Are Noise-Canceling Headphones Harmful?

QUESTION

Noise-canceling headphones block out noise by emitting sound. Is listening to that constant sound—sometimes for hours—harmful?

ANSWER

That’s a good question—having sound pouring into your ears for hours at a time doesn’t, well, sound like a good idea. After all, excessive use of earbuds, especially among young people listening to music at high volumes, is being linked to an increase in hearing loss. So what about noise-canceling headphones that fight noise with other noise? True noise-canceling headphones have a pretty sophisticated way of countering noise in your surroundings—they have built-in microphones that detect surrounding sounds, and the headphone speakers then generate audio frequencies that are 180° out of sync with the frequency (pitch) and amplitude (loudness) of the surrounding sound. That’s why they’re called noise canceling. Even when they work at their best, though, you don’t hear total silence when using noise-canceling headphones—and the slight hissing that is heard can make some people feel queasy. But it won’t harm your hearing or your health. Headphones that only cancel noise do not emit potentially harmful radiation as cell phones do. (Note: Noise-canceling headphones that let you also listen to music wirelessly do emit  slight radiation.) However, if the hissing sound bothers you, another noise-reducing option is headphones that don’t emit any noise-canceling frequencies at all but simply block outside sound with layers of foam or rubber that create a seal around the ears. Rather than being harmful, noise-canceling headphones actually might benefit your health. If you’re frequently exposed to loud noise—such as from rumbling trains, loud traffic—wearing noise-canceling headphones may help protect your hearing. However, not all noise-canceling headphones provide adequate protection against extremely loud noises (for example, roaring jets or jackhammers) listened to for extended periods of time. There are specially designed headphones that protect hearing from that kind of noise.

THE VACUUM-CLEANER RULE OF THUMB

What if you also listen to music through the headphones? As long as you keep the volume moderate, enjoying your favorite tunes through your headphones won’t hurt your hearing even if you listen for hours. The louder the volume, though—for instance, if you turn up the sound to tune out distractions—the shorter the amount of time it’s safe to listen without risking hearing loss. Safe volume: A good rule of thumb is to keep your volume lower than the sound of a typical vacuum cleaner (70 decibels). Constant exposure—for eight hours a day five days a week over several years—to sounds at 70 decibels or higher increases likelihood of hearing loss, according to academic research. The Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH) advise that the safe level is below 85 decibels. The National Institutes of Health warns that repeated exposure to even a few minutes of sound over 85 decibels (for instance, being 50 feet away from a diesel truck going 40 mph) raises your likelihood of hearing damage years later. Another clue that you’re keeping the volume too high is what happens when you take the headphones off. Do sounds seem muffled…or do your ears ring or buzz? If the answer is yes, better turn the sound down. Or if you have to turn the music on your headphones down (or off) in order to have a conversation with someone—your volume is too high! Hearing loss isn’t the only danger from loud noise—it also can raise blood pressure and trigger headaches. Low-volume noise may not cause hearing loss but can be harmful in other ways, especially if constant. People who live near round-the-clock noise from automobile or train traffic have higher levels of the stress hormone cortisol than those who live in quiet areas. Elevated cortisol has been linked to high blood pressure and high cholesterol, which increase the risk for heart attack and stroke. By the way, headphones aren’t the only way to get your focus and serenity back in noisy, distracting environments. Try this easy “green” way to restore your concentration—and your spirits!