Cold Air and Colds

Question

My son is four months old. The baby sitter takes the kids outside. It's rather cold and windy here in Japan. Is it dangerous to my son's lungs or respiratory system to inhale cold air?
Japan

Dr. Greene's Answer

For generations, parental wisdom has held that cold air is not good for children’s respiratory systems. In particular, cold air has been thought to cause colds (thus the name). Earlier medical traditions have tended to agree with folk wisdom. Over the last fifteen years or so, the prevailing medical opinion has shifted to a different point of view. The more recent thinking is that cold air does not cause colds, bronchitis, pneumonia, or other respiratory infections. Scientifically designed experiments have been carried out to prove the theory that cold temperatures do not cause the common cold.

Studies conducted at the University of Virginia made the news when healthy adult volunteers cavorted in the snow with few clothes on and were found no more likely to catch respiratory infections than their companions indoors. Subsequently, at McMurdo Station, a US research base in Antarctica, several important studies have been carried out. (What better place to study the effect of cold temperature than Antarctica?) People in isolation at this base tended to get no colds at all — unless visitors came from the outside. Specific viruses that the visitors brought to the station worked their way through the research compound at a rather leisurely pace, approximating the rate of cold acquisition in other climates. This demonstrated that cold temperature itself does not cause colds.

The scientific studies are rather convincing, but let’s consider other known impacts of cold air on the respiratory system. First, cold air affects an important defense mechanism — mucus transport. The entire respiratory system is coated with a very thin layer of mucus called the mucus blanket, which rests on tiny hairs called cilia. This mucus blanket traps particles and organisms before they can reach the lungs. This constantly moving blanket acts as a conveyer belt to move the particles out of the respiratory system. Proper action of the mucociliary blanket depends on the mucus having the appropriate mixture of stickiness (to catch the particles) and fluidity (to move the particles up and out). When this is altered by dry air, irritating chemicals, cigarette smoke, or any other factor, the respiratory system becomes more susceptible to infection. Cold air stimulates an increase in mucus production, but like other substances, mucus becomes thicker in colder temperatures. Thus, inhaled particles are cleared less easily when a person breathes cold air.

The second area where cold air impacts respiratory health is in the nose. The nose is a remarkable organ designed to condition inhaled air in order to protect the delicate lung tissues. Whether the inhaled air has a relative humidity of one percent or ninety percent, the nose adds or extracts moisture so that air reaching the lungs has a constant relative humidity of about 75%. The same is true of temperature. When breathing through the nose, one may breathe in air at 40 degrees Fahrenheit or at 100 degrees Fahrenheit, but within a quarter of a second the air temperature is quickly brought to 98.6 degrees. Many tiny blood vessels are used to affect a temperature exchange. When a person breathes cold air, the tissues lining the nose swell as the capillaries dilate, bringing warm blood to heat the cool air. Excess blood in the nose is the cause of nasal congestion (nasal congestion is backed up blood, not increased mucus). In addition to the congestion, the mucus normally present in the nose becomes increased and thicker. Cold air, by itself, can produce nasal congestion and stuffiness, which again make it more difficult for the body to remove inhaled viruses and bacteria.

The third area of impact is in the lungs themselves. If cold air reaches the lungs, the lungs respond by releasing histamine. In people with sensitive airways or asthma, this causes wheezing. In fact, many theorists believe exercise-induced asthma is actually triggered by room-temperature air reaching the lungs in large quantity due to mouth breathing, rather than directly from exercise itself.

Piecing the available evidence together, I draw a different conclusion than either traditional wisdom or current medical opinion — 1) It is clear that in order to catch a respiratory infection of any type, one must be exposed to the causative organism; 2) If exposed, however, it is more likely that an individual will become sick if he or she has been breathing cold air.

With this in mind, here are some ways to minimize the risk of getting a cold:

  • For those who must be outside in the cold, breathe through the nose to prevent the cool air from getting to the lungs.
  • Drink large amounts of fluids — this can noticeably thin the mucus and make the mucociliary clearance more effective.
  • Wash one’s hands frequently, which will reduce the number of organisms available to enter the mouth and nose.
  • If appropriate, decrease contact with sick children and adults to decrease exposure to respiratory organisms.

As is often the case, when parents and scientists tend to disagree, both sides have important parts of the truth. In synthesizing the two views, a more accurate view emerges.

