The sound of the siren is one of the most important means of saving lives in an emergency. It is intended to trigger an immediate response and lead the public to a protected space. However, alongside its critical role, it turns out that the high sound intensity may also have an effect on the hearing system.
Sirens can reach intensities of up to 120 decibels, a level significantly higher than the threshold considered safe for prolonged exposure. According to the World Health Organization, repeated exposure to noise above 85 decibels may over time cause damage to hearing.
The hearing system is based on a particularly delicate structure in the inner ear called the cochlea. Inside the cochlea are tiny hair cells whose role is to convert sound waves into neural signals that are transmitted to the brain.
When these cells are exposed to particularly loud noise or to repeated noise over time, they may be damaged. Unlike other cells in the body, hair cells do not regenerate, and therefore the damage may be permanent.
Such damage is called noise-induced hearing loss.
The damage that is not always seen in tests
Hearing damage can occur in two main ways. The first is a one-time exposure to particularly loud noise, a condition known as acoustic trauma. The second is repeated exposure to loud noise over time.
Even if each siren lasts a short time, the cumulative exposure over months may cause gradual damage. Sometimes a person does not notice it immediately. The first signs may appear only after a prolonged period.
In recent years, another condition has been described called hidden hearing loss. In this condition, standard hearing tests may appear normal, but the person has difficulty understanding speech, especially in a noisy environment.
The reason for this is damage to the connections between the hair cells and the auditory nerve, and not necessarily to the cells themselves. Therefore, it is important to be attentive to symptoms even when basic tests do not indicate a problem.
The signs to pay attention to
The two most common phenomena after exposure to loud noise are tinnitus and hyperacusis.
Tinnitus: Manifests as hearing ringing, buzzing or whistling without an external source. Sometimes this is a temporary phenomenon, but in some cases it can last a long time.
Hyperacusis: Increased sensitivity to ordinary sounds. People who suffer from it may experience discomfort even from everyday sounds and avoid noisy environments.
Beyond the direct effect on the ear, sirens also activate the body’s stress system. The loud sound triggers an emergency response that includes the release of hormones such as adrenaline and cortisol.
Prolonged exposure to such a state may also affect the way the brain processes sounds and increase sensitivity to noise.
Scientific knowledge in this field is still developing, but it is already clear that the civilian population may also be affected by repeated exposure to loud noise. Certain groups are at higher risk, including children, the elderly and people with existing hearing problems.
When to seek testing
If symptoms such as ringing in the ears, difficulty understanding speech or sensitivity to noise appear, it is recommended to seek an examination with an ear, nose and throat doctor or to undergo a hearing test. Early diagnosis can help cope with the problem and prevent worsening.
The bottom line, sirens save lives, but repeated exposure to loud noise is not without effect. Awareness of symptoms and maintaining hearing health can help identify problems in time and preserve quality of life even during challenging periods.
The author, Dr. Ameen Biadsee, ENT coordinator in the Sharon Shomron district at Clalit, a specialist from the endoscopic sinus surgery unit at Meir Hospital and a senior lecturer in the Department of ENT Medicine at Tel Aviv University