Your ears pick up sound, but your brain decides how loud it seems, and the hearing system has a kind of volume knob that it turns up when less sound is coming in.

That is why nearly everyone hears a faint ring or hum in a truly silent room. In one classic study, 94% of 80 people with normal hearing heard sounds in a soundproof booth.

Most of the time your brain files that hum as background and you never notice it. Noise damage, age and hearing loss make the signal stronger and harder to file away.

Stress changes the filing step. Under pressure the brain’s alarm system scans for anything new, and a sound with no source outside you can get tagged as a threat.

Once it is tagged, the same ringing seems louder and more upsetting. In an app study of 658 people, stress in the moment helped explain why loud days felt so much worse.

Muscles matter too. Most people with tinnitus can change its pitch or volume by tensing the jaw or neck, because those nerves feed into the same hearing pathways.

Sleep adds a third layer. Poor sleepers in a Swedish study of nearly 10,000 workers reported ringing about twice as often as people who slept well.

That is the loop worth breaking: stress sharpens attention and tightens muscles, the ringing gets louder, and the worry it brings keeps the whole system on alert.

The inner ear turns sound into nerve signals, and the brain decides how much to boost them. When less sound comes in, from noise damage or age, the brain turns its own gain up to make up for it. Researchers call this central gain, and much of the detail comes from animal research.

Turning the gain up has a side effect, because the quiet background chatter of the hearing nerves gets boosted too, and it can come through as a ring, hiss or hum that has no source outside your head.

You can hear this for yourself, since in a 1953 study 94% of 80 adults with normal hearing heard sounds after a few minutes in a soundproof room. A repeat study in 2008 found the same in 83% of 53 young adults.

So the sound itself is common and mostly harmless, and what decides whether it becomes a problem is how much attention your brain gives it, and that is the part stress can change. It is also why the ringing so often seems worst at bedtime, when the room goes quiet and there is nothing else for your brain to listen to.

Stress works through two routes. The fast one is the nervous system, which sharpens attention and readies the body within seconds. The slow one is hormones, which build over minutes and can linger for hours.

A small lab study tested a purely mental stressor. Eighteen people with tinnitus and eighteen without gave a speech and did mental arithmetic in front of judges. Those with tinnitus had a flatter stress hormone rise, not a bigger one.

A larger study of 348 adults used a mixed task: a hand in cold water, a tricky colour-word test and being filmed. Afterwards, women with high levels of exhaustion found loud sounds uncomfortable at lower volumes than women with low exhaustion did.

Put together, stress seems to change how the hearing system is tuned rather than simply pumping out more hormone. The exact wiring is still being worked out, and both studies are small enough that the finer points should be treated as open.

You do not need a crisis for this to matter. In a survey of nearly 10,000 Swedish workers, hearing problems rose step by step with burnout and long-term stress scores, rather than jumping only at the extreme end.

Sleep showed the clearest steps. About 19% of people who slept very well reported ringing, rising through each band to 39% of people who slept very badly.

Stress seems to matter most for how bothersome the ringing gets. A Swedish survey of 12,166 people found noise and stress both linked to tinnitus, and stress was especially important in mild ringing becoming severe.

Daily tracking points the same way. Among 658 app users, the same loudness felt more distressing at stressed moments, so a normal day can feel very different from a tense one with no change in your ears. The sound can stay the same while the bother it causes goes up and down with your stress.

Stress is rarely the only cause, and it is worth knowing the others. In the national US survey, people with regular loud noise at work reported tinnitus about three times as often. Loud music, gigs and headphones count too.

Age plays a big part: across 113 studies, about 10% of adults under 45 had tinnitus, compared with nearly 24% of people 65 and over, mostly because hearing slowly changes with age.

Posture and tension feed in as well, because about 80% of people with ongoing ringing could change it by tensing their head and neck, so long hours hunched at a screen with a clenched jaw can turn it up.

Coffee is less guilty than most people think. In 65,085 women followed for 18 years, more caffeine went with less new tinnitus, and quitting coffee did nothing for it in a trial of 66 people. Some medicines can trigger ringing, so check with a pharmacist.

The loop is mostly about attention. The more you listen for the sound, check it and fear it, the more the brain treats it as important, and the harder it becomes to tune out.

The encouraging part is that this loop is changeable. Pooling 28 trials and 2,733 people, talking therapy that targets these thoughts and habits seemed to lower how much tinnitus affected daily life.

In a trial of 75 people, both mindfulness and relaxation training reduced how loud and severe their tinnitus felt, with mindfulness helping more. The gains lasted at least six months.

Mood moves with it. In a two-year study of Swedish workers, people whose low mood lifted also saw their tinnitus become less severe, which suggests the load can shift as life gets easier.

One belief deserves retiring: that the ringing is a noise made inside a damaged ear. For most people, it is the brain’s hearing system turning up its own volume. The ear may have started it, but the brain keeps it going.

The stress evidence also has gaps. A review of 50 studies found many people report louder tinnitus when stressed, but not all of them link stress to it, and results before and after treatment were inconsistent.

The hormone story is not tidy either. In the lab study, people with tinnitus had a flatter stress hormone response than others, and their ringing did not seem to get louder during the stressful task itself.

So hold the promise loosely. Calming the system clearly helps many people cope, and the trials mostly measured how much the ringing bothers you rather than whether it goes away. Long-term evidence is still thin.