Many people who wear in-the-ear earphones have problems with them hurting and falling out often. There are a few reasons for this, the first one being that today many earphones are round in cross-section. The opening of the ear canal is more oval and varies in shape significantly from person-to-person. This means that phones do not fit snugly and are more likely to drop out. This is particularly during exercise when the user is moving about. The ears are sweaty, and the MP3 player bounces and tugs on the wire, pulling the earphones out.
The problem tends to be worse during activities such as jogging, aerobics, cycling and whilst in the gym. This is due to sweat building up in the ear and lubricating the surface of the earphone. This sweatiness can also lead to ear infections as the water laden skin allows bacteria and fungi to colonise the skin. Swimmers' ear (otitis externa) may follow. This causes inflammation of the outer ear with redness, itching, soreness, pain and discharge. Reduced hearing from the accumulation of dirt and wax in the ear canal also occurs. Outer ear infection spread to the middle ear, causing otitis media.
Heavy iPods, iPhones and MP3 players in the pocket whilst exercising can also cause a problem. They bounce as you run and move about, repeatedly tugging on the cord of your earphones and dislodging them from your ears. However all is not lost. A decent pair of moulded earphones will stay in place much better than a standard pair will. Because the plugs are individually moulded to the canals of your ears they fit like a key in a proverbial lock and are much harder to dislodge. They are often antibacterial, reducing the risk of infections. They do this by killing the bacteria which cause the otitis externa. This includes Staphylococcus aureus, MRSA and other disease causing bacteria.
As well as these advantages they also improve the sound from your earphones. They do this by reducing sound leakage around the poorly fitting earphones. This preserves the higher energy sound waves, improving the bass and midrange sounds. Another advantage of this is that it reduces the irritation of people around you as it lets less sound leak out from your earphones. As well as this you can listen to your music at lower volume as less sound energy is lost, preserving the battery life on your iPod or MP3 player. You can also try securing your iPod so that it does not bounce as much.