Sahar Isaac and Max Kaplan-Zantopp

Too Bright To Be Sound Asleep

August 30, 2021

With cities growing larger, urban residential areas are getting louder and brighter, and it’s becoming harder to sleep at night. A new Israeli study sets out to prove that noise and light pollution are impacting your sleep schedule.

“How did you sleep?” This is more often than not the most frequent question you hear right after, “Good morning,” but it’s an important one as your answer softly determines how the rest of your day will play out or how you will feel throughout the day. With the daily hustle of work, study, and family obligations always at the forefront of our minds, it can be easy to overlook the crucial importance sleep provides our mental and physical well-being.

Depending on where you live, especially if you live in a city, there’s a good chance you live close enough to a busy street that, at times, produces loud construction or traffic noises and bright unwanted lights shining through your window that you end up having no choice but to suffer through. However, it did not always used to be like this.

“Before the Industrial Revolution, humans lived in a world where, at night, there was almost complete darkness outside, and the only noises that could be heard were the natural sounds of the animals and the weather,” explains doctoral student Nahum M. Gabinet from University of Haifa’s Department of Natural Resource Management.

But by 1950, 30% of the global population were living in urban areas, prompting growth and development. Fast forward nearly 70 years later and more than half the population (around 55%) have now taken up residence in the urban environment. With this influx of people came additional modes of mobility and a greater demand for goods and services, thereby accelerating economic development and intensifying motor traffic, construction, and the widespread use of sound and light-emitting electronic devices. Between sprawling urbanization and more sophisticated technology, humans have become more exposed to noise and artificial light at night (ALAN).

As if a global pandemic and a deteriorating climate weren’t enough, to what degree is noise and light pollution affecting our lives?

Presented at the 49th Annual Conference for Science and the Environment, a new Israeli study led by Gabinet and Prof. Boris A. Portnov illustrates and explores the connection between the quality and duration of sleep and the surrounding noise and light conditions of the built environment based on nationwide survey results from Israel in 2017.

Eyes and Ears

Between sprawling urbanization and more sophisticated technology, humans have become more exposed to noise and artificial light at night (ALAN). Photo by Luke Stackpoole on Unsplash.

Alongside modernization trends, industry development, and technological advancement, the last 250 years have been characterized by a continuous increase in noise pollution and light pollution.

Noise pollution refers to the constant elevated sound levels originating from machines and transportation and being routinely exposed to noises exceeding 85 decibels (dB) could yield health complications beyond sleep loss like hypertension, hearing loss and even heart disease. For comparison, a typical face-to-face conversation fluctuates anywhere from 50 dB to 65 dB, collective noise from rush hour traffic peaks at 80 dB, and construction noises tend to clock in around 110 dB. However, noise levels do not need to be this high to disrupt one’s sleep.

“According to studies, road noise at 42 dB or higher can alter the normal sleep cycle,” Gabinet points out.

Light pollution, on the other hand, refers to the overexposure to excessive artificial lighting, which not only accounts for a quarter of all electricity consumption worldwide, but can degrade eyesight and interfere with sleep patterns. Prolonged exposure to noise and light is not just affecting people either; it’s also disrupting ecosystems and negatively affecting the feeding habits, migratory routes, and reproductive patterns of both land and marine-based wildlife. 

Seeing as how 68% of the population is projected to be living in cities by 2050, the rate of urban expansion is showing zero signs of slowing down. Therefore, it is likely that overabundant noise and light from urban and economic development will continue to have an adverse effect on our health as well as the natural environment.

“There is a direct link between exposure to light, especially light on the blue spectrum, and the suppression of melatonin secretion, also known as the sleep hormone,” Gabinet explains. Melatonin is a hormone the brain secretes to ease one into sleeping. In doing so, it helps facilitate the timing of one’s circadian rhythm, the body’s 24-hour internal clock. However nighttime exposure to light can prevent melatonin from being produced, and thus complicate sleep patterns.

