can cause emotional shifts, including fear, sadness, or uneasiness
Most of the sounds we notice each day—like music, speech, or the hum of an engine—fall within a typical hearing range of 20 to 20,000 hertz (Hz). But sound exists on a much broader spectrum. Infrasound, defined as sound below 20 Hz, is one of the least understood parts of that spectrum. Even though we can’t hear it the way we hear voices or music, our bodies might still sense it—and in some cases, react strongly to it.
Whether it’s created by natural phenomena or by machinery, infrasound has been connected to feelings of unease, physiological reactions, and even the communication methods of animals. Here's what you need to know about infrasound, how it works, and why it matters for your hearing and overall well-being.
Key Takeaways
-
Infrasound refers to sound waves below 20 Hz, which are typically outside the range of human hearing.
-
It’s produced by both natural and man-made sources, such as earthquakes, whales, and industrial turbines.
-
Infrasound may affect the human body, potentially causing dizziness, sleep issues, and emotional responses in some individuals.
What Is Infrasound?
Infrasound is any low-frequency sound under 20 Hz, which means it's beneath the threshold of what most people can consciously hear. But just because it’s inaudible doesn’t mean it’s inactive. Infrasound can move through the air and solid materials, traveling long distances and passing through buildings, walls, and even human tissue.
What sets infrasound apart is its ability to create physical sensations rather than audible noise. People may feel pressure in their chest, sense vibrations, or become unsettled—without being aware that sound is the cause. Because of its subtle and often unconscious effects, infrasound is sometimes referred to as a "hidden" sound.
Can Humans Hear Infrasound?
Although our ears aren't built to register infrasound as we do higher-frequency sounds, our bodies may still react to it. Research suggests that exposure to strong or sustained infrasound can influence how we feel physically and emotionally.
Some common human reactions to infrasound exposure include:
-
Dizziness or nausea
-
Headaches or pressure sensations
-
Difficulty concentrating
-
Feelings of anxiety, sadness, or fear
-
Disrupted sleep or restlessness
It’s important to understand that these effects don’t happen to everyone, and they usually require either very high levels of infrasound or prolonged exposure in close proximity to a source—such as certain types of industrial equipment. According to a 2018 NIH study, infrasound can enter the ear and affect the middle and inner ear differently than normal sound, potentially triggering balance-related responses or altering inner-ear pressure.
Infrasound in Nature
How Animals Use Infrasound
In nature, infrasound is often used for communication and navigation, especially among large animals that live in wide or open environments. These sounds are ideal for long-distance signaling because they travel farther than high-frequency sound waves and can move through physical obstacles.
Here are some examples of how animals use infrasound:
-
Elephants use low rumbles to coordinate movement with herd members over several miles.
-
Whales, including blue whales and fin whales, communicate using infrasonic calls that can travel across ocean basins.
-
Giraffes and some reptiles also emit low-frequency sounds to alert others or establish territory.
Infrasound may also help animals detect environmental cues—like approaching storms or earthquakes—before humans are aware of them.
Natural Disasters and Early Warning Signs
Some researchers believe that animals’ sensitivity to infrasound may explain their behavior before natural disasters. For example, before the 2004 Indian Ocean tsunami, observers noted that many animals, including elephants and birds, fled to higher ground hours before the wave struck.
Natural events that can generate infrasound include:
-
Earthquakes
-
Volcanoes
-
Large ocean waves
-
Severe weather patterns (like tornadoes)
Because these events create large-scale pressure shifts, they release sound below the human hearing range—but potentially detectable by sensitive species.
Human-Made Sources of Infrasound
Many of today’s modern technologies generate infrasound as a byproduct of mechanical or industrial function. While these sounds are usually harmless at low levels, ongoing exposure—especially in close quarters—may lead to discomfort for some individuals.
Common sources of human-made infrasound include:
-
Wind turbines, especially those in clusters or wind farms
-
Large machinery, such as engines, compressors, or HVAC systems
-
Airplanes and helicopters
-
Heavy traffic or subway systems
-
Large buildings with specific architectural acoustics
Living near one or more of these sources may expose individuals to chronic low-frequency noise, which could lead to symptoms like fatigue, irritability, or trouble sleeping. Studies are ongoing to determine the extent and mechanisms of these effects. The World Health Organization (WHO) has noted the need for more research on how environmental noise, including infrasound, impacts long-term health.
