03What noise does to your ears, sleep and heart

The short version: Loud sound damages hearing through a mix of level and time: in the US, the federal research agency NIOSH recommends no more than 85 dBA averaged over 8 hours, and every 3 dB louder halves that time, so 100 dBA is a 15-minute dose. Quieter, long-term noise from traffic and aircraft is linked by WHO and the European Environment Agency to annoyance, broken sleep, heart disease and slower reading in children, mostly as population-wide statistics rather than individual verdicts. WHO's 2018 guidelines set outdoor targets by source, with the strictest night value for aircraft.

This section reports what NIOSH, OSHA, NIDCD, CDC, WHO and the EEA say. It is not medical advice. For your own hearing, sleep or heart, ask a doctor or audiologist and read the agency pages in the footnotes.

How loud is too loud for your ears?

What you hear: a lawn mower, a hand dryer, a club, a siren going past.

Hearing damage depends on how loud a sound is and how long you are in it. Workplace rules express this as a time-weighted average (TWA) - your exposure averaged over a shift, usually 8 hours - plus an exchange rate, the number of decibels that halves the allowed time.

The US has two numbers, and they disagree:

• NIOSH, the federal research agency, sets a Recommended Exposure Limit (REL) of 85 dBA as an 8-hour TWA with a 3 dB exchange rate: each 3 dBA increase halves the allowable time.²¹ This is advice, not law. NIOSH recommends hearing protection whenever noise is above 85 dBA regardless of how long, and notes that about 8% of workers could still develop hearing loss at 85 dBA.³ ACGIH uses the same 85 dBA and 3 dB.²⁶
• OSHA, the enforcement agency, sets a Permissible Exposure Limit (PEL) of 90 dBA as an 8-hour TWA with a 5 dB exchange rate. At 85 dBA TWA - its action level - general industry, maritime and longshoring employers must run a hearing conservation program; construction uses 90 dBA.²⁷ OSHA's impulsive or impact noise ceiling is 140 dB peak sound pressure level.²⁸

CDC estimates about 22 million US workers are exposed to potentially damaging noise each year.²⁷

A field test you can do without a meter: if you have to raise your voice to be heard by someone about 3 ft (1 m) away, the level is likely 85 dBA or more; if you have to shout, it is likely 95 dBA or more.²⁰

For everyday, non-work life, NIDCD says sounds at or below 70 dBA are unlikely to cause hearing loss even after long exposure.²² In 1974 the US EPA identified 70 dBA averaged over 24 hours (about 75 dBA over 8 hours) as protective of hearing, and 55 dBA outdoors and 45 dBA indoors to avoid speech interference and annoyance - and said these were not regulations.²⁹

How long can I listen at 100 decibels?

What you hear: a loud concert, headphones turned all the way up, a crowd at a big game.

At 100 dBA, NIOSH's recommended daily limit is 15 minutes; OSHA's legal limit is 2 hours.²⁹²⁸ NIDCD says damage is more likely after at least 14 minutes at 100 dBA and 2 minutes at 110 dBA.³⁰

Daily unprotected exposure, by agency. Values without "calc." are printed by the agency; "calc." values are our arithmetic using each agency's stated exchange rate (NIOSH 3 dB, OSHA 5 dB) and are not printed in the source tables.²⁹²⁸

Doses add up across the day: half an hour at 97 dBA uses a full NIOSH daily allowance. For sound systems and concert levels from the engineer's side, see The Show File.

How many people already have noise damage?

What you hear: nothing unusual - which is the point.

CDC's 2017 Vital Signs report, using 2011-2012 national hearing tests, found an audiometric notch - a dip in the hearing test typical of noise damage - in 24.4% of US adults aged 20 to 69, about 39.4 million people. Among adults with no loud work exposure, 19.9% had one, and so did 23.5% of people who rated their own hearing excellent or good.³ CDC's summary adds that about 53% of people with noise damage report no on-the-job exposure, and that hearing loss is the third most common chronic condition in the US.³¹

NIDCD frames the range more cautiously: at least 10 million (6%) and up to 40 million (24%) US adults under 70 (2011-2012 data), plus up to 17% of teens aged 12 to 19 (2005-2006 data), showing signs suggestive of noise-induced hearing loss (NIHL).²² NIDCD calls NIHL "the only type of hearing loss that is completely preventable."²²

