhythm compared to blue light. Some people even advise using a dark red light as a bed light, as it would not disrupt sleep patterns.

The harmful effects of blue light

So what effect does blue light really have on the body? Sadly, it’s not just about it affecting sleep. Excessive blue light exposure has now been linked to weight gain, heart disease, depression, and even some forms of cancer.

Melatonin has anticancer properties and low levels of it at night can increase the risk of cancer. In one study, women who worked night shifts had low melatonin levels and a 50 to 75% higher risk of developing breast cancer in their lifetime.

People who are exposed to blue light at night have a lower level of insulin production. This means that the snacks you eat when you are up late are not broken down into glucose or used by the body. Instead, they turn into fat and increase body weight. Not only that, low insulin levels mean that diabetes can be a complication of blue light exposure.

But not only adults are affected. Children also seem to be very affected by blue light. Children and babies who watch their favorite cartoons on their mobile phone are exposed to a lot of blue light. This can penetrate the eye and damage the back of the eye, that is, the retina. It leads to a condition called macular degeneration, which is one of the leading causes of blindness in adult life. It can also accelerate the development of cataracts.

Damage prevention

So what can you do to prevent the harmful effects of blue light on your health? A few simple steps are enough. Make sure to spend a lot of time in daylight. You can move your work desk near the window. Avoid using your phone or laptop for at least 3 hours before going to bed. This will allow your brain to increase the levels of melatonin and this will help you fall asleep sooner.

These days, apps are available for phones that filter out blue light and only emit less harmful rays.

Do your best to expose yourself to lots of bright light during the day. Natural light is the best for you. On the weekends, try to avoid being a television addict and get out of the house with the family.

If you must use a bed lamp, use a red one instead of a blue one. Red light has the least effect on melatonin and does not affect the circadian rhythm. Avoid using LED lights too often.