Festival, Light And Health Hazard

Light is an essential element of our lives. It is not only necessary for vision but also plays a crucial role in regulating our biological clock, also known as the circadian rhythm. Maintaining the circadian rhythm is important as it regulates our sleep-wake cycle, hormone production, and numerous physiological processes. Planet Earth has been inundated with light from the sun and is the primary source of energy. Sunlight warms us, produces weather patterns, helps plants produce oxygen and food from carbon dioxide and water, produces electricity, and assists our movement in the daytime.

Over two billion years ago, cyanobacteria used sunlight in photosynthesis to make oxygen and carbohydrates from carbon dioxide and water. The process, consequently, made the large quantities of oxygen in the atmosphere hence allowing life needing oxygen for survival to evolve and thrive. The plants use chlorophyll to achieve the same result today which keeps the atmosphere breathable and provides food energy for us and all other advanced forms of life. Light exposure, particularly in the form of natural sunlight, is essential for maintaining a healthy circadian rhythm. 

However, the increasing use of artificial light sources, such as LED lights, has raised concerns about the potential health effects of light exposure. The importance of light is enormous in our lives. It is almost not possible for a human to survive without light and at the same time excessive or over-lighting has been associated with adverse effects on human health. In 2018, the Global LED Lighting Market was valued at USD 51.79 billion and is expected to reach USD 112.5 billion by 2024, with a CAGR of 13.75 per cent during the forecast period from 2019-2024. It has been estimated that the transition to energy-efficient LEDs will save USD 18 billion in electricity costs and avoid more than 160 million tonnes of carbon dioxide emissions each year.  

Lighting market

The fastest-growing lighting market will be in Latin America while the largest market will be the Asia Pacific in the projected period. Moreover, the effects of light on health and the potential risks associated with prolonged exposure to artificial light have not been given due importance. The human body is designed to function in sync with the natural light-dark cycle. A group of cells in the brain called the suprachiasmatic nucleus (SCN) regulates the circadian rhythm in our body. The SCN receives information about the light-dark cycle from the eyes and sends signals to other parts of the body to regulate various physiological processes. 

Exposure to natural sunlight during the day helps to synchronise the circadian rhythm, promoting alertness and wakefulness during the day and restful sleep at night. However, the increasing use of artificial light sources, particularly blue light, has disrupted the natural light-dark cycle. Blue light has a short wavelength and a high energy level, making it more effective at suppressing the production of melatonin, a hormone that regulates sleep. 

Exposure to blue light at night, particularly from electronic devices such as smartphones and tablets, can disrupt the circadian rhythm, leading to sleep disturbances and other health problems. Studies have shown that exposure to artificial light at night can increase the risk of various health problems, including obesity, diabetes, and cardiovascular disease. A study published in the Journal of Clinical Endocrinology and Metabolism found that exposure to artificial light at night can disrupt the production of hormones that regulate appetite, leading to increased food intake and weight gain. 

Another study published in the Journal of Pineal Research found that exposure to artificial light at night can increase the risk of breast cancer in women. In addition to disrupting the circadian rhythm, exposure to artificial light can also cause eye strain and other vision problems. The blue light emitted by electronic devices can cause digital eye strain, a condition that causes dry eyes, blurred vision, and headaches. 

Prolonged exposure to blue light can also increase the risk of age-related macular degeneration, a condition that can cause permanent vision loss. To minimise the potential health risks associated with artificial light exposure, it is important to take steps to promote a healthy circadian rhythm. This includes limiting exposure to artificial light at night, particularly from electronic devices. Using blue light filters on electronic devices and wearing blue light-blocking glasses can also help to reduce the impact of artificial light on the circadian rhythm. Exposure to natural sunlight during the day can also help to promote a healthy circadian rhythm and improve overall health. 

Take Home Message

Both natural as well as artificial lights are necessary for optimal human activities. The artificial light at night prevents falls and injuries to elderly people.  It has been recommended to use 130 to 150 lumens per square foot of workspace. A 40-watt fluorescent bulb emits about 2,200 lumens and a 60-watt incandescent bulb gives 800 lumens. The Ministry of Urban Development of Nepal has requirements for lights and ventilation in the National Building Code, 2015. Guidelines for natural and artificial lighting requirements for residencies, different workplaces, and special purpose buildings in Nepal are lacking and, thus, there is a need to make the general public aware of safety, optimum human activities, and healthy life.

Light plays a crucial role in regulating our biological clock and maintaining overall health. However, the increasing use of artificial light sources, particularly blue light, has raised concerns about the potential health effects of light exposure. Prolonged exposure to artificial light at night can disrupt the circadian rhythm, leading to sleep disturbances and other health problems. To minimise the potential health risks associated with artificial light exposure, it is important to take steps to promote a healthy circadian rhythm, including limiting exposure to artificial light at night and increasing exposure to natural sunlight during the day.

(Dr. Lohani is the Executive Director at Health Concern, Nepal. lohanis@gmail.com)