How Infrasound Affects the Human Body
Impact on the Auditory and Vestibular Systems
The auditory system (which processes sound) and the vestibular system (which helps us balance) are both housed in the inner ear. Infrasound may interact with these systems in ways that are different from ordinary sound waves.
Here’s how that might work:
-
Infrasound may cause minor fluid shifts within the ear, especially in sensitive individuals.
-
It may activate the vestibular system, creating a sensation of motion or imbalance—similar to seasickness.
-
Some researchers believe infrasound can influence pressure-sensitive areas of the ear, triggering discomfort or vertigo.
These effects are subtle and vary by person. People with existing balance disorders, tinnitus, or hearing sensitivity may be more affected than others.
Emotional and Cognitive Responses
While the physical effects of infrasound are more studied, some of its psychological impacts are still being explored. There is growing evidence that certain low-frequency sounds can cause emotional shifts, including fear, sadness, or uneasiness—even when the sound isn’t consciously perceived.
In a famous British experiment, researchers inserted infrasound into a concert without informing the audience. Afterward, nearly a quarter of participants reported feeling strange, anxious, or fearful, despite not noticing anything unusual about the music. This helps explain why infrasound is sometimes associated with “haunted” locations—places where odd feelings seem to arise from nowhere.
Can Infrasound Lead to Hearing Loss?
In most everyday situations, infrasound does not cause permanent hearing loss. That said, ongoing exposure in high-intensity environments—such as certain industrial workplaces—may contribute to changes in hearing sensitivity over time.
Scientists are still exploring the relationship between low-frequency sound and long-term hearing effects. While infrasound doesn’t cause the same immediate damage as very loud high-frequency noise, it may still affect the cochlea (the spiral structure in the inner ear that converts sound waves into nerve signals).
More research is needed, but for those concerned about occupational exposure, it may be wise to consult a hearing specialist for baseline testing and monitoring.
How Is Infrasound Measured?
Because infrasound falls below our hearing range, it requires specialized tools to detect and measure it. These instruments are sensitive to very subtle air pressure changes and vibrations that can go unnoticed by human ears.
Common tools include:
-
Infrasound microphones, designed to pick up low-frequency vibrations
-
Seismometers, which detect infrasound generated by geological activity
-
Barometers and pressure sensors, used in weather monitoring
These devices help scientists track natural disasters, monitor nuclear tests, and study animal behavior. Infrasound also plays a role in environmental science and atmospheric studies.
Is Infrasound Dangerous?
For most people, occasional exposure to infrasound is not a cause for concern. We encounter it regularly—whether we’re aware of it or not—through natural and artificial sources alike.
That said, individuals who are particularly sensitive to sound or prone to inner-ear issues may experience more noticeable effects, such as headaches, fatigue, or sleep disruption. If you suspect that low-frequency noise is affecting your well-being—especially if you live near a consistent source like a turbine, subway, or industrial zone—it may be helpful to speak with an audiologist or physician.
There’s currently no established treatment or protective gear specifically designed for infrasound, but managing exposure levels and identifying the source can make a difference.
Key Conclusions
-
Infrasound is a type of low-frequency sound that we can’t hear but might still feel.
-
It’s produced by nature (storms, animals) and machines (turbines, traffic).
-
While it doesn’t usually pose a health risk, some people may experience discomfort or dizziness, especially with repeated or intense exposure.
Frequently Asked Questions
What is infrasound in simple terms?
Infrasound is sound that’s too low-pitched for humans to hear—anything under 20 Hz. Even though we don’t hear it the way we hear voices or music, it can still move through the air, buildings, and our bodies.
Can infrasound affect your health?
It’s rare, but in some people, strong or frequent infrasound exposure can cause headaches, dizziness, or trouble sleeping. Most people are unaffected unless the exposure is prolonged or very intense.
Do animals use infrasound?
Yes. Elephants, whales, and some birds use infrasound to communicate across long distances or warn others about danger. These sounds travel farther than higher-pitched ones and are helpful in wide open areas.
Can hearing aids block or filter infrasound?
Hearing aids are typically built to amplify higher frequencies—those within the human hearing range—so they don’t offer protection against infrasound. However, they may reduce discomfort from other background noise.
Is infrasound harmful in cities or homes?
Most sources of infrasound in daily life—like distant traffic or appliances—are not strong enough to be harmful. If you’re noticing symptoms, it may be worth checking for louder, persistent sources nearby.
