Air pollution is associated with an increased risk of sleep disturbances. Nitrogen dioxide and fine particles are involved.
Take a deep breath of fresh air while you can. Because pollution does not only have an effect on the cardiovascular system or the brain. It is also associated with poorer quality sleep. This link is established by researchers from the University of Washington (United States) at the Congress of the American Thoracic Society, held in Washington DC from May 17 to 24.
This association between sleep disturbances and air pollution was established by monitoring 1,800 Americans for 5 years. The researchers measured the amount of nitrogen dioxide (NO2) and fine particles (PM 2.5) in the air of the towns where these volunteers resided.
Choppy nights
The participants also agreed to wear an activity monitor. This device, made up of an accelerometer and a system for recording body movements, can be used to calculate the quality and quantity of sleep.
It relies, for this, on the relationship between the time spent sleeping and that spent in bed. People with normal nights score 85% and above. This is called sleep efficiency.
The volunteers were separated into four groups, depending on the level of pollution. And sleeping seems less easy in the event of air pollution. The quartile most exposed to nitrogen dioxide is 60% more likely to have poor quality nights.
Within the group most often the victim of fine particle pollution, this risk is increased by 50%. However, the quality of sleep remains fairly good: the least rested quartile obtains an average score equal to or less than 88%.
The usual mechanisms
The authors conclude that in the long term, air pollution should also be considered a risk factor for sleep. The sources in question are mainly linked to urban life. NO2 and PM 2.5 are mainly produced by road traffic and domestic heating.
“Improving air quality would therefore be one of the means of improving sleep and reducing health inequalities,” said Martha Billings, lead author of this study. In fact, some people are more exposed to pollution and its harmful consequences. This is particularly the case for people with low incomes, but also for the elderly – fragile.
According to the researcher, sleep disorders are caused by the usual mechanisms of air pollution. Breathing problems, loss of respiratory capacity are frequent among urban dwellers breathing stale air.
“Air pollution causes upper respiratory tract irritation, swelling and congestion, but can also affect the central nervous system and areas of the brain that control breathing and sleep,” says Martha Billings. City dwellers, in a way, combine risk factors. Because air is not the only source of pollution. City lights and their noises also affect sleep.
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