“There is a connection between melatonin and the eye,” says Gabinet. “Exposure to light disrupts its secretion and the biological clock mechanism. Therefore, the sleep process is impaired in its absence.”

Can’t Sleep?

The last 250 years have been characterized by a continuous increase in noise pollution and light pollution. Photo by Megan te Boekhorst on Unsplash

The researchers collected data procured by the Central Bureau of Statistics’ ongoing Social Survey of Israel (SSI) to assess the socio-economic status, health, and lifestyle attributes among those living in different localities throughout the country. These include questions regarding the duration and difficulties one has when it comes to sleep. The SSI data was then analyzed against ALAN satellite images of Israel and several road traffic noise metrics to determine whether the link between noise and light exposure and sleep deprivation was indeed significant.

According to the results of the study, the average sleep duration dropped by 18 minutes (4.5%) in the areas where residential road density averaged 5 km of road/km² compared to areas with 1 km of road/km². The frequency of reported sleep difficulties was also 3.5% higher in the areas with higher average road density. As well, the average sleep duration of those living in areas subject to greater exposure to nighttime artificial light were found to be 12 minutes shorter and caused reports of sleep difficulties to rise by more than 11%. 

In addition, the study revealed that the degree of light pollution is dependent on the level of noise pollution in the environment. In areas where noise pollution was low, light pollution’s effect on average sleep hours was minimal. But in the areas where noise pollution was high, light pollution was more intense and thus reduced average sleep hours by 4.5%.

More Harmful Than You Think

Interruptions to the duration and quality of our sleep directly affects our mental and physical health.

“Melatonin has an anti-inflammatory effect, so disruption of its secretion may impair the function of the immune system and increase the chance of cancer,” Gabinet explains.

“Noise while sleeping can cause headaches, fatigue, depression, cognitive decline, disruption of sleep cycles, secretion of cortisol (a stress hormone), and an increased risk of ischemic heart disease,” he continues.

“Our sleep hygiene––the habits designed to facilitate optimal sleep––are of paramount importance in regulating our emotions, assimilating our memories, learning, healing, and secreting growth hormones. Losing sleep increases the chances of diabetes, obesity, coronary heart disease, cancer and even death.”

Turn the Lights Down

Interruptions to the duration and quality of our sleep directly affects our mental and physical health. Photo by Kelly Sikkema on Unsplash.

Despite their permeating abundance, it is important to understand that we are not destined to be affected by consistent noise and light pollution forever. It is possible to change this part of reality and improve our quality of sleep by proxy.

“Regulatory moves are needed to set standards exposure limits for people trying to sleep in their homes,” says Gabinet. “A possible way to prevent light pollution is to require the use of appropriate technologies, such as smart street lighting, which eliminates any unnecessary light pollution.”

However, this is not the first time the issue of light pollution was brought under scrutiny. In 2016, a committee of experts arranged by the Israel Society of Ecology and Environmental Sciences (ISEES) recommended a series of actions to reduce and prevent light pollution. But in order to implement regulatory action to minimize it, it had to be recognized by the Ministry of Environmental Protection and the Ministry of Health as an environmental hazard. In fact, the report advised the government to reduce the use of white light in the 440-480 nanometer range (blue light) at night to reduce its negative impact on people and the environment.

With regard to noise, Gabinet suggested it would be possible to prevent noise pollution if the authorities promoted green and acoustic construction.

“New homes can be built with insulated walls, which makes it possible to block noise coming from the street as well as reduce the use of air conditioning and heating to improve energy efficiency.”

“We have to recognize that noise and light are polluting factors,” says Gabinet. “While they enable us to better control our lives, quickly move from place to place, and so on, they also carry with them a significant health risk. But, if we work to reduce overexposure to noise and light, we can have a better and healthier life.”

This ZAVIT Article was also published in the Jewish Journal on 25 Aug. 2021