What Are Decibels and How Can They Affect Hearing Health?

Oct 01, 2023

Fact Checked

A simple guide to understanding decibels and learning how to protect your hearing health.

Written by: Miranda M. Riva, Esq

Medical Reviewer: Brad Ingrao, AuD

Reviewed by: Kathleen Cameron, BSPharm, MPH, Senior Director, NCOA Center for Healthy Aging

Key Takeaways

Sound levels are most commonly measured in decibels (dB), which range from barely audible to loud enough to cause physical pain.
Sounds below 70 decibels are safe, while sounds above 70 decibels are harmful.
Prolonged exposure to sounds louder than 85 decibels can damage your hearing.
Sixty decibels is equal to the sound of normal conversation, 90 decibels is closer to a lawn mower or hair dryer, and 120 decibels is more like a siren on an emergency vehicle.
Exposure to sounds at 120 decibels may cause discomfort, and 140 decibels is considered the threshold of pain.

Whether the cause is genetic, age-related, or environmental, approximately 48 million Americans have some degree of hearing loss. ^[1] Preserving your hearing health is important for basic communication, balance, health, and even brain acuity. ^[2] Regardless of your age or your degree of hearing loss, it’s important to limit excessive noise exposure and use protective equipment when you’re around loud sounds for extended periods of time.

Our Reviews Team assembled this guide to help you better understand decibels, the measurement of sound, and how sound impacts your hearing health.

What are decibels and why do they matter?

A decibel is a measurement that expresses the relative intensity of a sound pressure level (SPL). ^[3] This is calculated relative to the threshold of human hearing, which is 0 decibels. Decibels are essential for setting guidelines and safety standards for sound exposure limitations. Rather than setting a subjective standard (how loud a sound is to the subject), the objective nature of a decibel measurement, which measures how intense the sound energy is in a confined space, makes regulation significantly easier. ^[4]

How sound is measured

Sound is measured in decibels, which are measured on a logarithmic scale. The two types of scales for measurement are linear and logarithmic.

A linear scale is used for measuring the space between two points, like distance and length. In contrast, a logarithmic scale is used to measure values based on human perception, which has a broad range of possible quantities, like power and intensity.

Brightness and sound are both examples of values measured on the logarithmic scale. The larger the decibel, the more intense the sound. ^[3] As sound intensity increases, our ears become less sensitive to small changes.

Safe and unsafe decibel levels

Sound data sources: Noise Sources and Their Effects and Levels of Noise in Decibels. ^[5] ^[6]

How is hearing loss measured?

Hearing loss is measured using a chart called an audiogram, which plots a person’s hearing thresholds in each ear. ^[7] For example, a person can have no degree of hearing loss in their right ear but have moderate hearing loss in their left ear.

“An audiogram is expressed using decibels hearing level (HL) rather than decibels sound pressure level,” noted Brad Ingrao, AuD, a practicing audiologist since 1992 and active member of the Hearing Loss Association of America. He further explained this is because “[Decibel sound pressure level] is the actual physical measurement of the sound energy,” whereas “[Decibel hearing level] is a conversion of decibel sound pressure level to normalize the audiogram graph relative to how people with normal hearing hear pitch.” In other words, an audiogram measures a person’s degree of hearing loss by comparing their results to a graph of how a person without hearing loss hears.

Each threshold in the table below represents a range of decibels, which may be hard for a person of the indicated hearing loss degree to hear. ^[8] For example, an adult with no hearing loss can generally hear sounds above 25 decibels but may have trouble hearing decibels between 0–25 decibels. Alternatively, an adult with severe hearing loss can generally hear sounds above 90 decibels but may have trouble hearing sounds below and between 71–90 decibels.

