Explainers
Volume and hearing health: listening at length without damaging your ears
Hearing loss caused by noise is permanent: the cells of the inner ear do not regenerate. The good news is that it is entirely preventable, provided you understand that the risk depends on two things at once: the sound level and the duration.
How noise damages the ear
Deep in the inner ear, in the cochlea, about 15,000 hair cells convert vibrations into nerve signals. A sound that is too loud or goes on for too long exhausts them, then destroys them. In humans, they do not grow back: every cell lost is lost for life.
The damage begins with the high frequencies and goes unnoticed for a long time, because everyday conversation remains intelligible. The first signs are difficulty following a discussion in a noisy place, then tinnitus, that ringing or buzzing with no external source. Ringing ears or a muffled sound after a listening session are a warning: the dose was too high.
Decibels: a deceptive scale
Sound level is measured in decibels (dB), on a logarithmic scale. Two reference points are enough:
- +3 dB: the sound energy received by the ear doubles. The difference is barely audible.
- +10 dB: the energy is multiplied by ten, and the perceived volume roughly doubles.
In other words, what seems “a bit louder” in fact carries far more energy. That is the whole trap of the volume button.
| Situation | Approximate level |
|---|---|
| Normal conversation | 60 dB |
| Busy street, inside a car | 70 – 80 dB |
| Tube, aircraft cabin | 80 – 95 dB |
| Music player or phone at maximum volume | 95 – 105 dB |
| Concert, nightclub | 100 – 110 dB |
The dose: level and duration
The risk depends on the total energy received, as with exposure to the sun. The World Health Organization and the International Telecommunication Union have set a reference in their joint standard on personal audio devices (ITU-T H.870): for an adult, 80 dB for 40 hours a week.
The 3 dB rule gives the rest: each time the level rises by 3 dB, the safe duration is halved.
At 89 dB, a common level on public transport with poorly isolating earbuds, the weekly dose is reached in 5 hours: one week of commuting. At 98 dB, less than 40 minutes is enough.
Occupational health rules follow the same logic: the American institute NIOSH recommends not exceeding 85 dB over an 8-hour day, with the same halving for every 3 dB.
Six habits that protect you
- Block out noise rather than drowning it out. On a Tube train at 90 dB, you have to push the music beyond that to hear it. With active noise cancelling or good isolation, you can listen comfortably at 70 dB. This is the most effective measure of all.
- Stay below 60% of the volume in everyday use. It is a rough guide, because devices are not all calibrated in the same way, but it keeps most combinations under 85 dB.
- Take breaks. Ten minutes of quiet every hour lets the hair cells recover.
- Use the exposure tracking on your phone. iOS and Android measure the level sent to the headphones and warn you when the weekly dose is exceeded.
- Test yourself. If someone a metre away has to raise their voice for you to hear them, it is too loud.
- Protect yourself away from headphones too. Concerts, DIY and motorbikes count towards the same weekly dose. Filtered earplugs attenuate without distorting the music.
Children: a lower limit
Children's ears are no more fragile for the same energy, but they have a lifetime of exposure ahead of them and are poor at noticing discomfort. The WHO-ITU reference for sensitive people, children included, is 75 dB for 40 hours a week.
Children's headphones generally limit the volume to 85 dB. That is useful, but it is no guarantee: at 85 dB, a child's weekly dose is reached in about 4 hours. Volume-limited headphones therefore do not remove the need to limit listening time as well. Three precautions:
- check that the limit cannot be switched off with a simple button the child can reach;
- favour a model that isolates a little, so that the child is not tempted to turn the volume up in the car or on a plane;
- be wary of the cable: on some models, the limit applies only over Bluetooth.
The kids' headphones buying guide details the models and their real limits.
Sleeping with earbuds
At night, the volume needed is low, but the duration is long. Masking noise at 40 or 50 dB poses no problem for your hearing. The precautions lie elsewhere: choose earbuds designed for sleep, which do not press on the ear canal when you lie on your side, clean the tips, and set a sleep timer if you are listening to anything other than background noise. See sleep earbuds.
When to seek help. Tinnitus that lasts more than 24 hours, a sudden drop in hearing in one ear or a persistent blocked-ear sensation warrants a prompt appointment with an ENT doctor. Some sudden hearing losses can be treated, provided you act within the first few days. This guide offers general pointers and is no substitute for medical advice.
Sources and references
- World Health Organization — Deafness and hearing loss: safe listening
- ITU-T H.870 — Guidelines for safe listening devices/systems (WHO-ITU standard)
- NIOSH (CDC) — Noise and occupational hearing loss
- EN 50332 — Sound system equipment: headphones and earphones associated with personal music players, maximum sound pressure level
Frequently Asked Questions
At how many decibels do headphones become dangerous?
There is no single threshold: the risk depends on level and duration. The WHO and ITU reference is 80 dB for 40 hours a week for an adult. At 89 dB, that dose is reached in 5 hours; at 98 dB, in less than 40 minutes.
Are headphones limited to 85 dB safe for a child?
They are safer than unlimited headphones, but not without a limit on listening time. The WHO-ITU reference for children is 75 dB for 40 hours a week. At 85 dB, that dose is reached in about 4 hours a week. So you need to limit listening time as well.
Does noise cancelling protect your hearing?
Indirectly, yes. By reducing ambient noise, it lets you listen to music at a markedly lower volume on public transport or in an open-plan office. It is not, however, a substitute for certified hearing protection against very loud noise such as machinery or a concert.