Uncovering the Truth: Why Do We Get Sick in Cold Weather?

[WarrickF]

A friend of mine were discussing the cold weather and how everyone's getting sick. I was then trying to figure out why exactly people to tend to get sick when it gets cold? I'm sure there some very logical explanation, but I could not for the life of me think what it was.

Everyone knows your mom tells you not to go outside with wet hair when it's cold out, or you'll get sick – but why is that?

 

[scott1]

Probally because your body tempture gets colder so it's for virus attack the body

 

[HallsofIvy]

Probally because your body tempture gets colder so it's for virus attack the body

I don't know about you but I'm warm blooded! My body temperature is always fairly close to 98.6.

However, your body has to work hard to stay at that temperature and the colder, wetter, etc. the environment is the harder your body has to work. It's when your body is stressed that it has a harder time fighting of any disease germs. Cold germs, especially, are "everywhere". It is not a matter of if a cold virus gets into your body you will catch a disease. There a probably a lot of cold viruses in your body right now. It's just if your body is having to do much to keep you warm and doesn't have enough resources to fight off those cold viruses that will dtermine if you get a cold or not.

 

[scott_alexsk]

I not sure this is what your question was asking but I'll tell anyways. For the most part in cold weather, people stay inside. This incubates diseases allowing them to spread quickly within a household. Its a combination of things in cold weather, but this is part of it.
-Scott

 

[WarrickF]

Ya I guess that makes sense, but I guess I was interested to see if there had ever been any real studies done on the topic. I know there are some things that just make sense and are not worth researching, but considering I have a cold and there's no easy way to kick it, it seemed like a good question.

Seems odd, that something as common as the "common cold" is still such a pain in the xxx.

My thinking is that your body, during this season has more than enough energy to fight off germs (considering all I've done is eat for 4 days now )

 

[Moonbear]

I not sure this is what your question was asking but I'll tell anyways. For the most part in cold weather, people stay inside. This incubates diseases allowing them to spread quickly within a household. Its a combination of things in cold weather, but this is part of it.
-Scott

This really is the biggest part of it. More people are indoors and crowded together, plus there are a bunch of winter holidays that bring people together who don't see each other often, so while you probably have immunity to all your "local bugs", you get exposed to new ones during those holiday gatherings, not to mention standing in those long lines at the mall while people are doing Christmas shopping!

There's also some evidence in the literature that at least in some species (not really studied much in humans) that there are seasonal changes in immune system function.

Something else that occurred to me as I was writing this is that the air is also drier, so possibly that contributes to weakened defenses. One of those first lines of defense against invading germs is the mucus in your nose, and isn't working as well because your nasal passages are drier in winter than during the summer. Plus, when your sinuses get dry, they get more irritated, and there are more small tears in the epithelial layer that allow the germs to slip in. (Ever notice how the air gets dry and people have trouble with nosebleeds? That's what I'm referring to.)

 

[matthyaouw]

I heard recently of a study which found that simply being cold can increase your susceptibility to disease. Constriction of the blood vessels in the nasal passage makes it easier for microbes to take hold. I don't remember any specifics given in the article though.

 

[scott_alexsk]

They were talking about this in another thread in this forum. Do you guys have any idea at what body temperature the body can no longer effectively warm itself. They were trying to create an equation calculating the amount of calories you lose if you stand are in a cold enviorment. I mentioned that the body can proably only counteract the cold at a set rate (since people freeze to death before they starve).
-Scott

 

[russ_watters]

There are too many variables to calculate how cold the surroundings can be before you can no longer maintain body temperature. Everything from how much clothing you are wearing to how fat you are to what kind of shape you are in makes a big difference.

 

[ecoli]

There's no evidence that cold directly causes disease. But cold influences your stress levels which definitely influences your immune system. It could also be that during the winter months stress level goes up for reasons other then cold.

 

[-Job-]

It's interesting that the cold factor seems to induce viral diseases more than bacterial ones. Perhaps at any given moment viral dna for cold/flu is merged in many cells' nucleous. If the viral dna is situated near the dna coding the instructions for reacting to a temperature drop then at low temperatures cells reach for the infected dna which leads to the production of viral proteins and consequent assembly of the virii.
It has occurred to me, and excuse me if this sounds ridiculous, that the DNA that produces certain viruses might not be foreign at all, meaning it has not been introduced to the organism but exists from birth. I can imagine that in normal cell metabolism, under necessary conditions, a given cell might assemble a virus inadvertently. Spontaneous contraction of a disease.

