Background noise or ambient noise is any sound other than the sound being monitored. Background noise is a form of noise pollution or interference. Background noise is an important concept in setting noise levels.
In a study from the University of Montreal, scientists found every 10-decibel (dBA) increase in outdoor noise raises the risk of stroke by 6% for people aged 45 and over.
A stroke is a damage to the brain from interruption of its blood supply. Symptoms of stroke include trouble walking, speaking and understanding, as well as paralysis or numbness of the face, arm or leg.
The researchers used health data of nearly 1.1 million people living on the Island of Montreal from the years 2000 to 2014.
The noise measurements were recorded by approximately 200 sound level meters across the island during the same period.
During the period studied, more than 25,000 people were hospitalized for stroke on the Island of Montreal, or 2.5% of the population aged 45 and over.
The team found there were more than five times as many ischemic strokes (more than 21,000) as hemorrhagic strokes (4,000).
Ischemic strokes occur when a blood clot blocks a blood vessel in the brain, whereas in a hemorrhagic stroke a blood vessel in the skull ruptures.
On the Island of Montreal, ambient noise is highest around busy roads; the findings, therefore, suggest that people living in the vicinity of major arteries are at higher risk of stroke.
This study complements an international report that reviewed 353 scientific articles published between 1980 and 2019 on the health effects of traffic-related air pollution.
Previous studies have found that noise above 40 dBA at night and 55 dBA during the day can cause fatigue, stress, sleep or mood disorders and cardiovascular problems.
Chronic exposure to noise between 85 and 105 dBA poses a long-term risk of hearing loss. At 105 dBA and above, there is an immediate risk of tinnitus or even deafness.
If you care about stroke, please read studies about drug combo that could prevent stroke and heart disease, and what you need to know about stroke rehabilitation.
For more information about stroke, please see recent studies that coffee and tea drinking may protect you from stroke and dementia, and results showing her 2-year-old niece noticed something wrong during a video chat. It was a mini-stroke.
The study was conducted by Larisa Inès Yankoty et al and published in the journal Noise & Health.
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