WHO estimates 1.1 billion young people are at risk of hearing loss from unsafe listening, and that 40% of 12- to 35-year-olds in middle- and high-income countries are exposed to damaging levels at entertainment venues.³²

WHO's deafness and hearing loss fact sheet (updated 3 March 2026) puts the number of people worldwide who need rehabilitation for disabling hearing loss at 430 million, including 34 million children, and projects that nearly 2.5 billion people will have some degree of hearing loss by 2050, with more than 700 million needing rehabilitation.³³

Does tinnitus from a concert go away?

What you hear: ringing, buzzing or roaring that nobody else can hear.

Tinnitus is hearing sound with no outside source. NIDCD says loud noise can cause tinnitus that may fade, or in some cases last for life.²² Noise is one known cause, not the only one.

A 2022 global meta-analysis by Jarach and colleagues in JAMA Neurology pooled studies to estimate that 14.4% of adults have tinnitus (95% confidence interval 12.6-16.5%), and 2.3% have it severely - more than 740 million adults worldwide, with more than 120 million perceiving it as a major problem.³⁴ Prevalence rose from almost 10% at ages 18 to 44 to almost 24% at 65 and older.³⁵

For the US, NIDCD's quick statistics page, citing a 2016 study by Bhatt and colleagues in JAMA Otolaryngology-Head & Neck Surgery, says roughly 10% of US adults, or about 25 million people, have had tinnitus lasting at least 5 minutes in the past year.³⁶

What are the WHO noise guidelines?

What you hear: the steady wash of a highway, trains, planes on approach.

In 2018 WHO Europe published recommended levels, by source, for long-term outdoor noise at the home. They use Lden, a 24-hour average with 5 dB added to evening and 10 dB to night sounds, and Lnight, the average over the night period. Both are annual averages measured outside, so they cannot be compared directly with a dBA reading from a phone app.

Values and strength labels are from the executive summary of the guidelines document itself, WHO Regional Office for Europe, "Environmental noise guidelines for the European Region" (ISBN 978 92 890 5356 3), where "strong" and "conditional" are the guideline group's own grades.³⁷ WHO gave no night value for wind turbines because "the quality of evidence of night-time exposure to wind turbine noise is too low to allow a recommendation."³⁷

A 2022 WHO compendium repeats the night values and links excessive noise to heart disease, hypertension, sleep disturbance, hearing impairment, tinnitus and cognitive impairment.³⁸

These are guidelines, not law. The EU's own reporting thresholds (55 dB Lden, 50 dB Lnight) sit above them, which is why the EEA reports exposure against both.²

What decibel level is safe for sleeping?

What you hear: a truck downshifting at 3am, a late flight, a neighbor's bass.

WHO's 2009 Night Noise Guidelines for Europe set 40 dB Lnight,outside - an annual average at the facade - as the target to protect the public, including children, the chronically ill and the elderly. Countries that could not reach 40 dB in the short term were given an interim target of 55 dB.³⁹ It was WHO's main night value until the 2018 source-specific numbers.

As reported by IEMA, the 2009 guidance laid out effect thresholds: below 40 dB, not enough evidence of harm; 42 dB, a threshold for waking at night or too early; 50 dB, a threshold reported for heart attacks; above 55 dB, cardiovascular effects become "a major health concern." Evidence was rated strong for arousal, sleep-stage changes and awakening, and limited for hypertension, heart attacks and depression.⁴⁰ Noise can change sleep stages without fully waking someone.

The EEA's 2025 report estimates that each year transport noise leaves about 4.6 million Europeans severely sleep disturbed and almost 16.9 million long-term annoyed - annoyance being a health outcome measured with standardized surveys.² An earlier EEA estimate on a different scope gave 5.5 million highly sleep disturbed and 18.4 million highly annoyed.⁴¹

Why do restaurants get so loud?

What you hear: a room that gets louder every half hour until you are shouting across the table.

People automatically raise their voices in noise - and change pitch and pace - which is called the Lombard effect. A 2011 review by Brumm and Zollinger in Behaviour, marking 100 years since the effect was described, traced it across humans and animals and suggested it may date back more than 300 million years.⁴² In a crowded room, each table talks over the others, which raises the level for everyone.