Table 2 Degrees of hearing loss

Degree of hearing loss	Adult hearing thresholds (dB)*	Description
None	0–25	Hearing within the normal range
Mild	25–40	Difficulty hearing distant or faint speech
Moderate	41–55	Difficulty hearing conversational speech
Moderately severe	56–70	Difficulty hearing most speech
Severe	71–90	Difficulty hearing loud speech and environmental sounds
Profound	>90	Difficulty hearing even very loud sounds

*The cutoff points for each threshold may vary slightly among practitioners and publications.

How do I know if a sound is safe?

According to the National Institute on Deafness and Other Communication Disorders, “Long or repeated exposure to sound at or above 85 decibels can cause hearing loss.” ^[9] The higher the decibels, the shorter the exposure time is before hearing damage may occur. For example, a motorcycle (95 decibels sound pressure level) can cause damage to hearing after about 50 minutes of exposure, but being around a jet plane taking off with no hearing protection gear can cause immediate damage or even cause eardrums to rupture. ^[10] According to Sumeet Kumar, PhD, who is a geneticist and the founder of GenesWellness, this is because “the inner ear has tiny hair cells that vibrate when hit by sound waves, which translates them into signals the brain understands as sound. Loud noises can damage these delicate cells, resulting in hearing loss.”

Even if you’re around sounds less than the 85-decibel threshold, you may not experience discomfort or actual pain in your ears, but you may become annoyed with the loudness. The physical effects of intense sound are just one way to tell if the sounds you’re hearing may be unsafe for an extended period of time. Thankfully, there are a couple of ways to measure whether a sound you’re around is at a safe level.

How to measure decibel levels

The most basic way to measure sound is by using a sound level meter. Stores, like Home Depot, sell hand-held sound level meter devices that show the decibels on a screen with an accuracy within 1.5 decibels. If you have a smartphone, you can choose from various phone applications to work the same way using the microphone on your device.

NIOSH Sound Level Meter App (Apple device application store)
NoiSee (Apple device application store)
Sound Meter – Decibel & SPL (Android device application store)

If you have an Apple Watch Series 4 or later, you can use the Noise App, which pushes an alert when your phone microphone detects decibels that may cause hearing loss if exposure continues for an extended period of time (determined by the decibels detected).

Protecting your hearing health

According to Kumar, even just “a single loud blast can cause irreversible damage, affecting one’s hearing permanently.” One of the easiest ways to protect yourself against hearing loss is to limit exposure to loud noises. This can be in small increments, like reducing the volume in headphones or earbuds when listening to music or audiobooks, or on a larger scale, like opting out of events you know will exceed the recommended exposure.

General hearing health protection tips:

Be mindful of the volume on your devices (television, smartphone, and tablet), and reduce the volume when you can.
If using headphones or earbuds, keep the volume low and take frequent breaks.
Use quiet products when possible (for example, purchasing quieter appliances and power tools).
Use hearing protection, like earplugs, if you’re going somewhere potentially loud and can’t control the volume (for example, in a movie theater or at a school play).
Look for notices (through email or on paper flyers) with warnings of excessive noise and avoid locations accordingly.

As with many factors impacting your health, there are some you can control and others you can’t. Those out of your control include workplace noise, outside ambient sounds, and live events. Just because the intensity of these sounds is out of your control, doesn’t mean you can’t use protective gear to keep yourself safe.

Occupational noise

Hearing loss is one of the most common disabilities claimed by veterans of the U.S. armed forces and is one of the reasons those who work on aircraft carriers (140 decibels sound pressure level) and other flight decks are required to wear protective gear. ^[11]

Noise is a unique workplace hazard because exposure also occurs outside the workplace. ^[12] For example, even if a regulation limits exposure to decibel levels for a plant worker to five hours daily, the same worker can still surpass the limit just by walking around outside after work. In contrast, a person exposed to radiation or toxins in the workplace will likely only come into contact with the hazard at work and nowhere else, making it easier to regulate and protect workers. If you’re working in a loud work environment, like in the military or in construction, follow the protection tips below.

