Forget stress, air pollution may also be the reason for your poor sleep, says study

Air pollution may be one of reasons for poor sleep, according to some researchers who are studying the effect of toxic air on our sleep. The study analysed the amount of time the participants spent asleep at night as compared to their waking hours---a measure also known as sleep efficiency.

The findings of the study tell us that more the exposure to nitrogen dioxide and small particulates, more will be the chance of having low sleep efficiency. That could be the effect of air pollution on the body.

“Your nose, your sinuses and the back of your throat can all be irritated by those pollutants so that can cause some sleep disruption as well as from breathing issues,” said Martha Billings, assistant professor of medicine at the University of Washington and co-author of the research.

Billings further added that the entry of pollutants in the blood stream could affect the brain and regulation of breathing.

Higher levels of nitrogen dioxide increased the chances of having low sleep efficiency by almost 60% while exposure to higher levels of PM 2.5s increased the chances by almost 50%.

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The study captured air pollution data for nitrogen dioxide and PM2.5 levels over a 5-year period in six US cities and includes data from near 1863 participants’ homes. The data was utilised then to get estimates of pollution levels in the homes.

Data was captured by the researchers with the help of medical grade devices which the participants wore on their wrists for a period of seven continuous days to monitor their small movements while they slept. This method provided an insight into the sleep and waking hours of each participant. 
From the results, the researchers grouped the participants according to their sleep efficiencies. They found that the top one fourth of the participants had a sleep efficiency of 93% and higher, while lower one fourth of the participants had a sleep efficiency of 88% or lower.  All the participants were then divided into four groups based on their exposure to air pollution.

The researchers also took into consideration a variety of factors such as age, smoking status and presence of obstructive sleep apnoea, after which they concluded that those participants who had the maximum exposure to air pollution in the five years tended to be in the bottom group for sleep efficiency and those who had minimum exposure.

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Higher levels of nitrogen dioxide increased the chances of having lower sleep efficiency by 60% and higher level of PM2.5 particulates increased the chances by 50%. Higher levels of air pollution were also connected to greater time spent awake after going to sleep.