What if I told you that tomorrow, you can wake up and be 50% smarter? You might think I was selling a performance enhancing drug. Or lecturing you about smartphones and “sleep hygiene.” Or trying to convince you to quit drinking…But it turns out there’s a much subtler adversary affecting your cognitive performance: carbon dioxide.
Of course, carbon dioxide (CO2) in the atmosphere is a hot topic these days. Levels have risen to 422-ppm and continue to accelerate higher – a trend which has been linked to global climate change.
Less discussed, though, is the much higher concentration of indoor CO2 and how it can affect your health. Every night while you sleep, you exhale CO2, and the concentration in your room climbs. If your bedroom isn’t well ventilated (which it almost certainly isn’t), it’s not unusual to reach over 1000 or even 2000-ppm by morning.
Offices, classrooms, planes, and cars – essentially, anywhere that people spend time in an enclosed space – can all be hotspots for exposure to high CO2 levels.
Here’s the kicker: Even starting at barely elevated CO2 levels, humans experience significantly decreased cognitive function, lower sleep quality, headaches, dizziness, and other symptoms. We could really go down the rabbit hole here, but I think it’s enough to emphasize two of the most important findings:
1. Elevated CO2 makes you dumber. Like, a lot dumber.
Numerous studies have shown that higher CO2 levels result in reduced cognitive performance. There are a bunch of different methodologies, but researchers at Harvard[1] were kind enough to give us results on a simple percentage basis. They found that:
There is no indication that this trend slows down at higher levels. Another research group[2] found that at 2500-ppm, the decline in cognitive ability is, to quote one of the researchers, “astonishingly large[3].”
2. Elevated CO2 ruins your sleep.
As CO2 levels in the bedroom increase, people’s sleep suffers on pretty much every metric[4]. It takes longer to fall asleep, they toss and turn more, the amount of deep sleep decreases, and they subjectively say that they slept worse.
Once again, these effects show up in statistically significant ways, even below 1000-ppm.
These are just a few of the well-studied negative effects. If you’re like me, you might also be wondering what effects this could have on long term health. Unfortunately, we don’t really know. I can’t find long term studies looking at chronic exposure to different levels of CO2, and I imagine those would run into all sorts of practical and ethical issues. But here at Chem Free Guys, we don’t mind leaning on some good old-fashion common sense. And my sense is, if it’s messing with your brain function and affecting your sleep, it’s a pretty good bet that it’s at least not better for your long-term health.
We’re all about practical action here, so the next question is, what can we do about it?
My first recommendation is to start monitoring the air you’re breathing. If you don’t know the quality of air in the places where you spend significant time, you won’t be able to improve it. While there are some CO2-specific monitors, I recommend getting one like the Awair Element, which also monitors for PM2.5s and VOCs.
Here’s an plot of CO2 in my own bedroom overnight, taken from my Awair monitor:
As you can see, the concentration reaches almost [XXX]-ppm. While not terribly high, it’s enough to start being concerned. And this is a large bedroom. Smaller rooms, or more poorly ventilated rooms could see much higher levels.
For me, it’s enough that I want to do something to bring the concentration down. So is there a filter I can buy to take the CO2 out of my room? Unfortunately, no. While CO2 scrubbers exist, they’re big, industrial devices that aren’t practical for home use.
The good news is, there’s a much simpler solution! Since the outside CO2 is generally below 450 ppm, you can just open a window in your bedroom, and the CO2 level will stay much lower. Here’s my same bedroom overnight, but this time with one window left halfway open:
[talk talk talk]
It doesn’t take long to imagine, though, why you might not want to leave your bedroom window open every night. It might be cold, dry, or raining. Or you might live in a city where pollution or noise is a problem. So I tried measuring CO2 levels with the window closed, but my bedroom door open. Here are the results:
[talk talk talk]
Luckily it seems like there are a few easy changes that can improve the air we breathe while we sleep. There may also be other solutions that work, like running your air conditioner on “circulate” mode, turning on the fan in your room, or other things I haven’t thought of. Keep in mind that the results in different rooms will be drastically different, so you should really be measuring this for your own home.
I’ve focused specifically on the bedroom because we all spend a lot of our lives there. But once you have a monitor, I think it’s worth measuring this in other areas where you spend significant time. Your work desk, home office, or crowded meeting rooms could all have elevated levels of CO2 that are harming your health or decision-making.
Overall, indoor CO2 probably doesn’t top the list of most concerning toxins in our modern environment. But depending on the spaces where you spend your time, it could still be having a significant negative impact on your life, and the changes needed to address it are remarkably simple. So it’s at least worth finding out.
To summarize, my overall recommendations are:
We plan to continue testing in more locations and scenarios in the near future, and will post the results here, so stay tuned for more info!
