You came home from a concert or a busy shift, your ears were ringing, and by the morning the ringing was mostly gone. Your watch pushed a notification at some point that you swiped away.
That notification is one of the more interesting things your wearable does, and almost nobody looks at it. Apple Watch has been sampling the sound around you continuously since watchOS 6 — traffic, machinery, a bar, the gym, your own headphones — and writing it into the Health app as a long-term record of what your ears have been exposed to.
It is worth paying attention to, and not only for the obvious reason. Hearing is one of those systems where the damage accumulates silently for decades and then presents as a problem in your sixties. It is also, according to the dementia prevention literature, one of the most consequential — and most fixable — risk factors for cognitive decline that we know of.
This is what the numbers mean, what they are actually telling you, and what to do about it.
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TL;DR: Your Apple Watch measures environmental sound levels automatically and records headphone volume in the Health app, but you have to go and look. Big picture: 10 percent of Apple Hearing Study participants had a diagnosed hearing loss, 20 percent failed a hearing test against WHO standards, and 25 percent had a daily average sound exposure above the WHO's recommended limit. Long-term noise exposure is linked to permanent hearing loss, sleep disruption, raised blood pressure, and cardiovascular risk, and hearing loss is one of the largest potentially modifiable risk factors for dementia — the 2020 Lancet Commission estimated roughly 8 percent of dementia risk. The practical fixes are unglamorous: turn the volume down, use noise cancellation so you can listen quieter, stand away from the speakers, take quiet breaks, and check your 7-day headphone average once a week.
Your watch has been measuring sound all along
The Noise app on Apple Watch does not need to be opened. It samples environmental sound levels in the background while you wear the watch, and it works like a sound level meter: it reports the average level in decibels, A-weighted, which means it is filtered to roughly match how the human ear perceives loudness.
Two things trigger an alert:
- A loud environment notification when the average sound level reaches 90 dB over a 30-minute period.
- Health app classification of environments above 80 dB as loud when you review your data afterward.
Separately, if you wear AirPods or other headphones with volume tracking, your iPhone logs headphone audio levels and gives you a 7-day average, plus a weekly notification if you have been listening too loudly for too long.
That is it. No wearable on the market diagnoses hearing loss, and none of this replaces an audiologist. What it does do is give you a longitudinal record of exposure, which is precisely the thing you cannot reconstruct from memory. Nobody accurately remembers how loud last Tuesday was.
How loud is too loud
Decibels are logarithmic, so a 10 dB increase is roughly a doubling of perceived loudness — and ten times the acoustic energy. That is why the exposure limits fall so fast.
Typical levels:
- 30 dB — quiet room, whisper
- 60 dB — normal conversation
- 70 dB — busy café, city street
- 80 to 85 dB — heavy traffic, a blender, a loud restaurant
- 90 dB — motorcycle, lawnmower, busy nightclub at distance
- 100 dB — live music, a bar with a band, headphones at full volume
- 110 dB — front row at a concert, a club speaker stack
- 120 dB — siren at close range, an emergency
Exposure limits are about dose, not just level. The widely used occupational standard is 85 dB for 8 hours, with a 3 dB exchange rate: every 3 dB louder halves the safe duration. That gives you:
- 88 dB — 4 hours
- 91 dB — 2 hours
- 94 dB — 1 hour
- 100 dB — 15 minutes
- 110 dB — under 2 minutes
For recreational listening, the World Health Organization's safe-listening guidance is more conservative: a weekly "sound budget" of about 80 dB for a maximum of 40 hours per week for adults (75 dB for children). Most people who work in offices and listen to podcasts at a moderate volume are nowhere near it. Most people who go to a loud gym class every morning, commute with headphones at full volume, and take in a concert on Saturday are well over it — and have never once seen the number.
What loud sound actually does to your ear
Inside your cochlea there are roughly 16,000 hair cells that convert vibration into nerve signals. You are born with all of them, and they do not regenerate.