Can traffic noise cause heart disease?

What you hear: nothing you would connect to your heart - years of a busy road outside.

The evidence comes from observational population studies, which show associations, not proof of cause in any one person.

• A WHO-commissioned systematic review (van Kempen and colleagues, 2018) found high-quality evidence that road traffic noise is associated with ischaemic heart disease, with a relative risk of 1.08 (95% CI 1.01-1.15) per 10 dB Lden across seven longitudinal studies - about an 8% higher risk. The same review rated hypertension studies as mainly cross-sectional with high risk of bias, and the evidence on stroke, diabetes and obesity as moderate to very low depending on the noise source.⁴³
• The EEA, in March 2025, described newer studies as "consolidating" links between transport noise (especially road) and ischaemic heart disease, stroke and heart failure, and type 2 diabetes. It called evidence for depression, dementia and cancer limited or emerging, and said some effects are seen from 45 dB Lden.⁴¹

Most cohort studies are European. For the road side of this, see traffic noise. A relative risk of 1.08 is small for an individual and adds up mainly across very large populations.

The WHO review's own authors flagged the limits: beyond the ischaemic heart disease finding, they described the available studies as mostly cross-sectional and "suffering from a high risk of bias," and they concluded that "we need more and better quality evidence, primarily based on longitudinal studies."⁴⁴

How many people are affected in Europe?

What you hear: the background of most cities.

The European Environment Agency's report Environmental noise in Europe 2025 (published 24 June 2025, data year 2022, with a corrigendum to the health figures added 27 March 2026) estimates:²

• More than 20% of Europeans live with transport noise at or above 55 dB Lden, and more than 30% when measured against WHO's levels.
• Road noise affects about 92 million people at that level, rail about 18 million and aircraft about 2.6 million.
• Each year: 73,000 premature deaths, about 49,000 new cardiovascular disease cases, 23,000 new type 2 diabetes cases, and 1.5 million healthy life years lost (years of healthy life lost to illness, disability or early death).
• An economic cost of at least EUR 100 billion a year, about 0.6% of GDP.

The EEA's separate indicator (3 October 2025, same data year) gives about 89 million for road at 55 dB Lden or above and 57 million at 50 dB Lnight or above.⁴⁵ The EEA judges the EU's goal of cutting chronically disturbed people by 30% by 2030 unlikely to be met.²

Do airplanes affect children's learning?

What you hear: a classroom that pauses every few minutes for a jet.

The RANCH study, published in The Lancet in 2005 by Stansfeld and colleagues, compared children near airports in three countries.⁴⁶ It covered more than 2,800 children aged 9 to 10 at 89 primary schools near Schiphol, Barajas and Heathrow. Higher aircraft noise was linked to reading-age delays of up to two months in the UK and one month in the Netherlands; road traffic noise did not affect reading and was linked to better recall memory.⁴⁷

A 2017 National Academies (ACRP) review counted more than 20 studies finding aircraft noise harms children, most strongly for reading. It cites a US pilot study by FICAN (2004, 35 schools near three airports) linking noise reduction to fewer failing high-school students, and an ACRP study (2014) finding a significant relationship between aircraft noise and test scores.⁴⁸ The EEA attributes reading difficulties in over 500,000 European children, and behavioral issues in about 115,000, to transport noise.² Flight paths and airport noise rules are in the aircraft section.

What is misophonia vs hyperacusis?

What you hear: ordinary sounds that feel painfully loud, or one particular sound - chewing, breathing - that is hard to bear.

Both describe reduced tolerance to sound; definitions and treatment are still debated.

• Hyperacusis: the ICD-10 code H93.23 describes it as "an abnormally disproportionate increase in the sensation of loudness in response to auditory stimuli of normal volume." Clinicians Jastreboff and Jastreboff (2023) describe it as a reaction that depends only on a sound's physical characteristics.⁴⁹
• Misophonia: a 2022 expert panel (Swedo and colleagues, using a modified Delphi process with an 80% agreement rule) produced the first consensus definition: "a disorder of decreased tolerance to specific sounds or their associated stimuli."⁵⁰ Jastreboff and Jastreboff describe it as depending on a sound's meaning and context rather than its loudness.⁴⁹

Population figures are scarce. For misophonia in the US, a 2025 presentation by Dixon, posted by Duke University's psychiatry department, reports that 4.6% of a random household sample of 4,005 US adults, described as representative of the adult population by Census measures, met criteria for misophonia.⁵¹

Are there safe listening standards for headphones and venues?

