Hypertension is one of the main risk factors for premature death worldwide and it is estimated that around one third of adults suffer from it, even if they are not aware of it.
Tobacco, excess salt, alcohol or pollution are some factors that increase tension, but there is a threat that is not usually taken into account: noise.
Although it is annoying, the relationship with blood pressure or respiratory diseases is not as intuitive as the one that exists with the smoke of cars and, in addition, there are not many scientific studies that demonstrate the link.
Even so, both excessive noise and pollution were included in 2021 by the European Society of Cardiology among the aspects that can be modified to reduce the risks of hypertension in the population.
A team led by Jing Huang, a professor at the University of Peking (China), has just published a study in the journal
in which the relationship between traffic noise and hypertension is reinforced.
The researchers collected information from the UK Biobank on more than 240,000 people aged 40 to 69 who did not have high blood pressure.
They followed them for an average of eight years, estimating the noise they were exposed to based on the address in which they lived, and recorded how many developed the ailment.
Car noise affects children's cognitive development
There were more than 21,000 and the data shows that the risk of excessive blood pressure is related to the noise dose to which they were exposed.
Furthermore, they were able to separate the effect of noise from that of pollution, but found that the damage is compounded when both are combined.
“It seems possible that high exposure to polluted air leaves the body more vulnerable to the dangerous effects of traffic noise and vice versa,” they write.
The researchers have obtained more reliable evidence of something that is difficult to demonstrate and provide arguments to those who defend that regulating traffic, reducing both noise and air pollution, is a useful measure to reduce cardiovascular health problems and other diseases throughout the world. the population.
Julio Díaz, a researcher at the Carlos III Health Institute, believes that these results "are important to include the noise associated with traffic as a cause of many health problems."
"We published a study in which we calculated the number of cars circulating in an area and hospital admissions were related," says Díaz, who has participated in several investigations on the impact of noise on health.
In the analysis, published in 2015, they estimated that lowering traffic noise in the Community of Madrid by one decibel would mean avoiding 468 premature deaths per year.
As Díaz points out, "in low-emission areas, they only think about the benefit of reducing" nitrogen dioxide, but "the noise is not looked at" despite the relevance of its effects.
The traffic, 80% of the noise
Carlos Escobar, a cardiologist at the La Paz University Hospital in Madrid, agrees that "the noise to which we are exposed is not sufficiently monitored."
“High-pitched noise is easy to detect, like someone screaming or a machine under the house, but chronic loud noise can be more dangerous, because you get used to it,” he says.
"Over time, it can increase blood pressure and be a variable that later increases the risk of stroke or heart attack," he continues.
Escobar emphasizes the importance of controlling the noise from cars, which in Madrid could account for 80% of the total, but also points out "to the conditions of the workplace or to what we do at home, where we can play loud music for a long time or video game".
“If you do it chronically, it can be bad, not just for your hearing,
Your body experiences noise as an attack, and when you need to repel an attack, the first thing you do is increase your blood pressure."
Julio Díaz, Carlos III Health Institute
Díaz also points out the danger of those pleasant sounds at many decibels: "There is a subjective component and, although the noise you want to hear is not the same, like a song at a high volume, the impact it has is the same."
“People may think that they get used to noise, and those of us who live in cities like Madrid get used to the noise of cars, but our bodies don't get used to it,” he warns.
“Studies in which blood has been taken from people before and after subjecting them to noise have shown that there are higher levels of glucose, cholesterol or cortisol, which is the stress hormone”, he affirms.
“The simplified explanation would be that your body experiences noise as an attack, and when you need to repel an attack, the first thing you do is increase your blood pressure and heart rate,
and pour substances such as cortisol into the bloodstream ”, he explains.
“High levels of substances such as cortisol weaken the immune system and facilitate respiratory infections, and chronic cellular inflammation produces many other health problems,” he summarizes.
The study authors see their findings as a wake-up call to authorities to alleviate the impact of traffic noise as part of a social effort, applying stricter control measures, improving roads and urban design, and encouraging investment in quieter vehicles.
In addition, they point out that people living in the poorest areas had a significantly higher risk of developing hypertension than people in the more affluent areas.
For this reason, they propose, "changing the physical environment of these areas could generate greater absolute benefits and should be prioritized."
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