Why Do People Seem To Get More Colds In The Winter?


There
are two aspects to this question. The first
is temperature. Numerous studies throughout the last century have shown that cold temperatures
will not increase your chance of becoming infected by a cold virus. Now that’s out
of the way, let’s attack the second aspect. The fact that there is a “cold and flu season”,
and it does coincide with cooler temperatures. The analytical side of me needs to break through
some societal tendencies before this second aspect can be evaluated. From my experience,
when people get sick, they tend to describe mild symptoms as “colds” and severe ones
as “the flu”. Unfortunately, you can’t diagnose an illness simply by the perceived
severity of symptoms. If any given group of people were exposed to the same cold virus,
many would have mild to no symptoms, and some would have more severe reactions. The same
can be said for flu viruses. The distinction between the two also gets blurred by some
people’s tendency to over-exaggerate their symptoms. In truth, a person’s reaction
to them aside, these are two very different types of viruses. There are over 200 different strains of “cold”
viruses, mainly made up of rhinoviruses (up to 50%). The average adult in the US will
get 2-4 colds per year. The average child will get 6-8. These types of viruses usually
are associated with mild symptoms. Up to 25% of infected people won’t show any symptoms
at all. Most won’t get a fever, and if you do, it will be low-grade- around 100 degrees
Fahrenheit. Your Runny nose (thus rhinovirus) and cough will tend to be mild. These viruses
primarily won’t transmit through the air. Instead, people become infected by coming
into direct contact with someone who has an infection, or touch something that an infected
person touches. Influenza, however, is a much more sinister
beast, affecting approximately 10% of the US population every year. This virus tends
to start with sudden onset of a higher fever between 100-104 degrees Fahrenheit. It then
progresses into chills, headache, muscle aches and a loss of appetite. Flu’s can also lead
to more serious conditions like bronchitis and pneumonia. Those whose immune systems
might be compromised, like the elderly or chronically ill, are at risk of death. Approximately
20,000 people a year die from the flu, so maybe mom was right. You will catch your death! So why the increase in these illnesses in
the winter? It seems this knowledge has been around for many centuries. The word influenza
comes from an older Italian phrase “influenza di freddo” or “influence of the cold”.
The flu-season usually ranges from November to March in the northern hemisphere (the coldest
months) and May to September in the lower. In fact, in tropical climates, there tends
to be extremely low incidences of flu and certainly no true “flu season”. There are several contributing factors to
why cold temperatures increase influenza infection rates, all of which seem to be well known
and promoted by health officials in numerous publications. The most common is that people
tend to stay indoors when the temperatures get colder. This allows people to be in closer
contact with each other and therefore makes it easier to pass the virus from person to
person. Another contributing factor could be that in large parts of the country children
are going back to school and interacting more with their fellow infected. In fact, most
epidemics can be traced back to children. The answer to this riddle lies in how the
influenza virus reacts to temperature and humidity. The virus is extremely stable in
colder temperatures, 41 degrees Fahrenheit optimally. The warmer you go, the less stable
it becomes. Around 86 degrees, the virus isn’t transmitted at all. Humidity also plays a very important role.
Influenza is primarily transmitted on the droplets from your respiratory tract (cover
your mouth when you cough kids!) The more humid the environment, the more water is available
for those droplets to “pick up”. The heavier the droplets become, the faster they will
fall to the ground and out of the way of our mucus membranes. In drier environments, those
death droplets hang around in the air longer for others to breathe in. In fact, one study
showed that the virus was best transmitted at a humidity of 20% and not transmitted at
all once the humidity reached 80%. (And you thought moving to more tropical climates when
you get old and sick was just a bunch of voodoo medicine!) That same study showed animals transmit the
virus for a full two days longer at 41 degrees F than they do at a room temperature of 68.
The conclusion was that a person’s respiratory tract is colder and therefore the virus can
be more stable inside your mucus membranes. So what does all this mean? You are no more
likely to get a cold in the winter then you are in the summer. The flu, however, is a
different animal altogether. You are more likely to get this virus in the winter. So
just remember kids: wash your hands, cover your mouth when you cough, and apparently
move to Florida when you retire.

52 thoughts on “Why Do People Seem To Get More Colds In The Winter?

  1. Ha! My PhD-thesis was about specific Rhinovirus-Strains. Also worked with Polio, as a control.

    Thanks for spreading this important knowledge!

  2. My Dad is doing research into this and he says that the "numerous studies throughout the last century" were really badly done and they essentially kept sourcing the virus from the previous people in the study, effectively changing the virus under examination to be too different from the wild virus to be valid.

  3. Surely it has to do with vitamin D depletion.. By the time we get into November we've used up our entire store of vitamin D that we got from the sun in the summer.. As vitamin D is necessary for a robust immune system then this means that we don't cope very well with viruses in the winter time when we're not making vitamin D due to low UVB intensity.. Whereas, if you lived in Florida as you say then you'd be making vitamin D all year round.. I'm surprised that you didn't mention this as it is a well established medical explanation for the "flu season"..

  4. I rarely get colds, while i watch and laugh as my friends and family get their colds maybe i just have the worlds greatest immune system.

