I acknowledge this is a stupid question......

[Just Joshin]

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Colds are caused by viruses, so why is it that people think that if you're cold, like if you go out of the house without a coat on and it's 20 degrees, you'll catch a cold?

 

[shopsteward]

Because that's what their mothers told them.

Although for some reason they don't seem to believe the one about hairs on the palms of their hands.

 

[hrandani]

Yeah it's definitely just an old wives tale.

However if it is extremely, extremely cold outside, you can damage or kill the cilia and render yourself more susceptible to bacterial invasion. I think that's right. It's been a while since I read that.

The one where getting wet -> getting sick is definitely a weird one though.

 

[Bernoull]

I think the correlation between temperature and "catching cold" has to do less with temperature per se and more with the aerosolization of particulates including viruses. So one a hot, damp day when someone sneezes, their viral particles will travel far less that they would on a cold dry day... I remember reading a study (yes someone studied and published on this very topic) i think on bbc health a while back where similar findings where reported...

And yes, mom's usually right...

 

[FutureDoc4]

Two reasons back that up that "ol'wise tale":

1) In cold weather there increased aersol transmission of orthomyxovirsues via aerosols:
http://www.ncbi.nlm.nih.gov/pubmed/18367530

2) Cold likely causes physiological stress (increasing cortisol, vasoconstricting, etc) which weakens the immune system and making you more susceptible to infection:
http://www.ncbi.nlm.nih.gov/pubmed/17705968

Because "transmission" is enhanced during winter months, staying warm, makes sure your immune system isn't "stressed" and you are not susceptible these infections that more easily spread.

P.S. Often, those "wise tales" are more right than we think... we just don't understand why, haha.

 

[swamprat]

Also I think lymphocytes work better at higher temperatures, hence one of the many reasons why you get a fever. Also I think more people get sick during the winter time because they are staying indoors on top of eachother.

 

[Knicks]

Two reasons back that up that "ol'wise tale":

1) In cold weather there increased aersol transmission of orthomyxovirsues via aerosols:
http://www.ncbi.nlm.nih.gov/pubmed/18367530

2) Cold likely causes physiological stress (increasing cortisol, vasoconstricting, etc) which weakens the immune system and making you more susceptible to infection:
http://www.ncbi.nlm.nih.gov/pubmed/17705968

Because "transmission" is enhanced during winter months, staying warm, makes sure your immune system isn't "stressed" and you are not susceptible these infections that more easily spread.

P.S. Often, those "wise tales" are more right than we think... we just don't understand why, haha.

👍

 

[myhandsarecold]

cold -> people stay indoors -> viruses gets passed around

viruses take a couple of days to incubate and start destroying to upper airway -> symptoms. it's more coincidental, infection probably took place a couple of days before it got really really cold, when everyone started to stay indoors more

 

[robu058]

cold -> people stay indoors -> viruses gets passed around

viruses take a couple of days to incubate and start destroying to upper airway -> symptoms. it's more coincidental, infection probably took place a couple of days before it got really really cold, when everyone started to stay indoors more

Just to add to what you are saying above: during the cold season, the virus spreads more because more people would stay indoor than outdoor...However, during the spring/summer, less people congregate indoor than outdoor (well, it is hot and humid inside, who would want to stay indoor)...So, if you have 1 pg of viruses, the incidence rate would be much higher during the winter season for the aforementioned reason than summer....

You could mitigate the transmission rate by constantly washing your hands and avoid people sneezing in your face since as people have said in this thread, the cold virus or rhinovirus is spread by aerosol!

 

[robu058]

Also I think lymphocytes work better at higher temperatures, hence one of the many reasons why you get a fever..

SAY WHAT!!!????!!!?!?!

Isn't true that all cell in the body regardless of the type work OPTIMALLY at 37C, our body temperature!!! Yes, if you are referring to bacteria, there are some that work best at 30C, others at 37C, 40C, or even 80C. But, we are not bacteria, my friend!!! If you think you are right, show me the articles, etc...