 

[Evo]

Something else that occurred to me as I was writing this is that the air is also drier, so possibly that contributes to weakened defenses. One of those first lines of defense against invading germs is the mucus in your nose, and isn't working as well because your nasal passages are drier in winter than during the summer. Plus, when your sinuses get dry, they get more irritated, and there are more small tears in the epithelial layer that allow the germs to slip in.

I've also read papers that back this up.

I'm sure getting wet/chilled and causing stress to the body, followed up by lots of dry heat to warm up would be a double whammy.

 

[matthyaouw]

Found the article!
http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20051113/Commoncold_051113/20051113?hub=CTVNewsAt11

 

[cotarded]

Did nobody see -Job-'s very interesting conjecture?
http://en.wikipedia.org/wiki/Lysogenic
This reaffirms what you said, and what I remembered: That adrenaline and the stress response can be lytic triggers for latent viruses. I'll be checking around to see if any lysogenic viruses are involved in nasopharyngitis.
While I don't personally buy that this subserves the chill/wet trigger, as most of the transmission research I've read during my extensive ;) study in the last 15 minutes claims only a 2-3 day incubation, it seems far too interesting a conjecture not to explore at least a little bit.

lates,
cotarded

 

[Reality_Patrol]

...There's also some evidence in the literature that at least in some species (not really studied much in humans) that there are seasonal changes in immune system function.

I think that's the primary reason. Biologists are almost prudish about admitting the possibility of human seasonality. Yet mammalian seasonality is well established. Does this perhaps reveal a bias, that biologists are secretly reluctant to view humans as nothing more than another species of mammalian life?
By the way I've discussed this topic before and it usually stirs a heated debate. I don't plan too get any more involved this time. I will only state if you're really interested you can do some internet research on Google's "scholar" page. Search on "photoperiodism"...

 

[Moonbear]

I think that's the primary reason. Biologists are almost prudish about admitting the possibility of human seasonality. Yet mammalian seasonality is well established. Does this perhaps reveal a bias, that biologists are secretly reluctant to view humans as nothing more than another species of mammalian life?
By the way I've discussed this topic before and it usually stirs a heated debate. I don't plan too get any more involved this time. I will only state if you're really interested you can do some internet research on Google's "scholar" page. Search on "photoperiodism"...

I guess you haven't discussed the topic here before. You're actualy preaching to the choir here. I AM one of the people who works on NIH-funded projects on seasonality, and every time a grant is submitted by myself or one of my colleagues, we need to spend a good deal of effort explaining why we should be studying a seasonal mammal, and why it should be relevant to humans. One problem we face is that there are quite a few "crackpot" type articles out on human seasonality that detract from the credibility of the more solid science. It's also difficult to sort out seasonal trends based on cultural practices from underlying seasonal rhythms with a biological basis, and because we live in artificial environments...electric lights, air-conditioning and heating to keep temperatures fairly consistent from winter to summer, clothing to help us adapt to outdoor temperature changes, etc., it may be very difficult to identify photoperiodism in humans if it's really there. There isn't a lot of clear-cut evidence that humans are seasonal, but rather, when seasonality does present itself in a human, it's often counter-productive to cultural expectations and labeled a disorder (such as seasonal affective disorder).

Anyway...this really is a subject for a different topic than the one in this thread. I'm always happy to discuss seasonality.

 

[Burnsys]

I heard that when it's cold, people only eat Warm meals, avoiding Cold meals.
Warm meals loss a lot of nutrients in the proses of cooking while cold meals maintains it all...

 

[Moonbear]

I heard that when it's cold, people only eat Warm meals, avoiding Cold meals.
Warm meals loss a lot of nutrients in the proses of cooking while cold meals maintains it all...

Where did you hear this? Other than winter carbohydrate cravings reported by those with Seasonal Affective Disorder, I don't know of anything that would suggest we eat differently in winter than summer. I don't know about you, but I cook most of my food year round, and the stuff I munch on raw (I assume that's what you mean by cold, and not things like ice cream), I still munch on in the winter. Perhaps the foods we eat in summer are fresher, at least fruits and vegetables, so haven't lost as many nutrients in storage before reaching the table, but that has nothing to do with it being hot or cold.