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:: Friday, May 20, 2005 ::

Carbon monoxide, noise tied to hearing loss - By Nicholas Read, Vancouver Sun
Leroux and Lacerda made their conclusions after studying health reports of more than 8,600 Quebec workers who were exposed to both noise and carbon monoxide in the workplace, or just noise alone.

They found that workers who were exposed to carbon monoxide and noise levels over 90 decibels (comparable to the noise produced by a chainsaw) displayed significantly poorer hearing thresholds at high frequencies than workers who were exposed to noise levels alone.

The reason, Leroux said, is that the human ear needs oxygen to translate sounds into electrical impulses, which are then transmitted to the brain. Cells in the blood carry the oxygen to the ears, and the louder the noise, the more oxygen is required.

But the presence of carbon monoxide, he said, results in decreased levels of oxygen, which means blood cells carrying oxygen to the ear have to work that much harder if the person is going to hear properly.

'If you reduce the amount of oxygen available, you bring those cells to the edge of exhaustion -- metabolic exhaustion,' Leroux said. Do it every day, year after year, he added, and your hearing is going to suffer.

posted 12:40 PM :: reference link :: 0 comments ::

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