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The Importance Of Sleeping In Total Darkness

The Importance Of Sleeping In Total Darkness

Light exposure is like a drug. And it can affect your health in so many ways, especially while sleeping. Sleep expert Charles A. Czeisler of Harvard Medical School said it perfectly, “every time we turn on a light, we are inadvertently taking a drug that affects how we will sleep and how we will be awake the next day.”

Recent research has found that sleeping in total darkness can protect your heart while you sleep. Researchers found that even a tiny amount of light exposure while sleeping increases the risk of heart disease and diabetes.

When a bedroom is bright, the heart rate rises and the body cannot rest properly. Even moderate ambient lighting during sleep can damage cardiovascular function and insulin resistance, which is worse than sleeping in a dimly lit room each night.

This study demonstrated that even just one night’s exposure to moderate room lighting could affect glucose and cardiovascular regulation, which are risk factors for diabetes, heart disease, and metabolic syndrome. The amount of light exposure during sleep should be avoided or minimized.

Light exposure during the day increases heart rate by activating the sympathetic nervous system, which increases alertness and heart rate. This study suggests that exposure to light during sleep causes a similar effect.

Researchers found that sleeping in a room with moderate lighting causes your heart rate to increase. As a general rule, you have a lower heart rate at night and a higher heart rate during the day. 

Despite sleeping, your autonomic nervous system is active. That isn’t good. Melatonin production is suppressed, and daily rhythms are disrupted by light exposure, leading to physiological and behavioral changes in the human body. 

Light also plays a critical role in controlling the circadian rhythm, the body’s internal clock that signals when to be alert. This alertness increases your heartbeat.

Your Brain Detects Light Even When Sleeping

Your Brain Detects Light Even When Sleeping

During the day and at night, our physiology is regulated by the sympathetic and parasympathetic nervous systems. During the day, the sympathetic system takes over, and at night the parasympathetic system repairs the body.

The researchers found that insulin resistance is caused by waking up from a lit room the night before. In insulin resistance, cells in the muscles, fat, and liver do not respond to insulin well and cannot use sugar from the blood as energy. In response, the pancreas produces more insulin—eventually, blood sugar increases.

study published in 2016 used data from the US Defense Meteorological Satellite Program. The researchers combined satellite images of nighttime illumination with WHO data on overweight and obesity prevalence rates for females and males. According to the study, artificial light at night is associated with country-wide overweight and obesity rates.

To explain why this happens, the present study demonstrates an implied mechanism. It shows that light exposure during sleep affects glucose metabolism.

They did not rest properly during sleep. The study participants were unaware of their bodies’ biological changes at night. However, their brains were aware of them. The brain acted as if they were experiencing light and erratic sleep.

The Significance Of Sleeping In Total Darkness

The Significance Of Sleeping In Total Darkness

The new study announced that sleeping people are often exposed to artificial light at night, whether from indoor light-emitting devices or outside sources, especially in large cities. A bedside lamp or television is used by up to 40 percent of people while they sleep.

The importance of light exposure during the daytime is equally as vital as sleep, nutrition, and exercise. However, the study shows that even a little light can harm the heart and endocrine health at night.

Over one night, participants were compared while sleeping with either a 100 lux (moderate light) or a 3 lux (dim light). 

According to the researchers, moderate light caused a higher level of alertness in the human body. The heart rate and force of contraction increased during this state, and oxygenated blood flowed faster to the blood vessels.

The results of this study are significant, especially for those living in cities where nighttime exposure is increasing. Fix the problem if you can see well in your sleeping area. Sleeping in total darkness will make you or keep you healthy.

Melatonin Is A Potent Antioxidant

As mentioned earlier, light exposure while sleeping suppresses melatonin (the hormone of darkness) production. Since melatonin is also a potent antioxidant, its suppression will cause oxidative stress to accumulate in your body, resulting in unwanted inflammation. Sleeping in total darkness is a beneficial solution to increase melatonin production.


According to the research, it is best to keep our bedrooms as dark as possible. Turn off all your gadgets that emit light and close your blinds to accomplish this. Avoid reading on your cell phones, tablets, and laptops within two hours of bed.

Sleeping in total darkness may just be the remedy to help your aches, pains, allergies, etc. You will wake up refreshed and with more energy.