How Long Before Bed should I Avoid Blue Light?

While almost all lights have a negative effect on your sleep and sleep pattern, it is blue light that is the biggest culprit. Not all lights have the same effect. Blue wavelengths are beneficial during the day because they keep us focused and boost our attention. They also boost reaction times and mood; however, blue lights prove to be disastrous at night. They turn out to be disruptive. Unfortunately, our exposure to blue wavelengths is increasing day by day, as we get addicted to technology, devices, gadgets, etc. This is especially true for people who watch TV, surf the Internet or just while their times on their phones before they hit the bed.

How long before bed should I avoid blue light? The simple answer to this question is two to three hours. You must get out of blue lights and stop using devices that produce blue light two to three hours before you sleep.

Every individual is different and has a different circadian rhythm. On average, circadian rhythm is roughly 24 hours long. People who stay late up at night are usually called night owls; they have slightly longer circadian rhythms while people who wake up early in the morning have a short circadian rhythm.

Circadian Rhythms

Circadian rhythms can be defined as mental, physical and behavioral changes that work in a cycle. They are largely affected by light and darkness present in the environment. Sleeping at night and waking up in the day are two light-related functions of the circadian rhythm. While circadian rhythms are found in almost all the living things, our main concern here is the human circadian cycle. You will be surprised to know that plants, tiny microbes, and even bacteria have a circadian cycle. Chronobiology or the study of circadian rhythm is gaining rapid momentum today because of the rising number of insomniacs.

Biological Clocks

Biological clocks are the natural and innate timing device present in an organism. These clocks are made up of specific molecules or proteins, which interact with cells throughout the body. Biological clocks are not an organ; rather they are situated in every organ and tissue. Researchers have been able to identify similar genes in fruit flies, people, fungi, mice and various other living organisms that make up the clock’s components.

The relationship between Biological Clocks and Circadian Rhythms

People, including common people and researchers, often confuse between the biological clock and the circadian rhythm. While these two are not the same thing, they are closely related. Biological clocks are responsible for producing, managing and regulating the circadian rhythm. The biological clocks are controlled by a supreme clock known as the master clock.

Master Clock

A supreme or master clock is the clock that is present in the brain. It controls all the other biological clocks in the body of an organism. It is the responsibility of the master clock to keep all the biological clocks in sync. Without the master clock, all our biological clocks would go haywire leading to a variety of problems. In most of the vertebrate animals, including human beings, the master clock is made up of about 20,000 nerve cells or neurons. These neurons come together and form a structure known as the suprachiasmatic nucleus or SCN. SCN is located in the hypothalamus region of the brain, and it is responsible for receiving direct inputs and data from the eyes.

Does the Body have its Own Circadian Rhythms?

Yes, our body does make its own circadian rhythm; however, it is a delicate clock and is extremely sensitive to external stimuli. Natural factors within the body that produce circadian rhythms may suffer if external factors are introduced. Various environmental signals can ruin the circadian rhythm. The most significant factor that is responsible for the circadian cycle is daylight. Daylight is essential, as it can turn on and turn off genes that control the molecular structure of biological clocks including the circadian rhythm. If light-dark cycles are changed or manipulated such as if they are slowed down or are sped up, it may reset your biological clocks and may also affect the circadian rhythm.

Circadian Rhythms Affect on Body Function and Health

Circadian rhythms have a significant effect on sleep-wake cycles, eating habits, hormone cycles, digestion, body temperature and various other important cycles, systems and functions of the body. If biological clocks are disturbed, circadian rhythm gets disturbed as well. Irregular circadian rhythm and the biological clock can lead to a variety of diseases and disorders including obesity, sleep disorders, health conditions, diabetes, bipolar disorder, depression, seasonal affective disorder.

Circadian Rhythm and Sleep

Our sleep patterns are dependent on our circadian rhythm, and they help to determine how and for how long we sleep. The master clock, also known as the SCN, is responsible for making melatonin. The hormone Melatonin is responsible for making you sleepy. It receives information about light from your eyes aka your optic nerves and will relay this information from the eyes to your brain. The optic nerves can guess whether the light is more or less, which then signals the SCN to determine the nature of light.

When there is less light, for instance at night, the SCN tells our brain to produce more melatonin. More melatonin means more drowsiness. Researchers are trying to study how different shifts work differently towards different lights. For instance, researchers are trying to find how the light released from mobile devices, and other gadgets can affect the quality of your sleep.

Is Nighttime Light Exposure Bad?

According to certain studies, there exists a close connection between light at night and quality of sleep. Other studies suggest that light at night may lead to various other problems including some types of cancer, diabetes, heart disease, and obesity. While these studies are still in the primary phases, it is always better to be safe than sorry. Exposure to light at night can reduce the secretion of melatonin, which affects the quality as well as the quantity of sleep. There exists experimental evidence that lower melatonin levels may lead to cancer.

According to another study conducted by Harvard, it was found that light might lead to obesity and diabetes as well. In this study, ten people were tested by changing their circadian rhythms ever so slightly. It was soon found that there was a spike in their blood sugar levels and they entered into a prediabetic state.

It has been proven that even dim blue light can affect a person’s circadian rhythm and melatonin secretion. A simple table lamp can cause problems too. It is no wonder when people say that light at night is one of the major reasons why people don’t get enough sleep and whatever sleep they do manage to get is not satisfactory. Short sleep has been linked to increased risk for depression, along with diabetes and cardiovascular problems.

Effects of Blue Light and Sleep

Light of any kind is bad for the secretion of melatonin; however, the worst culprit is blue light at night. According to various Harvard researchers, it was found that continuous exposure of 6.5 hours to blue light can suppress melatonin twice as long as a green light of the same intensity for the same time. It was also found that blue light could change the circadian rhythm almost twice as compared to green light.

Another study on blue light was conducted by the University of Toronto where they compared melatonin levels of people who were exposed to bright light with people who wore blue light jamming sunglasses and people exposed to normal dim light. It was found that the levels of melatonin were almost the same in both groups. This provides ample evidence to the fact that blue light is indeed harmful to nighttime sleep.

If you are a night owl or work in nightshifts, it is recommended to invest in a good quality eyepiece that can block blue light. An inexpensive option for blue light blocking glasses is using orange-tinted glasses. These glasses block blue light effectively, however most of these block other colors as well, which makes them unsuitable for indoor use. If you want to invest in a special, blue light only blocking pair of glasses, be ready to shell out around $80 at least.

LED Blue Light Exposure

Blue light has many adverse health effects; however, this leads to a conundrum. Blue lights are often great for the environment, however, if they are bad for human health, then whether to use such lights or not is a controversial topic. Old-fashioned incandescent bulbs did not produce a lot of blue light; however, they were not at all environmentally friendly, in contrast to them, the bulbs that we use nowadays – LED and Fluorescents, both are environmentally friendly; however, they are not good for human health.

The physics and mechanism of these lights are impossible to change; however, it is possible to coat them with special materials and chemicals to make their light warmer and less blue. While LED lights are comparatively more efficient than fluorescents, they still produce blue light.

How to Protect Yourself from Blue Light at Night?

There are certain methods that you may use to protect yourself from blue light at night. These methods include:

Use dim red lights instead of regular night lights. Red lights are good for circadian rhythm, as they do not affect circadian rhythm and melatonin production system significantly.

Do not look at bright screens before bed. Maintain at least a two to three-hour gap between screens and bed.

If you work a night shift, invest in a good quality blue light blocking pair of glasses. If you use a lot of gadgets, install blue light filtering apps.

In all, if you take the right precautions and keep away from blue light around your sleeping time, your sleep cycle and body clock will run in a perfect manner.