General Question

Eggie's avatar

Why do you get sick if you have a fan or air-conditioning on while you sleep?

Asked by Eggie (5591points) May 9th, 2012

I would just like to know the mechanics in the whole thing. I know that it is just plain common sense not to do those things but I would like to know the reason why the human body would get sick under those conditions.

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45 Answers

jazmina88's avatar

I think the air stirred up, circulates germs, especially if the fan is blowing towards you.

gailcalled's avatar

You don’t. You can also stand outside or lie on the ground in a sleeping bag in a wind storm and not get sick.

Do your ablutions and particularly wash your hands well with soap and hot water and get into bed. You are safe; turn on the fan or a/c now

DominicX's avatar

That’s sounds sort of like an old wives tale…I’d like to see actual evidence that that’s the case. You don’t catch a cold from being cold either. Most of the time it comes from touching things other people have touched and then touching your face and transmitting the virus.

Eggie's avatar

@gailchild Do you know this as a fact? (Not insulting you or anything please do not take that as an insult) Why I ask you this is because when I do that, I would usually sneeze a lot when I get up. My mother and other people also tells me that I must be crazy to keep the fan or AC on when I am sleeping because I would catch a really bad cold.

JLeslie's avatar

You don’t. You get sick from a virus or bacteria. People all over America and the world sleep with air conditioners or fans, or both at the same time. Maybe your have a mold or dust allergy and the air conditioner or fan is kicking up and blowing in your face the allergens.

gailcalled's avatar

I don know this for a fact.

Excerpts: No. Colds are caused by your body’s susceptibility to a cold virus…

There are a lot of myths and old beliefs from before science fully understood the mechanism of infection by rhinoviruses (the viruses causing the common cold). The idea of being out in the cold weather or in air drafts causing a “weakening” the immune system allowing for infections isn’t true.

JLeslie's avatar

I need to make a correction, molds can actually make you sick like bacterias and viruses. If the filter in the air conditioner is contaminated it can literally make you sick. But it is not the cold temperature or the action of blowing on you itself. Florida tends to have less flu for instance than other parts of the country, and floridians have their air conditioners on 300+ days a year, day and night, plus some fans sometimes.

Eggie's avatar

But wouldnt a fan or airconditioner circulate water droplets in the air that would cause the flu virus?

gailcalled's avatar

Nothing causes the flu virus. It just is.

A fan simply recycles the air, such as the wind does.

Air conditioners may circulate dust or mold spores.

Nullo's avatar

When I had a dorm in college, my roommate put in a window AC unit. It ran almost continuously to the end of the second term. I did not once get sick.

gailcalled's avatar

@Nullo: Perhaps you never allowed yourself to fall asleep.

JLeslie's avatar

@Eggie Listen to @gailcalled, the flu virus is only present if it is. It does not appear all of a sudden when you put on a fan.

wilma's avatar

An air conditioner or fan can make me uncomfortable and have a stiff neck the next day if it blows directly on me. That happens in the daytime too, when I’m not trying to sleep.

But it can’t make you sick.

YARNLADY's avatar

As others have pointed out, you don’t get sick from the fan, but rather from a virus or bacteria that might be blowing around.

SpatzieLover's avatar

I sleep with the A/C set at 67degrees, and have a fan on if it’s over 80 degrees outside (daytime temp). I do not get sick from the breeze or the cool air. Quite the opposite is true for me: If I get too hot, I don’t sleep. When I don’t sleep I don’t heal and therefore am more ill.

Tropical_Willie's avatar

Think my cheapskate sister-in-law started that rumor. No fan or A/C lower electric bill.

marinelife's avatar

You don’t. What makes you think that one does?

tedibear's avatar

I also wonder if the symptoms someone might feel are allergies and not a cold. Akin to what @JLeslie said about mold in an air conditioning filter, a fan could blow around dust that may have allergens that effect you.