The reason you get a fever is to KILL bacteria and/or viruses that are susceptible to the change in the temperature, that is the ones, where their enzyme would be readily be denatured at such temperature!

 

[FutureDoc4]

Just to add to what you are saying above: during the cold season, the virus spreads more because more people would stay indoor than outdoor...However, during the spring/summer, less people congregate indoor than outdoor (well, it is hot and humid inside, who would want to stay indoor)...So, if you have 1 pg of viruses, the incidence rate would be much higher during the winter season for the aforementioned reason than summer....

You could mitigate the transmission rate by constantly washing your hands and avoid people sneezing in your face since as people have said in this thread, the cold virus or rhinovirus is spread by aerosol!

I am not so sure about this. If this was true (just being indoors), you would not see "seasonal" flux of orthomyxovirus infections and rhinovirus infections in the winter in "old people homes" (it would just be constantly high). They always have a higher incidence, but it is especially high (spike) in the winter. Yet, they are indoors most of the day and most of the year.

 

[sjdsn135]

I think it's more simple than that. I think when you don't wear a jacket or whatever, you have to expend more basal energy keeping your core temperature up, leaving less energy to spend on the function of your immune system. The result is a transient immuno suppression which allows already colonized pathogens (viruses) to start to grow out of control or get a head start on your immune system.

Obviously the cold air also paralyzes the mucociliary escalator, which doesn't help, but that happens even if you have a coat on.

I can't back any of this up, that is my theory.

 

[robu058]

I am not so sure about this. If this was true (just being indoors), you would not see "seasonal" flux of orthomyxovirus infections and rhinovirus infections in the winter in "old people homes" (it would just be constantly high). They always have a higher incidence, but it is especially high (spike) in the winter. Yet, they are indoors most of the day and most of the year.

Nah, son!!!

The reason why senior citizens are indoor most of the time, yet their rhinovirus infection rate is similar to any other age group trends, that is spike up in winter is SIMPLY because rhinovirus/flu (paramyxovirus/orthomyxovirus), unlike HIV, are seasonal viruses, they can ONLY be infectious ONCE, and after that you mounted an immunity to that particular viral strain, and more importantly the duration of the virus infection is very short (14 days at best). If you didn't have immunity to it and our body did not fight it, yes, the prevalence rate would have been higher and last LONGER, as you suggested.

Let me give an example! Suppose half of a population of a group (old people who live indoor) has been infected with, say a strain of rhinovirus, then it would take approximately 14 days for that half of the population to get better. Say, as they are getting better, the other half is acquiring the virus, thus it would take another 14 days for the other half to feel better. In total, it would take on average about 28 days for the entire population to acquire the virus and feeling better. These people would be protected from this strain of virus, and would never be infected from it, ever, or until next year when there is a brand new strain of virus! Thus, "[the infection rate in older population as you described above] would [NEVER] be constantly high."

This is fyi...Cold/flu infection usually starts in Asia around June...guess what season is it over there? Monsoon! Then, it travels around places where our summer is really their winter, places such as Australia come to mind. Then, it travels to US, and to other part of the World. For that season, the strain usually remains intact and this is why we are able to have flu vaccination (notice, the vaccination is usually available around end of october and that is because of that reason). Then, after the cold/flu season is over around the World, so is that strain of virus. Then, another strain surfaces due to genetic shift or drift, and the whole cycle begins anew!

 

[robu058]

I think it's more simple than that. I think when you don't wear a jacket or whatever, you have to expend more basal energy keeping your core temperature up, leaving less energy to spend on the function of your immune system. The result is a transient immuno suppression which allows already colonized pathogens (viruses) to start to grow out of control or get a head start on your immune system.

Obviously the cold air also paralyzes the mucociliary escalator, which doesn't help, but that happens even if you have a coat on.

I can't back any of this up, that is my theory.

Interesting, but the inverse should have also been true to consider valid IMO..that is...during summer time or Sub-Saharan desert residents should have been prone to infection because the body would invest so much energy to cool itself off. Thus, "The result is a transient immuno suppression which allows already colonized pathogens (viruses) to start to grow out of control or get a head start on your immune system."

