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Does Carbon Dioxide (CO2) Affect My Sleep?

Dianna Smith

In a world very concerned with carbon emissions, understanding the potential effects of CO2 on sleep is crucial to maximizing your wellness.


Research on the direct effects of CO2 on humans is not new; however, recent studies have indicated that carbon dioxide may have more of an impact at lower levels than we previously thought. Specifically, carbon dioxide can influence how well we sleep. 

Before we get into the specifics, let’s talk about what sleep is, exactly, and why it is so crucial to your health.

What Is Sleep?

Sleep is a period of time, usually during the nighttime hours, for your body and brain to rest and recover. 

There are typically five stages of sleep; stage one and two are considered light sleep, while stages three and four are deep sleep. REM, or rapid eye movement, sleep is the fifth stage. REM sleep is also called paradoxical sleep because the body is so relaxed that it is actually paralyzed, but the brain is very active. It is also the stage where we dream the most and our eyes move quickly from side to side. Scientists are continually studying sleep to get a better understanding of the different stages and how they work.

Why Do We Sleep?


The answer? We aren’t sure.

Though scientists have been studying it for years, the primary function of sleep is still unknown. The traditional answer has always been that we sleep because sleep deprivation is detrimental to our health, but this explanation is pretty circular.

While we don’t know for sure the main reason why we sleep, we have some idea of just how necessary it is for all parts of your body. Sleep is critical for learning, memory, and mental health, as well as metabolism, immune response, and tissue repair.

Without sleep, your body will not function properly. Sleep deprivation can lead to weight gain, tiredness, impaired cognitive functions, slow reaction times, and poor memory. Overall, sleep is a key element of wellness and self-care. 

Does Carbon Dioxide Affect Sleep?

Now that we know what sleep is and why it's essential, let’s get to the heart of the matter: does CO2 impact sleep?

Yes, it can.

A 2015 study took a look at the effects that carbon dioxide has on sleeping patterns and cognitive performance. In a college dorm setting, the researchers opened the window in some rooms to manually vent CO2, while other windows were left closed. They recorded the quality of sleep, CO2 levels, and day-after cognitive performance for each student.

The researchers found that the students who slept with the window open during the night, which lowered the CO2 concentration in their rooms, slept significantly better than those with higher CO2 levels. They also performed better on the cognitive tests the day after and reported that the air felt fresher. 

Sources of Carbon Dioxide

The primary source of indoor CO2 is you; as you breathe, you release large amounts of CO2 into the air.


Normally, this would not be a problem, since your exhalations would just mix in with the surrounding air. However, our buildings are very economical now and tightly sealed. The CO2 can’t easily escape the room, and the gas builds up over time. In other words, the longer you are in the room, the more CO2 is in there too. This is why the CO2 levels were higher in the dorms with the window closed; the CO2 had no place to go but back into students’ lungs.

How Does CO2 Affect People?

As CO2 levels rise, you get less and less oxygen in each breath. This can cause you to feel sleepy, tired, or less focused. At more extreme levels, carbon dioxide can give you a headache and make you feel dizzy.

As the study showed, higher CO2 levels can make the air stuffy and lower the quality of your sleep. More studies are being done to explore the short- and long-term impacts that CO2 has on our bodies.

There are a few simple steps you can take to protect yourself. Opening a window or leaving the door open to the rest of the house will help keep the circulation going and reduce CO2 levels. Making sure your air conditioning and heating system are working will also improve your air quality. 

Want more CO2 information? Check out our guide to understanding carbon dioxide below!

Learn everything you need to know about CO2 here.