Could Air Pollution Be Ruining Your Sleep? How To Protect Your Health At Night

June 9, 2023

A wise old woman once said that we spend our lives either on our feet or on our backs, so it’s worth investing in good shoes and a good bed. It couldn’t be more true, though unfortunately a good night’s rest feels increasingly more difficult to come by in this day and age.

When it comes to the all important 8-hours tucked up tight, I say throw caution to the wind and invest in anything and everything pertaining to ultimate relaxation. An eye mask, ear plugs and copious quantities of lavender make regular appearances in my bedroom, as well as a pile of books and plenty of candles to help me unwind.

It’s frustrating when environmental stressors out of our control interfere with the serenity, though. Try as we might with the routine of chamomile tea and a warm bath, sirens, street lamps and air pollution all play a huge role in disturbing our slumber and ultimately result in sleep deprivation. It’s the latter that we’re discussing today and reason you might want to consider an air purifier for wherever you lay your head. (After all, there’s nothing that says “Merry Christmas!” like a giant, whirring, electrical device…)

You’ve likely heard that sleep occurs in a cycle that includes both Rapid Eye Movement (REM) and Non Rapid Eye Movement (NREM) stages. We start off in NREM. We drift off, our heart rate slows and our core body temperature drops. We then enter deep sleep, where restorative processes take place to repair cell damage, consolidate memories and flush out accumulated toxic waste from our brains, such as Alzheimer’s-linked beta-amyloid proteins. After deep sleep, we move into REM sleep, which is where dreams occur as the brain becomes more active.

It’s believed that both REM and NREM play important roles in the brain, though there’s a lot that remains a mystery, particularly with regards to REM sleep. We know about the importance of the body repair and rest that occurs in deep sleep, but what about all that eye movement? A study conducted in 2005 found that depriving subjects of REM sleep (originally thought to be less important than deep sleep) led to a REM-rebound, whereby they were likely to spend more time in REM the next night. Dream intensity was also found to amp up the more REM-deprived sleepers became.  Those mornings that we wake up recalling crazy dreams are often a sign that our time spent head-to-pillow was dominated by REM, which signals less repair work was able to be done that night during deep sleep.

The key is balance, because it was shown that disrupting either NREM or REM led to a decrease in the ability to consolidate memories, suggesting both types of sleep are fundamental to our learning. But back to deep sleep for a minute. Frighteningly, it has been shown that those deprived of deep sleep for just three nights show a marked decrease in sensitivity to insulin, increasing the risk of type 2 diabetes. With many of us reporting fewer than 7 hours of sleep a night on average due to our demanding lifestyles and urban stressors, is it any wonder diabetes is on the rise? Especially because it’s not just about quantity, but also quality. How often is your rest being disrupted by the ping of an email or noise in the neighbourhood?

It’s obvious that deep sleep is fundamental to our waking health, so we really need to be doing all that we can to support it. Surpringly, we might want to start with the air. It’s been known for a while that poor air quality can be disruptive to deep sleep. Particulate matter and nitrogen dioxide can affect our breathing and cause irritation to our nasal passage and throat. With growing global concern about the impacts of air pollution on our health and a report that it cuts an average of 2 years off our global lifespan, we need to make some serious changes stat. Did you know that experts in Sweden have found a linear relationship between air pollution and mental health problems? This is caused by an inflammatory response in the body to toxic compounds in the atmosphere. Not. Good.

One of the problems that occurs when our air becomes more polluted is that oxygen gets booted out. This is a terrible shame, because a recent study has revealed that oxygen is incredibly important for supporting deep sleep. Scientists at the University of Alberta found that when they administered high levels of oxygen to subjects, they remained in a state of deep sleep. At the opposite end of the spectrum, when subjects were exposed to lower-than-normal levels of oxygen, they remained solely in REM sleep, missing out completely on deep sleep. Because we know that both are important, it serves us well to get the level just right.

These findings have huge implications by offering insight into a potential source of therapy for the sleep-deprived and also by highlighting the alarm we should feel as air pollution continues to worsen. If we aren’t getting sufficient sleep because we’re oxygen-starved, we can’t be on top form; if we aren’t on top form, we’re less able to come up with solutions to the problem and it becomes quite a vicious cycle.

I never thought I’d say it, but I don’t think that house plants alone will cut it in our most polluted cities (although I am intrigued by the Devil’s Ivy with added rabbit DNA thought to combat benzene and chloroform! One to watch, perhaps…) We need more trees, fewer cars and fewer VOC’s. Our lives truly depend upon it. For now, I’m off on the hunt for the ultimate purifying device.

Are you concerned about air pollution in your city and how it’s affecting your sleep?


Kat Kennedy is an Arizona-based physiology doctoral student and holistic health advocate writing about science, health, and her experiences as a third culture kid and global nomad. She's @sphynxkennedy everywhere.


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