Frequent use of headphones can lead to an increase in the number of bacteria in the ear, which can later lead to infectious diseases. The BBC Science Focus magazine reported, citing the researches of the scientists of Manipul University in India and the Naval Research Medical Institute in Bethesda, Maryland, USA.
The first study found that earplugs increased the population of different strains of staphylococcus, a common skin bacterium, in the ears. In the second case, scientists found that after wearing headphones for an hour, the number of bacteria on the headphones increased 11 times. The research was conducted on a sterile headset used by airlines on airplanes.
According to BBC Science Focus, there is no evidence that the growth of bacteria from using headphones is linked to the frequency of ear infections. However, some studies show that the skin of the ear can be damaged by frequent use of headphones. Through the resulting scratches, bacteria can enter the body and cause infectious inflammation.
Listening to anything too loud through headphones is dangerous to hearing and can damage the thin hair-like structures (cilia) in the inner ear that are so important to hearing: they help receive sound waves and convert them into electrical signals that the brain can "read and understand" as sound.
Exposure to extremely loud noise can damage the cells in these structures, leading to hearing loss. This can happen gradually with prolonged exposure to loud sounds (as is often the case with hearing aids), or it can happen with a sudden loud, sudden noise. Damage caused in either case can lead to hearing loss and other problems with the auditory system.
Earbuds that fit directly into the outer ear are often considered even more dangerous and can damage hearing if used at high volume for long periods because they are even closer to the hair-like structures of the ear and can cause more damage to them.