Noise induced hearing loss (NIHL) accounts for approximately 16% of all disabling hearing loss in adults and has long been recognised as a costly health issue. Whilst people are generally aware of the dangers that occupational noise can pose, many don’t realise that our favourite recreational pastimes can also damage our hearing. Listening to music is one of these activities and many find it difficult to comprehend that the effect of loud music is comparable to that of high levels of occupational noise.
How long and how loud?
The risk of NIHL is dependent on the level and duration of the noise. The guidelines developed for acceptable exposure to occupational noise are also applicable to recreational noise. These recommend an exposure level of up to 85dB(A) Leq (Level equivalent) over an eight-hour period and for every 3dB(A) increase above this there needs to be a halving in the exposure time in order to prevent hearing damage. An iPod can reach a maximum level of about 120dB SPL (Sound Pressure Level). This is bordering on the threshold of pain. At this level, just listening for more than one minute puts you at risk of damage to hearing. Simply, iPods should not be used at their maximum volume. However, for those people who like listening to their music loud we recommend they limit their listening time to a maximum of one hour per day.
Avoiding dangerous levels
Set the level in a quiet environment. When in quiet surroundings most people keep their iPods at a safe level. It’s in a noisy environment, such as on the bus, that iPods are turned up to dangerous levels to overcome the background noise. A recent study looking at public transport noise levels and iPod use in Auckland found that on our noisier buses and trains approximately 80% of the people were turning their iPods to potentially dangerous levels.
Use a better headphone set
The small earbud earphones come standard with all iPods as they are the cheapest type of headphone to manufacture. Because they do little to attenuate the background noise, users of this kind of earphone are more likely to turn the volume up to dangerous levels while in noise. Over-the-ear headphones can be purchased separately and will block out considerably more background noise, resulting in a lesser overall iPod volume.
Use the max volume limit feature
Recently Apple has incorporated a new feature into their iTunes software which allows the user to limit the maximum output of the iPod. This feature is great for concerned parents as it can also be locked to avoid further changes.
Summary
- Listening at a moderate level poses little risk of causing damage to hearing
- The volume level should be set in a quiet environment to avoid compensating for background noise
- Use over-the-ear headphones to reduce ambient noise and therefore avoid volume compensation
- If listening at loud levels is preferred, limit the time spent listening to a maximum of one hour each day
If NIHL is suspected, a full diagnostic hearing assessment is recommended. At Dilworth Hearing, our friendly and professional team of Audiologists will carry out diagnostic assessments and provide further rehabilitation and advice for your patients.
References
Wall C., Avery J., et al. (1994). “Noise-Induced Hearing Loss of Occupational Origin: A Guide for Medical Practitoners.” Occupational Safety and Health Service. Joint Technical Committee.
Thorne, P. R., Ameratunga S. N., et al. (2008). “Epidemiology of noise-induced hearing loss in New Zealand.” Journal of the New Zealand Medical Association 121(1280).
Joint Technical Committee, A., Human Effects (2005). AS/NZS 1269.1, Standards Australia/Standards New Zealand.
Occupational Safety Health Service of the Department of Labour (2000). A Guide to the Health and Safety in Employment Act 1992.
Scheib, L. (2010). The Contribution of Commuting and iPod use to Daily Noise Dose, The University of Auckland, Masters of Audiology.
