We have become so attuned to the din around us that we can seldom make out the difference between harmful noise and plain loud noise. Noise is a major contributor to hearing loss, and the biggest disability among the people in the world, according to an Indian study. With technology taking over, we have lost the peace and quiet our previous generations enjoyed. The surround sound of a movie or the voice of a colleague screaming into her cell phone are everyday affairs. But both these can hurt your ears. Noise has become dangerous and it affects our wellbeing.
Our ear is divided into three parts—outer, middle and inner ear. The outer ear takes up sound and transfers it to the middle ear where the ear drum and three tiny bones amplify and carry it to the inner ear, which is a coiled up structure, called cochlea. The cochlea contains hair cells which are responsible for creating nerve impulses that carry sound to the brain, which registers it and causes hearing. If our hair cells are over-stimulated with loud sounds frequently or with a very loud blast for short periods, they get worn out and our hearing suffers. Unfortunately, hair cells are irreplaceable. So, noise-induced hearing loss can cause irreversible damage to our ears.
Noise intensity is measured in decibel [dB] units. We start perceiving noises at 0dB and hear them safely till 80dB. Beyond that, noise becomes dangerous. Besides the intensity, it is also the duration for which you are exposed to noise that matters. So, while it may take you days of exposure to the idling sound of a bulldozer at 85dB to get affected, just listening to your earphone at its highest volume can affect you adversely in just half an hour. Your inbuilt susceptibility to noise may also make a difference to how quickly noise harms you. While your friend may be able to dance unaffected in a discotheque for hours, you may want to leave in just a few minutes because of the volume. A 45db sound can make sleeping difficult, while a 120dB noise can cause ear pain. Incidentally, noise affects more than your ears.
High levels of noise can affect your health and wellbeing in more ways than one. Hearing loss can lead to irritability owing to a difficulty in understanding conversations or appreciating music. An exposure to very loud noise may be followed by ringing in the ears, called tinnitus. Some people may also experience anxiety, a surge of hormonal activity, an increase in pulse rate and blood pressure. The respiratory and digestive systems may also be affected. All of this could happen with just a single exposure to a loud burst of noise. If these exposures are frequent, your physiological disturbances may become chronic. Most importantly, noise can cause stress in daily life. Not being able to listen to normal sounds may affect your efficiency and may irritate others. Using a hearing aid may affect your self confidence. If you are pregnant, it may affect your unborn child.
Hearing loss from noise is a slow and painless process. You may have a disability before you notice it. In fact, sometimes it takes years for people to find it. "If you need to raise your voice for talking to someone who is just 3ft away, or if you are the only one missing out parts of conversation in a group because they sound muffled, you could be suffering from a hearing loss," says Dr Mani Bansal, speech-language pathologist and audiologist, visiting consultant, Max Superspeciality Hospital, Delhi. Your inability to carry on a normal conversation due to excessive background noise may also be an indication. If your family members complain that you raise the volume of your TV to hear, get yourself checked.
"A constant ringing or a blocked sensation in your ear after an exposure to loud sound warrants a consultation with an audiologist," says Dr Mani. More often than not, the reason could be a Temporary Threshold Shift, a temporary hearing loss, which rectifies itself in 2 – 3 days. But it is only your audiologist who can confirm that. "If your work involves constant exposure to loud sounds, you need half-yearly check-ups; even if it doesn't, a yearly check-up is recommended," she adds.
Prevention is care
It takes a few exposures to extremely loud blasts of sound to wear out the hair cells of your cochlea. But once they are gone, no amount of exercise or medication can recuperate them. "You may experience difficulty in hearing high frequency or shrill sounds and may also require a hearing aid, but wearing protective devices like ear plugs, advised by your audiologist may help prevent further damage," says Dr Mani. However, the good news is that noise-induced hearing loss is preventable and it doesn't take much to get into good habits that can protect your ears.
- Take a five-minute break every 15 minutes if you are in a noisy show.
- Avoid being close to a loud speaker at function.
- Keep the ringing volume of your phone low and don't talk too loudly on your cell-phone.
- Do not listen to music on earphones for over an hour at a stretch. Also, keep the volume as low as 50 per cent of the maximum limit. In fact, you should be able to hear what the person sitting next to you is saying.
- "Use thick curtains and carpets, rubber outlines on walls and walls constructed at correct angles which can help in absorption of ambient noise," says Dr Mani. Ideally, your living space should have acoustics adjusted to minimise ambient noise and to improve speech audibility.
- Avoid honking unnecessarily while driving.
- Do not use your cell phone at a stretch for more than 60 minutes, says an American research.
- Do not turn up the music to cover up ambient noise, it doesn't provide a respite.
- Avoid the use of loud and noisy fire-crackers. They cause instant damage to the ears.
- Keep the music in your car at low volume. It is better to listen to soft, soothing music on a CD/audio cassette rather than the radio, which proffers disturbed signals, bringing down the quality of sound and making you reach for the volume button again and again.
- "Wear ear plugs or ear muffs whenever you feel you are exposed to loud noise in a discotheque, pub, movie theatre or even in a gym," suggests Dr Mani. These help bring down noise levels by 40dB to 50dB. You can get your hearing protection from your audiologist.
- Get your automobiles serviced regularly to reduce noise levels.
The Government of India has laid down rules to bring down noise pollution in the country. Urge everyone to follow them.
With the International Noise Awareness Day being celebrated on 29th April, we have reason to change our habits and contribute actively in noise reduction with a little more vigour.
Things adding to the daily din
- The constant ringing of the phone.
- The noise caused by your television or radio.
- Loud music being played by your neighbour or at a nearby event.
- Constant blaring of devotional music from a neighbourhood temple, especially during festivals.
- Enthusiastic election contestants shouting slogans on megaphones and loudspeakers.
- Construction work happening at your workplace or a nearby building.
- A car alarm ringing at night.
- Generators in the marketplace.
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