Air pollution linked to poor sleep, study finds

https://www.theguardian.com/lifeandstyle/2017/may/21/air-pollution-linked-to-poor-sleep-study-finds

Nicola Davis
May 21, 2017

Air pollution might be linked to poor sleep, say researchers looking into the impact of toxic air on our slumbers.

The study explored the proportion of time participants spent asleep in bed at night compared with being awake – a measure known as sleep efficiency.

The results reveal that greater exposure to nitrogen dioxide and small particulates known as PM 2.5s are linked with a greater chance of having low sleep efficiency. That, researchers say, could be down to the impact 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 added that pollutants entering the blood could have an effect on the brain and hence the regulation of breathing.

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After taking into account a host of factors including age, smoking status and conditions such as obstructive sleep apnea, the team found that those who were exposed to the highest levels of air pollution over five years were more likely to be in the bottom group for sleep efficiency than those exposed to the lowest levels.

More specifically, high levels of nitrogen dioxide increased the odds of having low sleep efficiency by almost 60%, while high levels of PM2.5s increased the odds by almost 50%. Higher levels of pollution were also linked to greater periods of time spent awake after going to sleep.

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Scott Weichenthal, an epidemiologist from McGill University in Canada who was not involved in the study, said the research did not prove that air pollution caused poor sleep, but he added: “There is certainly increasing evidence that air pollution affects our body in ways that we didn’t appreciate before.”

Roy Harrison, professor of environmental health at the University of Birmingham, said a link between pollution and sleep was not unexpected. “Previous research has shown associations between nitrogen dioxide exposures and effects upon various physiological and biochemical functions in the body, as well as hospital admissions and mortality,” he said. “It should therefore come as no surprise that such exposures also affect sleep patterns.”