NO?

 

[sjdsn135]

Interesting, but the inverse should have also been true to consider valid IMO..that is...during summer time or Sub-Saharan desert residents should have been prone to infection because the body would invest so much energy to cool itself off. Thus, "The result is a transient immuno suppression which allows already colonized pathogens (viruses) to start to grow out of control or get a head start on your immune system."

NO?

Ahhhh never thought of that good call. You are very astute.

My response to that (just to keep the conversation alive) would be that if you were overheated to the point where you felt like crap (like play soccer all day with a heat index over 100 degrees) you probably would have a higher chance of getting sick in the ensuing days as well. But I would explain that with a different self made-up mechanism:

Core temperature reaches like 100 degrees, cellular enzymatic processes become backlogged from non-ideal temperatures, heat shock proteins are expressed, total body cellular efficiency drops==> better chance of getting sick.

 

[robu058]

Ahhhh never thought of that good call. You are very astute.

My response to that (just to keep the conversation alive) would be that if you were overheated to the point where you felt like crap (like play soccer all day with a heat index over 100 degrees) you probably would have a higher chance of getting sick in the ensuing days as well. But I would explain that with a different self made-up mechanism:

Core temperature reaches like 100 degrees, cellular enzymatic processes become backlogged from non-ideal temperatures, heat shock proteins are expressed, total body cellular efficiency drops==> better chance of getting sick.

Again, nice theory! However, here is a caveat: viruses are not optimally infectious at said temperature for many reasons, and one of which is the effect of the heat on the viral enzymatic activities! The higher the temperature, the lower the viral enzymatic activities are, unless of course, you are a special breed of bacteria that thrives in hot temperature!

Thus, at these temperature both the host (us, human) and the pathogens are affected!

 

[ygree001]

Cold, dry air can irritate your nose and throat as well. It's not just actually getting a cold/flu, it's a general crappy feeling.

 

[Singh]

I gave this question a thought when I was student myself. It's quite interesting.
I have been taught that there is no strong evidence which shows that exposure to low temperatures causes a common cold, but more recently I have read that this is not necessarily the case. Here are my thoughts on this (can't be bothered to find the research on pubmed):

1. Constriction of arteries to the nose due to lower temperature reduces the efficiency of the immune defence in the nose. This eases entry of vira into the blood through the nose.

2. A universal weakening of the immune defence in the body (as others here have pointed out)

3. Staying inside in cold temperatures (partly explains the high prevalence of cold during the winter, but not why going out in the cold causes a cold - perhaps it's a co-incidence?)

4. Lower levels of D-vitamin during the winter period due to less sun exposure causes weaking of the immune system (fx. Th17 cells).

I personally believe that going out in the cold without a jacket INCREASES THE RISK of a common cold, but other factors (vira) are also required.

 

[robu058]

I gave this question a thought when I was student myself. It's quite interesting.
I have been taught that there is no strong evidence which shows that exposure to low temperatures causes a common cold, but more recently I have read that this is not necessarily the case. Here are my thoughts on this (can't be bothered to find the research on pubmed):

1. Constriction of arteries to the nose due to lower temperature reduces the efficiency of the immune defence in the nose. This eases entry of vira into the blood through the nose.

2. A universal weakening of the immune defence in the body (as others here have pointed out)

3. Staying inside in cold temperatures (partly explains the high prevalence of cold during the winter, but not why going out in the cold causes a cold - perhaps it's a co-incidence?)

4. Lower levels of D-vitamin during the winter period due to less sun exposure causes weaking of the immune system (fx. Th17 cells).

I personally believe that going out in the cold without a jacket INCREASES THE RISK of a common cold, but other factors (vira) are also required.

Excellent, excellent theory, Singh, especially to #1. It matches beautifully with everything I have been saying above!

 

[sunset823]

I only wear a jacket if it's less than 0 degrees Fahrenheit outside. And I have been the healthiest I've ever been (well, at least in terms of not having any infections). Attempting to build up that brown fat.