It’s common knowledge that loud noises can damage your hearing and high-pitched noises can be annoying but can sound also make you sick?

Research suggests that certain sounds can. Exactly how people could use this capability is up for debate.

Sound Sickness?

Ultrasonic Weapons

The U.S. recently evacuated several diplomats from China after they reported feeling sick after hearing strange noises in their apartments. Starting in 2016, U.S. diplomats in Cuba described similar incidents.

The diplomats experienced headaches, cognitive issues, hearing loss, nausea and other symptoms similar to those of a mild traumatic brain injury. Because of these reports, the U.S. issued a health warning to Americans in China.

This has led to accusations of the involved countries using some sort of sonic weapon. Both countries have denied these allegations, and no such device is known to exist, however…


Ultrasound Weapons

As of yet, the events remain unexplained. One theory is that surveillance devices that produce ultrasound are the culprits. These devices would normally emit inaudible, harmless ultrasound. If placed too close together, though, they could interfere with each other and create an audible, unpleasant sound.

That would explain the noise, but it doesn’t explain the symptoms the diplomats experienced. Ultrasound occurs in nature and human-made devices.

Bats use it in echolocation, and doctors use it to see babies in the womb. As doctors use it, it is considered safe.

Ultrasound is sound at extremely high frequencies above 20,000 Hz, and it can heat up tissue if pressed against a person for an extended period.

The U.S. military has tested it as a weapon but found it to be ineffective as it can’t be used at distances.


Infrasound weapons

Another explanation that’s been put forth is the use of infrasound, sound lower than 20 Hz. Infrasound occurs in nature and human-made devices as well. Earthquakes, ocean waves, and lightning create it. Some animals, including elephants and giraffes, use it too. Human-made devices, such as wind turbines, can also generate it.

Infrasound has been shown to have impacts similar to those reported by the diplomats in China and Cuba, including headaches, nausea, dizziness and fatigue.

Because of infrasound’s long wavelength, it can penetrate the human body more easily than other waves. The infrasound then creates an oscillating pressure system and vibrates liquids and gases within the body. This can cause muscle contractions, which can cause the symptoms mentioned earlier if it goes on for long enough.

Sonic Weapons

Sonic Weapons

Early reports of the incidents in China and Cuba blamed them on some kind of high-tech sonic weapon. Nobody has found evidence of such weaponry, and many experts are skeptical that anything like it exists. But could it be possible for someone to build an infrasound weapon?

Sonic weapons do exist, but none that are as subtle as this weapon would have to be. Flashbang grenades, for example, create a bright flash of light and a loud noise of about 170 decibels (dB), about 50 dB higher than the threshold where sound starts to cause pain.

Acoustic-hailing devices such as the Long Range Acoustic Device can produce painful tones and cause hearing damage if discharged to close to people. They’re sometimes used for things like crowd control.

Creating infrasonic devices is possible. You just need a very large speaker that can play extremely low frequencies. Tests of these devices have shown that they’re not particularly effective, however. The sounds didn’t seem to bother the monkeys and minipigs the devices were tested on.

So, can sound make people sick? Potentially, yes. It can have some real physical effects on the human body that can be uncomfortable.

It seems unlikely, though, that someone has weaponized this, but it’s not entirely out of the question either. If that were the case, this weapon would be something the world has never seen before.