Night-Time Light Exposure can be Unhealthy

By Amirah Zahirah Binti Mohd Azar

Light is the most significant external factor that influences sleep. Most individuals are intuitively aware that without light, they can sleep easily and faster than with the lights on. Yet, there are still several individuals, most people with anxiety, who are unable to sleep in pitch darkness, and think that sleeping with the lights on is the best way for them to feel more relaxed and comfortable. Lights can be from many sources around us such as ceiling lights, streetlights, and the light from a television, including the blue light that is emitted from devices, which poses great harm to an individual. A lifestyle that exposes us to light while sleeping might result in a dramatic effect on our sleeping cycle and our health and well-being. This article will explain how nighttime light exposure can be hazardous in a variety of ways and how to cope with it for those who refuse to be in the dark at night. 

The issue arising is clearly related to the United Nations Sustainable Development Goal 3 (SDG: Good Health & Well-Being) because sleeping with the lights on has been proven by many studies that it is harmful for the doers in a variety of ways and could predispose the individuals to chronic diseases. People exposed to light during sleep, for example, will have raised heart rates throughout the night and greater insulin resistance in the morning, indicating that they are having difficulty bringing their blood sugar levels back to the normal range. 

SDG Goal 13 on the other hand, emphasizes on taking urgent actions to combat climate change and its impact. Electricity generation accounts for over 40% of worldwide carbon dioxide emissions, with fossil fuels being burned to provide the heat needed to power steam turbines. Carbon dioxide, the major heat-trapping “greenhouse gas” which is responsible for global warming, is produced when these fuels are burned. 

According to a new research study by Dr. Phyllis Zee, senior author of the study and director of Northwestern University’s Center for Circadian and Sleep Medicine, one night of sleep with only a moderate level of light may have negative consequences on cardiovascular and metabolic health. 

The negative impact of sleeping with the lights on is found on cardiovascular which indicates that some people will have some issues as they experience increased heart rate throughout the night. The research study also found that even a modest quantity of light was sufficient to activate the sympathetic arm of the autonomic nervous system, which oversees the body’s fight or flight reaction. This system is intended to cool down during sleep when the body enters a parasympathetic state, which causes the heart rate and breathing to slow down. However, a tiny amount of light hinders these from happening as it stimulates and alerts the nervous system.

The researchers also studied and measured the level of melatonin, a hormone that aids in the timing of circadian cycles and promotes sleep. This type of hormone is usually repressed during the day and increases at night. This is one of the possibilities to support that being exposed to light at night could disrupt one’s metabolism. Dr. Charles Czeisler, chief of the Division of Sleep and Circadian Disorders at the Brigham and Women’s Hospital in Boston and a professor at Harvard Medical School has concluded in newly published research that the detrimental effects on metabolism found in their study participants of 40,000 women over the course of three weeks were mostly due to changes in circadian rhythms and not due to sleep deprivation. 

Besides, Dr. Abhinav Singh, a Sleep Physician, also agreed that light exposure at night might makes it difficult for transition between sleep cycles, which may eventually lower sleep quality. Too much light can trigger frequent awakenings, disrupt the sleep cycle and limit the amount of time spent in deeper, more restorative phases of sleep.

However, there are still some who prefer to sleep with the light on because of their fear of the dark and feelings of comfort. In these cases, the lights should be turned down to the lowest level. Even if these people still require bright light to fall asleep, a timer-controlled light may be advantageous so that most of the sleep time is spent in darkness. These individuals can also opt to cover their eyes using a close-fitting eye mask, which may also contribute to better quality of sleep. If there are any cases of having a severe phobia of the dark, consultation with a mental health professional may be able to help them in building a strategy to reduce anxiety before night.

In a study, it was found that 42% out of 1,000 American adults slept with the lights on because they feared the dark and were worried of any intruders, without realizing how serious exposure to the light during their sleep was to their health. It is unfortunate that this lifestyle issue is not recognized by most people as there is less awareness about it. 

Governmental and non-governmental organizations need to take action to spread awareness on this issue either in newspapers, social media, or magazines. They can also organize a campaign that encourages people to have better quality sleep by switching off all lights and getting them to sleep in pitch darkness. 

Educational institutions and parents need to educate children by providing them with earlier exposure and education related to the unhealthy habit of sleeping with the lights on, so that they may easily apply it when they grow up since they will become used to it. 

Having regulations by the government to urge people to sleep in darkness is not recommended as this will cause difficulties for people. Therefore, raising awareness of this issue is one of the best ways to promote good sleep and a healthy lifestyle for all.

In summary, light sleepers need to change their lifestyles to a better one by normalizing sleeping with the lights off. It not only can improve the quality of sleep, but also hinders oneself from the risk of getting eye strain, weight gain, cancer, and many other illnesses due to the sleep disorder. There are many ways that individuals can develop to ensure the best possible sleep every night even if they are not able to sleep in the dark. Thus, it is believed that, with more awareness created on this issue, everyone can get better sleep, which is significantly important to ensure productivity and sufficient energy during the daytime. ***

(Amirah Zahirah Binti Mohd Azar is a student from Kulliyyah of Economic and Management Sciences (KENMS). The article is part of the ‘Sustainable Development Goals’ course. The views expressed here are those of the writer/author and do not necessarily represent the views of IIUMToday,)

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