Last medical review on: September 30, 2009
About the Author
Photo of Alan Greene MD
Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.
Get Dr. Greene's Wellness RecommendationsSignup now to get Dr. Greene's healing philosophy, insight into medical trends, parenting tips, seasonal highlights, and health news delivered to your inbox every month.
47 Comments
Add your comment

Recent Comments

I get colds from been cold and even from having a fan going makes me get colds or even walking my daughter to school on rainy days I get it to. So what you say you can’t is a load of bull lol :/

A beautifully written and well balanced piece. I have had severe asthma since being born at 28 weeks (in 1972 no less). Dr Greene has explained the cold air/asthma question perfectly.
Note to previous comment author ” cold air can make the lungs produce histamine”- histamine can trigger an asthma attack/lung inflammation- you said you were a nurse, were you in respiratory?
Personally I prefer to sleep in a very cool room with a fan on, warm dry air is my nemesis.
Thank you Dr Greene,. I will be keeping up with your writings as much as possible.

I am a retired nurse & have had pneumonia years ago, and several cases of bronchitis. I believe and know for a fact that I am affected by cold weather, drafts that persist in the home (leaking through closed windows and doors). I live in the Pac. N.W. and yes windows, and doors have very cold drafts! If this article is saying no, then I strongly disagree with this! People who are ill by immune disorders, such as Fibromyalgia, or Chronic Fatigue Syndrome for example, and the very young, or the elderly, adding those with respiratory problems “can succumb to persistent coughing, hacking, and chronic pneumonia, bronchitis from very cold drafts!” I’ve waged war every year against the cold indoors, I’ve weatherized, moved, and fought these terrible drafts every single year, but being ill from an weak immune system I continually have chronic respiratory problems! COLD INDOOR DRAFTS CAN CAUSE ILLNESS!

I can’t believe so much disinformation still hangs around about this. I read in a scientific article about 30 years ago the actual answer. Firstly it is an infection, so as pointed out in this article, being cold does not cause colds/pneumonia. You get that from being around infected people. When it cold, people tend to spend more time indoors, so they are more exposed to the causative organisms. Even worse, there is usually less ventilation house of the cold. (Think of how recirculated air in aircraft causes so many infections).

Does cold air aid infection in some way? It may dry the mucous membranes, but you still need to be around infected people to catch it. At the polar stations, rates of infection are much lower as the air is too cold for the organisms to thrive. So cold air will actually help keep you safe from them, it is coming in from the cold to the presence of others that cause it. Especially if you are breathing deeply because of the cold, or exercising in it, as the causative will be drawn more deeply into the lungs.

Finally as to the dry air being a serious cause of these infections, that simply cannot be true or dehydration would lead you to colds and pneumonia all the time.

I have allergic rhinitis and possibly mild asthma.In the past I have mild wheezing after opening the church door inhaling the cold air during winter.Recently I have noticed that when the temperature is very cold at home
I started coughing.I have more coughing during autumn and winter.
I am on dialysis at present 3 times a week.I have observed that I have coughing spells at almost at the end of 3 1/2 hours of dialysis treatment.At home I am o.k. I have experienced coughing after inhaling cold air coming from air conditioner vent.I want to let the readers know
that in my experience cold air may cause coughing and even wheezing in some patients.

At last a I got a convincing article on why I get common cold in cold weather. Thank you Dr. Greene

Interesting article and read.

Is there any medical research and/or publications based on risks, issues or impact cold air has on newborn babies to 3-4yrs old?

i left this COMMENT WHILE AGO–JAN/18 I JUST found this on your comments page

have you found ANY REPLIES that may be of help to me

if so please forward i would really appreciate any help

see below

dr greene
i read your article and the last part makes more sense to me vs to most common thought of other dctors
i have a problem when i am exposed to a BLAST OF COLD AIR on my chest within a second or 2–yes that quickly– i know that i will be SICK — i start to feel QUEEZY –I HAVE TO GO TO BED FOR A COUPLE OF DAYS–I FEEL WEAK–HEADACHE ==AND TYPICAL FLU/COLD SYMPTOMS –ANY HELP WOULD BE GREATLY APPRECIATED==just before the cold blast i was feeling fine==== thank you==my doctor has no idea has done blood tests–but nothing –only thing i can think of is immune system is very low

Thankyou very much for your article of course it makes sense its an interaction between a bacteria/virus and conditions impacting on the body’s ability to defend itself – I have walking pneumonia – it is made much worse when I am in air conditioned environments when icy air is being pumped out into a room. People keep telling me cold can’t do this – can you please educate people and organisations NOT to run their air con systems on icy cold? please – it is ruining my health – and I’m sure many others too, we now have high numbers of children with walking pneumonia in the UK, I’m convinced its since we imported US style air con (which we don’t really need in the Uk!)

I would like that info as well