Kayak8's avatar

As stated above, pathogens cause disease, not cold temperatures, cool breezes, or wet or anything else. The primary pathogens (germs) are bacteria, protozoa/metazoa, fungi, and viruses. If you are susceptible to allergies, blowing air around could stir up dog hair or other things that trigger an allergic response. As state above, any pathogens in your environment need to have a mechanism to get to you. Air-borne pathogenic organisms could take advantage of a fan or air conditioning aimed right at you.

I sleep with the AC on and a fan blowing right on me every single summer night without incident, but I have a robust immune system and no known allergies.

augustlan's avatar

A further point: Sneezing does not mean you are sick. It means your nose is irritated (by allergies or just dust or whatever). You can sneeze when you are sick, of course, but sneezing alone is not an indication of illness.

gailcalled's avatar

True. I have small but noticeable sneezing fits all the time. I blame it on MIlo, of course.

citizenearth's avatar

Exposed too much to cold air is not good for the body, either by fan or air conditioner. Too much cold air will affect the lungs and your respiratory system.

Kayak8's avatar

@citizenearth In what ways will cold air (what temperature do you define as cold) affect the lungs and the respiratory system? What is your source that, with a typical air conditioner and fan, you could create temperatures that would be damaging?

Nullo's avatar

@citizenearth I work inside a colossal refrigerator, where the temperature hovers between 35 and 40 degrees Fahrenheit. I average two head colds per year. The rest of my sneezing bouts come from dust and the sun.

Yes, cold can be dangerous. If your core temperature falls, you get hypothermia and can die. Cold places a strain on your body in a general sense, and if there are insufficient resources then your body will start rationing, which can weaken the immune system. And as nasty as stubbing your toe is, stubbing it when it’s cold enough is deep, achy agony.

But most domestic environments don’t get cold enough – especially in the summer! – for any of those to be a concern.

JLeslie's avatar

If you already have a cold or flu, being in the cold can lead to bronchitis or pneumonia. Breathing in cold air can be bad, maybe that is where this idea started? But, an air conditioner to keep the temperature in a room reasonable doesn’t really count, because a 90 degree room when someone has the flu is much more dangerous than having the air on. People run fans and put on an air conditioner to keep a room within a reasonable temperature range.

Eggie's avatar

What Nullo said makes a lot of sense. When one is sleeping, the air conditioning unit or the fan can drop your temperature and the immune system could get weak due to rationing of the body resources. If a cold virus or bacteria gets in, the body may be too weak to fight it off therefore one could get sick from having the fan or air conditioner on them. The devices don’t give you the flu but it can weaken the immune system….right?

Kayak8's avatar

@Eggie Not so much . . . Your brain has the ability to regulate your body’s temperature. In addition, when we sleep we use sheets and blankets, etc. to help us find a temperature that is comfortable. The devices do not weaken the immune system. @Nullo is describing an extremely cold environment and not one you could really achieve with an air conditioner in a fan.

Nullo's avatar

@Kayak8 I suspect that an almost-naked skinny person in a small bare concrete room attached to a powerful AC unit might just be cold enough to cause problems. And there’s the deep freezer at work, which they keep at 10F. You have about five minutes in your summer garb before you stop feeling your hands. But nobody works in there without a jacket.

Oddly enough, your immune system sits near the top of the body’s chop list. It’ll be turned down in times of cold, hunger, intense heat, stress, thirst – any time that those resources would be useful someplace else, it gets its budget cut. You need to be healthy if you don’t want to get sick. :s

gailcalled's avatar

@Eggie; Take defeat like a man (or woman). You are safe from evil devices, for now at least.

Getting slightly chilled for several hours, if the blanket slides off and the a/c is on, will do no harm but wake you and signal you to pull the covers up.

madsmooney1214's avatar

it blows germs on you.

Response moderated (Writing Standards)
suziqiluv1's avatar

no, you CAN get sick from getting chilled while sleeping. One of the bodies defenses against germs is our 98.6 temperture, and a drop in body temp allows germs (especially different virus) an opportunity to invade and multiply quickly, one of the quickest/easiest entry points is through the air we breathe.