What you hear: a phone warning that you have hit your weekly listening limit; a festival with a quiet tent.

WHO and the International Telecommunication Union published a voluntary standard for personal audio, ITU-T H.870 (2019). Devices track a weekly "sound allowance" against a reference exposure: 80 dB for 40 hours a week for adults (Mode 1) and 75 dB for 40 hours a week for children (Mode 2). Its features include dosimetry, a personal listening profile, automatic volume limiting and parental volume control.⁵²

In 2022 WHO added a Global standard for safe listening venues and events, with six features: cap average levels at 100 dB LAeq over any 15 minutes; monitor continuously with designated staff and calibrated equipment; optimize acoustics and sound systems; provide hearing protection; offer quiet zones; and provide training and information.³² Both standards are voluntary unless a government writes them into law. How venues and neighbors negotiate sound is covered in nightlife.

In a September 2022 CDC survey of 4,514 US adults, 54.1% agreed venue sound levels should be limited, 75.4% wanted warning signs, and 61.2% said they would wear hearing protection if provided.⁵³

What NRR earplugs do I need for a concert?

What you hear: the show, a bit duller - or no change at all if the plugs are not in properly.

US hearing protectors carry a Noise Reduction Rating (NRR), required by the EPA on labels since 1979. It comes from lab tests on 10 subjects and was meant to predict the minimum protection for 98% of users.⁵⁴ Real-world protection is usually lower: OSHA's technical manual says labeled NRRs often overstate actual protection because most workers are not fit-tested,⁵⁵ and a 1996 review of 22 field studies found labels overestimated real protection by 5% to 2000%.⁵⁴

So agencies "derate" the label:

• OSHA Appendix B: with dBA measurements, subtract 7 from the NRR, then subtract the result from the A-weighted TWA.²⁸ OSHA guidance also applies a further 50% safety factor.⁵⁴
• NIOSH counts earmuffs at 75% of the NRR, formable foam plugs at 50% and other plugs at 30%.⁵⁴

A worked example (our arithmetic): foam plugs labeled NRR 33 at a 100 dBA show. OSHA's method gives 100 - (33 - 7) = 74 dBA as a lab-style estimate; with the 50% safety factor, (33 - 7) / 2 = 13, so about 87 dBA at the ear - still above the 85 dBA level at which NIOSH recommends hearing protection.

NIDCD stresses that fit matters: plugs must be inserted properly, cutting foam plugs reduces protection, and custom musician's earplugs let in more natural sound.⁵⁶

In Boston

The rules in this section are national: in Boston, as across the US, OSHA's 90 dBA PEL and 85 dBA action level are the federal workplace rule, and NIOSH's 85 dBA REL is the federal health recommendation.²⁷²¹ The WHO and EEA figures are European and are not limits in Massachusetts.

The Massachusetts study closest to these questions is the Department of Public Health's Logan Airport Health Study (May 2014), which covered 17 communities fully or partly within five miles of the airport, including Boston. It grouped residents by Massport's modeled aircraft noise contours - 65 dBA DNL and above as high exposure, 60-64 dBA as medium, below 60 dBA as low - and found "no statistically significant differences with respect to hearing loss" between the high and lowest exposure areas, for adults or children.²⁴ Its elevated respiratory findings were tied to modeled air pollution, not noise, and it found no statistically significant differences in cardiovascular outcomes.²⁴

Elsewhere in the world

• Europe: the EEA reports exposure against both the EU's 55 dB Lden threshold and WHO's stricter values.²
• Global: the WHO-ITU device standard (2019) and WHO venue standard (2022) are written for any country to adopt.⁵²³²

Where to go for help

Start with a doctor or audiologist. For public references: NIDCD on hearing loss and protectors,²²⁵⁶ NIOSH and OSHA on workplace exposure,²¹²⁷ and the EEA on Europe's figures.²

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