When sound is loud enough, those cells get damaged. The stereocilia — the tiny bundles on top of each hair cell — can be bent or sheared off. Sometimes they recover within a day or two, which is why the muffled hearing after a concert goes away. But repeated exposure causes hair cells to die, and the ones that handle high frequencies die first. That is why the earliest sign of noise damage is usually difficulty hearing conversation in a noisy room rather than any obvious hearing loss.
There is a second mechanism that is less visible. Even when the hair cells survive, loud sound can damage the connections between the hair cells and the auditory nerve — a condition sometimes called cochlear synaptopathy, or "hidden hearing loss". The audiogram looks normal, the person can hear sounds in a quiet room, but hearing in noise and sound processing in the brain are worse than the test suggests.
Practically, this gives you a rule worth remembering: ringing or muffled hearing after an event is not a normal side effect, it is a temporary threshold shift, and it means you spent past the limit. The ringing is a symptom, not a badge.
The dementia connection, which is the part people miss
This is where the topic stops being about ears and starts being about long-term brain health.
The 2020 Lancet Commission on dementia prevention, intervention, and care reviewed the modifiable risk factors for dementia and identified hearing loss as one of the largest — accounting for roughly 8 percent of population attributable risk, and one of the most important in midlife. The 2024 update kept hearing loss on the list. The same conclusions appear in the ear-and-brain literature, where age-related hearing loss is described as the single largest potentially modifiable risk factor.
The best-known longitudinal evidence comes from the Baltimore Longitudinal Study of Aging, which followed older adults for years and found that hearing loss was independently associated with a higher risk of developing dementia, with a dose-response effect: the worse the hearing, the higher the risk. Notably, that association held even after accounting for age, sex, education, diabetes, smoking, and hypertension.
There are a few plausible mechanisms, and they are not mutually exclusive:
- Cognitive load. When hearing is effortful, the brain spends working memory on decoding sound instead of on everything else.
- Social isolation. Missing parts of conversation makes social situations exhausting, and people withdraw. Isolation is itself a dementia risk factor.
- Reduced brain stimulation. Less auditory input may mean less activity in the regions that process it.
- Shared underlying causes. Vascular disease and inflammation may drive both, rather than one causing the other.
The genuinely useful part of this literature is that hearing loss is treatable, and treating it appears to help. The ACHIEVE randomised trial published in 2023 found that hearing intervention slowed cognitive decline in a subgroup of older adults at higher dementia risk. It is not a cure for anything, but it does mean that "I will deal with my hearing later" is a costly default.
Noise is also a cardiovascular and sleep problem
Even if your hearing is fine, chronic noise exposure does something to the rest of your body.
The WHO's environmental noise guidelines review the evidence and conclude that long-term exposure to traffic and aircraft noise is associated with increased risk of ischaemic heart disease, hypertension, and stroke — with the guidance that outdoor noise should be kept below roughly 53 dB Lden for road traffic and below 45 dB Lnight to protect sleep. Those are daytime and nighttime weighted averages, not peaks.
Two mechanisms do most of the work:
Sleep disruption. Noise that does not wake you still changes your sleep architecture. Nighttime noise increases arousals and shifts the autonomic balance toward sympathetic activity, which shows up as a higher overnight heart rate, more fragmented sleep, and less deep sleep. If you live near a busy road, a rail line, or an airport, this is a real and measurable effect that most people attribute to "sleeping badly".
Stress physiology. Noise is a stressor. Repeated exposure elevates stress hormones and blood pressure and keeps the nervous system in a low-grade activated state. If your HRV has been quietly drifting down for a month with no change in training or sleep, and you moved next to a construction site, that is worth connecting. There is more on this mechanism in our guide to what cortisol actually does to recovery.
Reading your own numbers this week
The data is already on your phone. Here is how to look at it.
Environmental sound levels (Health app, on iPhone, or Noise app on watch): you get a history of your daily average and how much of the day you spent in loud environments. If you see a block of time above 90 dB, that is your 30-minute alert. A single concert will not show up as a health problem. What matters is the pattern: if your average is high most days, your exposure is chronic, not incidental.