Occupational noise hearing protection tips:

Wear the required protective gear (ear plugs, ear muffs, noise-canceling headphones) and consider purchasing even stronger protective gear than required.
If possible, choose a job where you’re around loud noises less frequently or request a position change in a quieter location.
If you have control over the equipment used, consider purchasing quieter tools.
If you’re working in an environment where no noise protection is advised and you’re noticing hearing loss, contact your local Occupational Safety and Health Administration branch and learn about your options.
Take advantage of disability and other programs if hearing loss occurs while working in a loud environment.

Live events

Live concerts and other events can be fun, but they can also cause temporary and sometimes permanent hearing damage if they are too loud for too long. Since these are usually events you choose to attend, be mindful of how often you’re going, how long the event will be, and whether the venue is enclosed or open air. Enclosed venues often amplify noise, but even events at open-air venues can be harmful to your ears.

Live event hearing protection tips:

Opt out of unnecessary and easily avoidable events.
Use protective gear, like foam earplugs, ear muffs, or noise-reducing ear plugs, which still let sound in but work to reduce excessive noise (these are a great alternative for concerts when you want to hear music but still protect your ears).
When you’re somewhere, like a concert or sporting event, sit somewhere far from the loudspeakers.
If possible, take breaks by walking away from the venue and having time away from the loud noises.

Bottom line

Decibel measurements are important because they give us a standardized and versatile means to quantify sound levels across a broad range. This enables us to not only understand hearing loss and find treatment options but also helps us set sound-related safety standards in the workplace and in everyday life. If you’re worried about whether a sound you’re around could be damaging to your hearing, download one of the smartphone applications above, or purchase a sound level meter from your local hardware store. This way, you can test the sound around you and ensure you stay safe.

Have questions about this review? Email us at reviewsteam@ncoa.org.

Sources

Hearing Loss Association of America. Hearing Loss Facts and Statistics. Found on the internet at https://www.hearingloss.org/wp-content/uploads/HLAA_HearingLoss_Facts_Statistics.pdf
Russ, Shirley A, et al. A Life Course Approach to Hearing Health. Nov. 21, 2017. Found on the internet at https://www.ncbi.nlm.nih.gov/books/NBK543714
UNSW School of Physics. dB: What is a decibel? Retrieved July 26, 2023. Found on the internet at https://www.animations.physics.unsw.edu.au/jw/dB.htm
Centers for Disease Control and Prevention. What Noises Cause Hearing Loss? Nov. 8, 2022. Found on the internet at https://www.cdc.gov/nceh/hearing_loss/what_noises_cause_hearing_loss.html
Purdue. Noise Sources and Their Effects. Found on the internet at https://www.chem.purdue.edu/chemsafety/Training/PPETrain/dblevels.htm
American Academy of Audiology. Levels of Noise in Decibels (dB).2010. Found on the internet at https://audiology-web.s3.amazonaws.com/migrated/NoiseChart_Poster-%208.5×11.pdf_5399b289427535.32730330.pdf
The National Hearing Test. How to Read an Audiogram and Determine Degrees of Hearing Loss. June 3, 2014. Found on the internet at https://www.nationalhearingtest.org/wordpress/?p=786
University of Iowa Health Care. How to Read an Audiogram. March 13, 2019. Found on the internet at https://medicine.uiowa.edu/iowaprotocols/how-read-audiogram
National Institute on Deafness and Other Communication Disorders. Noise-Induced hearing loss. May 9, 2016. Found on the internet at https://www.nidcd.nih.gov/health/noise-induced-hearing-loss
Federal Aviation Administration. Hearing and Noise in Aviation. Found on the internet at https://www.faa.gov/pilots/safety/pilotsafetybrochures/media/hearing.pdf
Defense Technical Information Center. U.S. Navy Flight Deck Hearing Protection Use Trends: Survey Results. May 18, 2006. Found on the internet at https://apps.dtic.mil/sti/citations/ADA455117
Fink, Daniel J. What Is a Safe Noise Level for the Public? January 2017. Found on the internet at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5308171

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