Eggie's avatar

@gailcalled Well look at that!!!! You can get sick if your body temperature drops. Take defeat.

gailcalled's avatar

^^^ Because Dr. suziqiluv1 has made a pronouncemen? You need to be seriously frozen in order to develop hypothermia, and then it’s not the“germs {especially different virus)..whatever that means… that get you but the cold.

Millions of people have normal body temps. of well below 98.6, by the way. That is the mean.

You can get temporarily stiff muscles if you sleep while feeling chilled.

Repeating myself, here’s data based on scientific studies…

JLeslie's avatar

There was a study done many many years ago about catching colds. The cold weather and being cold did nothing to affect whether a person caught a cold when the virus was introduced directly to the people in the study through nose drops, or it might have been nose soray, I don’t remember that detail.

They also looked at people catching colds from each other and statistically many more people caught the cold if they played cards with the actively sick people than if they just sat in near proximity. This reinforced the idea that when we touch something that a sick person touched we are more likely to catch the cold and washing hands and not touching our faces is a good way to protect ourselves.

I do think part of the reason more colds travel around during winter months is because the cold can cause our nose to run, and then you touch your nose, and if you have a cold virus on your hands, you just might have infected yourself by wiping your runny nose. And, also people are inside more in the winter.

Cold can be very bad when already sick. Pneumonia is a real danger if someone already has a cold or flu.

hundert's avatar

Actually, sleeping on a cold floor or unprotected in cold weather might give you pneumonia. AC or a fan never, they are too weak.

I used to sleep with windows fully open in winter (that’s the way I like it!) and one morning I woke up with my blanket on the floor, my back completely cold and blood everywhere (from nose). I almost died from that pneumonia as doctors told me later. My body was cooled to the point, where it no longer was able to fight bacteria inside my lungs, so they had enough time to multiply and attack my body.

But AC or a fan are weak, I have it on all the time.

Yes, viruses and bacteria cause colds, but when you’re healthy you often don’t even notice you’re sick.

Those who made those tests I’m sure didn’t cool their test group to the point where they could die.

Pneumonia is probably caused by bacteria that we already have in our lungs and the way you make yourself sick is by cooling yourself to the point where your body is so weak that it will allow those bacteria to breed.

For the unbelievers, there was a story on the news maybe 5 years ago, where half of soldiers in baracks got pneumonia, because it was unbelievably cold inside. Even if they all were infected with some kind of bacteria, there is no way half of them would become sick if their immune system were intact.

So, COLD WEATHER/CONDITIONS MAKE YOU SICK indirectly. Grandmas are right after all.

JLeslie's avatar

Pneumonia is not a cold.

Eggie's avatar

Ok then why whenever I have the fan on me when I am asleep, I get up in the morning sneezing?

gailcalled's avatar

As already stated by many, the air stirs up dust and dust mites and tickles the cilia in your nose, aka irritation or allergies.

JoeSmoe's avatar

PROVE to yourself that EMF causes electric fan flu. Run a fan near your bed pointing to a neutral area. After a week of sleeping in that environment you should have the sniffles, a cough, and general malaise. Remove the fan and experience instant recovery.

endercase's avatar

Right, so I have this problem. I experience very short term symptoms of the common cold if I sleep in front of a fan or in a cold room. When I awake I find that my nose has been running and this in turn can give me a sore throat. However, unlike a cold it will last for less then 24 hours unless I sleep in that room for several nights. I am relatively sure that it is an immune response to the conditions that may lead to a weakening of the immune system. Of course I am not a PHD, MD, or DO, and as such my thoughts on the matter are not that important. The point is the symptoms.

Eggie's avatar

Maybe the fan or air conditioner doesn’t cause it, but it may very well contribute to it.

Response moderated (Writing Standards)
1risLest's avatar

Guys! Guys! Let’s let the fan decide. C’mon now folks, is that not reasonable ?

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