Headphone audio levels: this is the one people find genuinely surprising. The 7-day average, expressed as a reference level equivalent to the volume in a quiet environment, tells you whether your listening habit is loud. If you routinely push past 90 dB, you are doing meaningful dose, and the fix is usually not "listen less" but "use noise cancellation and let the environment be quieter".
The 80 dB category: if a large share of your day sits in the 80 to 90 dB band, look at where. Commute, gym, workshop, open-plan office, kitchen. Naming the source is what makes it fixable.
Trends, not days. Apple's Health app will show you the trend line. Judge that. One loud wedding does not matter. A daily 88 dB commute does.
What actually protects your ears
There is a short, boring, well-supported list here.
- Distance. Sound intensity drops by roughly 6 dB every time you double your distance from the source. Standing at the back instead of the front row is worth more than anything else you can do in a venue.
- Duration. Halve the time, and you halve the dose. Splitting a loud exposure into two shorter blocks with a quiet break in between is meaningfully better than one long block.
- Volume, and the 60/60 habit. If you listen on headphones, aim for around 60 percent of maximum volume for around 60 minutes at a time, with breaks. It is a crude rule, but it keeps most people under the WHO budget for recreational listening.
- Noise cancelling rather than louder. On a plane, a train, or in an open-plan office, cancellation lets you hear your podcast at a much lower volume. This is the single best use of the technology.
- Earplugs at concerts and loud events. Even the basic foam type cuts 20 to 30 dB. Musician's earplugs attenuate more evenly, so music still sounds like music. This is the cheapest permanent-protection decision available and almost nobody does it.
- Recovery time. Your ears need quiet hours after a loud dose, not another loud dose. A quiet evening after a loud day is not laziness, it is dose management.
- Protect sleep specifically. If you live somewhere loud, this is where spending money is genuinely justified: good window sealing, heavier curtains, or well-fitted earplugs or masking sound at night. Sleep is where the cardiovascular cost of noise accumulates fastest.
When to get your hearing checked
The Apple Hearing Study found that around half of participants had not had a hearing test in 10 years or more. If you are in that group, here is the honest test of whether you should care:
- You struggle to follow conversation in a restaurant or a car with background noise
- People tell you the TV is too loud
- You often ask people to repeat themselves, especially women's and children's voices
- You get ringing or buzzing in quiet rooms — tinnitus, which the Apple Hearing Study found affected about 78 percent of participants at some point
- You work, or have worked, somewhere consistently loud
If any of those apply, get a proper hearing test. Many countries have free or low-cost options, and new iPhone and AirPods hearing features have also made basic screening much more accessible — useful as a first signal, not as a replacement for an audiologist, who can test the frequencies and speech-in-noise performance that a screening misses.
The reason to act earlier rather than later is the same reason the dementia literature is interesting: the intervention works best before the brain has spent 15 years compensating for missing signal. And the reason the topic sits in a longevity conversation at all is that hearing, sleep, blood pressure, and cognitive function are not separate systems.
Quick checklist for a quieter week
- Open the Health app and look at your 7-day headphone average and environmental sound levels
- Identify your loudest recurring block of the day and name the source
- Turn headphone volume down and noise cancellation on
- Take earplugs to the next loud event, and stand further back
- Get one quiet hour after any loud exposure
- Treat post-event ringing as a signal, not a coincidence
- Get a hearing test if it has been more than a few years, or if any signs above apply
Your watch is already collecting this. It takes about two minutes to read it, and the lesson it teaches — that long-term exposures matter far more than single events — is the same one that shows up everywhere else in your recovery data.
Century AI helps you understand your body with a daily health score, recovery score, and sleep insights — using the watch you already wear. If you want to go deeper on the long-term markers that matter, read our guide to biological age and the metrics that track it, or our breakdown of what cortisol does to recovery.