How does noise, the "big devil" of sound, break people's defenses?

Have you ever been disturbed by noise? For example, the rhythmic music of square dancers, the sound of electric drills during renovations, the noisy noise of the naughty children next door, the sound of high heels hitting the ground upstairs... As the pace of life accelerates, noise has filled every corner of our lives, and noise pollution has become a problem that cannot be ignored.

The harm of noise

Have you ever thought that the "fat belly" on your belly might be caused by hearing? A foreign study found that residents who are exposed to noise for a long time are more likely to develop abdominal obesity, also known as a pear-shaped body, than those who live in a quiet environment. This is because noise affects the body's hormone levels, calorie intake, and sleep quality, which can lead to weight gain.

Generally speaking, even beautiful music can become annoying noise when it is not needed. Noise pollution not only makes people irritable and causes poor sleep, but also directly affects the central nervous system, causing sympathetic nerve tension, faster heartbeat, irregular heartbeat, higher blood pressure, etc. It can also cause or trigger diseases such as heart disease, learning disabilities and tinnitus, thus shortening people's lifespan.

Experiments show that noise levels of 40 to 50 decibels can damage hearing, noise levels of 65 to 75 decibels can affect heart disease and blood pressure, noise levels of 80 to 85 decibels can cause mild hearing damage, and long-term exposure to noise levels above 85 decibels can cause a small amount of noise-induced hearing loss.

According to relevant standards in my country, the noise level in residential areas should not be higher than 55 decibels during the day and lower than 45 decibels at night. However, some noises with low decibels are not easy to detect, spread farther, and have a strong ability to cross obstacles, and can even be transmitted through buildings. Most importantly, low-frequency noise is closer to the resonance frequency of human organs, which can easily cause sympathetic nerve tension, continuous stress response, tachycardia and high blood pressure. Being in a low-frequency noise environment for a long time is a chronic injury to the human body, which can easily cause neurological diseases, cardiovascular diseases, mental and psychological diseases, digestive diseases, and other serious diseases.

How does noise damage hearing?

The human inner ear cochlea contains sensory nerve cells - auditory hair cells, which can help us hear sounds. Short-term exposure to a noisy environment can fatigue the auditory hair cells, causing temporary hearing loss or tinnitus. After leaving the noisy environment, hearing usually improves. However, long-term exposure to a noisy environment may permanently damage the auditory hair cells and other structures of the inner ear, leading to irreversible hearing loss, known as noise-induced hearing loss or noise-induced deafness. At first, you may just not be able to hear some high-pitched sounds, such as birdsong or bells. As hearing damage progresses, it may be difficult to communicate with others, especially in noisy places such as restaurants.

Noise-induced hearing loss is often ignored in the early stages. By the time patients realize it, they may have difficulty hearing others speak clearly. At the same time, the hearing loss of this group of people is much faster than that of normal people. When hearing loss reaches a certain level, the effect of using hearing aids will be greatly reduced. It is easy to "hear" but "not understand", which seriously affects the social interaction and quality of life of the hearing-impaired.