Living in a noisy neighborhood increases the risk of developing dementia

 “Noise is no good, good makes no noise”, said the Frenchman Vincent de Paul. Living in big cities and working in noisy offices or factories, we forget the sound of silence as we immerse ourselves more and more in the noise, which becomes the soundtrack of our life. However, our brains need silence. Science warns us that noise can have very negative effects.

Noise, the modern plague that affects our brain

Some American researchers have called noise "the modern plague". They indicate that “environmental noise pollution is a threat to health and well-being. It is more severe and widespread than ever and will continue to increase in intensity and severity due to population growth, urbanization and the use of increasingly powerful, varied and highly mobile noise sources. It will also continue to grow thanks to the sustained growth in air, rail and road traffic, which continue to be the main sources of environmental noise ”.

They also report that "the possible health effects of noise pollution are numerous, widespread, persistent and of medical and social importance". They conclude that “noise produces direct and cumulative negative effects that damage health”.

Now, researchers at the University of Michigan have taken it one step further by discovering that the noise we are exposed to during our lifetime could trigger dementia in old age. 5,227 people over the age of 65 were analyzed, who had cognitive assessments every three years, as well as checking the noise level they were subjected to in their neighborhood.

It was found that a 10 decibel increase in ambient noise corresponds to a 29-36% increase in the likelihood of developing cognitive impairment. "These findings suggest that noise can affect cognition in old age and the risk of dementia," they conclude.

It should be noted that “ a harmful noise level can be exposure to more than 85 decibels (dB) for eight hours or 100 dB for 15 minutes” , according to the WHO. To get an idea, just know that in a traffic jam we are exposed to an average of 90 dB while a drill or a horn generates 120 dB.

The neurotoxicity of noise

Previous research had already warned about the dangers of noise to our brains. A study conducted at Cornell University revealed that constant noise from airplanes can cause an increase in blood pressure and stress levels in children living in areas under airport routes, as well as causing a deficit in language acquisition.

In 1975, researchers from New York University analyzed children who attended a school located near an elevated railroad. Half of the students who participated in the research were in classrooms facing the platforms and the other half in classrooms at the rear of the school, a quieter area. Students on the quieter side performed better on reading tests, and in the sixth grade they were one point ahead of students in the noisier classrooms.

Noise neurotoxicity could also affect adults, accelerating cognitive decline and dementia due to the effects of inflammatory processes. In animal experiments, noise was found to cause neuropathological changes indicative of dementia. In mice, for example, exposure to noise promotes the production of beta amyloid in the hippocampal tissue, which is precisely the cause of dementia.

Processes of oxidative stress, inflammation, degenerative changes in synapses and lower frequency of neuronal activation were also observed. Furthermore, animals exposed to noise show a decrease in their learning and memory capacity.

In addition to the neuropathological consequences, scientists believe that the vascular effects of noise may also trigger dementia processes as they have been linked to an increase in heart rate, peripheral vasoconstriction and increased risk of hypertension. All risk factors for dementia.

The main problem is that noise prevents our brain from resting, keeping it constantly alert, profoundly affecting the quality of sleep.

In fact, if we are continuously exposed to noise, our brain is constantly busy processing the incoming information. Our mind is exposed to a continuous stream of external stimuli that prevent essential rest.

When we cannot sleep well, because sleep is not restful and we wake up all the time, our brain is unable to eliminate waste substances from its metabolism. That's why sleep problems have been linked to the onset of different types of dementia.

Enjoy the silence

The silence of the mind is a necessity , although in the modern world has become a luxury. Therefore, the first step to living in a quieter environment is to make sure you are not contributing to noise pollution. The second step is to look for areas of silence that allow us to access a calmer environment where we leave behind irritability, frustration, stress and confusion.

We can leave the city to enjoy the silence surrounded by nature, which also involves turning off the mobile phone. It is about learning to be, without speaking, letting the therapeutic silence reach every fiber of our body, so that our brain can regenerate.

Sources:

Weuve, J. et. Al. (2020) Long ‐ term community noise exposure in relation to dementia, cognition, and cognitive decline in older adults. Alzheimer & Dementia ; DOI: 10.1002 / raised 12191.

Cui, B. et. Al. (2015) Chronic Noise Exposure Acts Cumulatively to Exacerbate Alzheimer's Disease-Like Amyloid-β Pathology and Neuroinflammation in the Rat Hippocampus. Nature Scientific Reports ; 5: 12943.

Basner, M. et Al. (2014) Auditory and non-auditory effects of noise on health; Lancet ; 383 (9925): 1325-1332.

Evans, GW & Maxwell, L. (1997) Chronic Noise Exposure and Reading Deficits: The Mediating Effects of Language Acquisition. Environment and Behavior ; 29 (5), 638–656.

Bronzaft, AL & McCarthy, DP (1975) The Effect of Elevated Train Noise On Reading Ability. Environment and Behavior ; 7 (4): 517-528.