Just curious. If you fall asleep in a car with the engine off and the windows all the way up can you eventually use up all the oxygen in the air and asphyxiate yourself if you are asleep long enough or are cars designed not to let this happen?
It would depend on the car, wouldn’t it? I don’t imagine they are all built the same.
Too many air leaks in a typical car. Closing the door doesn’t hermetically seal the compartment. It’s designed to shed water, but it’s not airtight nor watertight.
I, too, don’t believe that cars are that hermetically sealed – if nothing else, I would expect that there’d be some air exchange through the vents.
In the other version of this thread that you posted (which I’ll report to be merged), you mentioned cars with windows “blowing out” in the heat. I’d like to see a cite for that, but even if it’s happened, I would imagine it’s not due to increased air pressure, but more likely due to the materials in the windows expanding in the heat, and having no place to go.
No cars are certainly not hermetically sealed. See this clip of Top Gear trying to fill a car with water. Even the one that filled nicely wasn’t exactly water tight.
The answer is “no”.
Even if they’re not sealed, diffusion may be slow enough to suffocate you. Just saying it’s not sealed is not enough.
Of the two-hundred and eighty-nine million hits on Google for “sleeping in car”, anyone have any cites of someone running out of air while sleeping in a parked car with it’s motor shut off? Thought not.
Oh, you don’t suffocate because of lack of oxygen, but because of build up of carbon dioxide. Is the OP interested if it’s dangerous, or possible?
Either really.
Well then let’s put it another way: of the well more than half a billion cars on the road these days, and the billions on the road in the last century, anyone have any cites of someone dying from CO2 while sleeping in a parked car with it’s motor shut off? Thought not.
Data point: here in the Great White North, I drive about with my windows shut and my vents closed when it gets very cold. I also sleep in my car a fair bit (to the degree that I keep a mattress in the back), also with the windows shut and the vents closed.
A great many data points: a lot of people drive about with their windows shut and their vents closed. A lot of people sleep in their cars with their windows shut and their vents closed.
Even if it were hermetically sealed, you’d have to be in there quite a while.
According to this, humans breath about 550 liters of O2 a day. Air is about 20% oxygen, so that would correspond to about 2700 liters of air. Even a compact car has more interior space than that. Obviously, you can’t breathe up all the oxygen in a given space, but, estimating based on atmospheric pressure at altitude, people can generally handle breathing when there’s only half as much O2 as at sea level. Add in the fact that you respire more slowly when sleeping, you can easily sleep for more than 12 hours in any car big enough to let you comfortably sleep for 12 or more hours before you’d start to be in any danger from lack of oxygen.
The real risk, as other people mentioned, would be CO2 overdose. It looks like CO2 poisoning starts with an elevation of blood CO2 levels of about 25%, but I don’t know how to calculate how that changes as you rebreathe more CO2-rich air.
This is only anecdotal, but I used to sleep in my VW bug ca. 1965 quite often (it was cheaper than a motel room and easier than pitching a tent). Although that car is well known for its tight fitting doors and windows, I never experienced any distress that could be attributed to oxygen starvation or elevated C0[sub]2[/sub] levels. And sometimes I even had a…ahem…companion, who had no problems, either.
Can I really be the first guy to ask, does the situation change if you’ve just eaten a couple of cans of beans?
Mythbusters tested that (“Flatulence Myths”). No.
I can only relate my experience and it was frightening.
1998 i slept inside my 1984 Subaru Hatchback Wagon one bight when i couldnt find a place to sleep and had one friend with me. We fell asleep around 12:30/1am and i woke around 6am. I had a difficult time gathering my awareness. All the windows were saturated with condensation to the point that it looked like it was sprayed with a water bottle as was the dashboard and the door panels. This was in the late spring but it was in the 50s that night. I had twitching in my hands and arms and felt like i couldnt get any air and started to panic. I had to shake my friend to wake him up whether from lack of sleep or oxygen deprivation is unknown. I opened the door and tried to stand up out of the car and found i was very badly cramping in my back and my legs felt unsteady. After a few breaths of the morning air i started to focus and i realized my eyes were blurred previously and had begun to focus. When i sat back in the car and took note of my surroundings i saw that all the windows and the sunroof were all closed. I think we came very close to not waking up though it may have been the body’s effort to stay alive that caused the spasming muscles and the jolt awake in the first place. I hope this helps someone else. If you decide to sleep in your car, lower a window, better safe and cold or attacked by bugs than dead
Apart from the fact that this thread is a 5 1/2 year old zombie, examples of people frequently sleeping in closed up cars indicate that more likely than not you just had a panic attack. The fact that your friend apparently did not have similar symptoms supports that.
Other than the condensation, you’re describing my typical waking ritual.
You all do know that cars aren’t completely sealed right?
Some quick Google-ing and I found this…
https://www.youtube.com/watch?v=Y2jS2dZoWCY
Virtually all cars have these to prevent your ears from popping when you slam the doors and all sorts of problems when the air bags go off.