  5. I've observed a correlation with the Flu season peaking right after people start turning on their Furnaces. While one might say, but of course, that's because it signals the beginning of the cold weather. However, I suggest that it's possible that pollen and other detritus, bacteria, and virus' collect in the air conditioning ducts during the summer (this would be especially true if Flu bugs like it colder) Then, when people turn on the furnace, warm air blowing not only dislodges the pollen, detritus, bacteria and virii; but makes it easier for them to become airborne as they dry out from the warmth, lower humidity, and there you have it. A sudden deluge of all the 'stuff' having accumulated in your cooler air ducts during the summer months suddenly assails our bodies in massive amounts making us sick. Naturally, pollen due to allergies can reduce our resistance to infections; top that with any other allergens, add bacteria causing infections, and you have a ready ripe ground and body for catching and delivering the Flu to a ripe and ready host!

    I've been monitoring this since I was a young adult, and I'm now 62. Knowing this, my wife and I will now generally run the furnace and take a day away from home, then return to air it out, then go out for dinner. Since we have been doing this… my wife who has been plagued with allergies, colds and of course 'the flu' since we married 40 years ago has had nary a case for over 6 years, and when she does (2x), it is only a cold, and very mild. Food for thought.

  6. Knew the public health department here on Guam @ 13 degrees north of the Equator, but who follow federal guidelines issued by the NIH & the CDC, insist on everyone getting an influenza vaccination every year when the average daily temperature is 88 Fahrenheit with 80% humidity. Knew it was bullshit from the git & that going to the clinics overflowing with sick kids to get the shit was more likely to kill you than getting an extremely unlikely "flu" in this unincorporated territory of The United States.

  7. Your missing one of the reasons, that is temperature shock. Rapidly going from hot to cold has shown a number of good and bad effects. May want to mention that later.
    One source:
    http://www.wsj.com/articles/SB10001424127887324139404579015062305117896

    But there are many more.

  8. That is what they said about H1N1 or the Swine flu back in 2009. They said it started in a small town in Mexico from a child that was around swine. Some how the virus crossed over from beast to boy. And then from him, it spread to the entire world. Not to mention there was the seasonal flu onto of the H1N1. 3:20

  9. I believe another big contributor is that when you get cold (not "a cold", but being at a low temperature from a cold environment), your nose runs. You wipe it with your hand, then rub it on your pants, but not all of the germs rub off … then you touch everything else in your environment that everyone else is also touching. So, even if you're not feeling the symptoms of a cold, simply because you've become cold, it greatly increases your likelihood to spread it to others with your runny nose.

  10. Another factor though unproven is the lack of Vitamin D production in the winter. Anyway I haven't had a serious flu in years and I attribute that to neti potting whenever I might have been exposed to the virus and taking VitD at 1000iu at least once a week. I did get influenza A two winters ago but the symptoms were those of a mild cold (I have asthma btw), for the heck of it had my wife (a GP) take a swab and it tested positive for the above. Again, neti pot and VitD.

  11. I saw something about 18 months ago that showed how colds are primarily transmitted across surfaces, and how they mostly enter your body through a tear duct…I have since been fastidious about how and when I touch my eyes, so therefore it must be no coincidence that everyone around me gets colds, yet I remain unaffected! I unfortunately suffer "cold sores" on the odd occasion, but this is a different beast – so would be interested in any video you could do on those, please…? Thanks in anticipation x

  12. love the vids simon
    but i dont understand the picture that was at the beginning of trhe video
    how does the picture of the veiny eye relate to colds, is that how the eyes look when u have a cold
    thanks for the vids

  13. Based on what you said about the flu stuff, it seems we still should bundle up in the winter, not because it will prevent us from catching our death, but to be considerate and not give someone else theirs. 🙂

    Also, what is with this new trend of people using "over-exaggerating" when by context it's apparent they just mean "exaggerating?" It grates on me more than non-literal "literally"s.

  14. I can't remember where I read about this hypothesis, but I gather that there was at least one study that tends to support it: One reason people get more colds in the winter is the confluence of three factors: First, they are rhinoviruses – they incubate in our noses. Second, converse to the fact that a fever kills off these sorts of viruses, somewhat cooler temperatures allow these viruses to breed better. Third, in the winter, we breath cold air into our noses, which produces cooler temperatures in our noses.

  15. There is also another reason for the cold and flu season. Vitamin D (specifically the active form 1, 25-(OH)2 D3) plays a critical role in immune cell signaling pathways. Vitamin D3 is rarely found in the diet and is generally synthesized in the skin when exposed to sufficient amounts of UVB radiation. People living above 30 degrees North latitude for example, can not synthesize D3 in the winter months as virtually no UVB radiation gets though the ozone at that time. Even if all of their skin was exposed they simply can not make the vitamin. People living in these areas tend to be vitamin D3 deficient (80% of the population) which makes a strong correlation with the increase in colds.

  16. You get often cold in winter, because there's less sunlight and your body can't produce enough vitamin d. The immune system is then weaker, than in summer.

  17. Hurricanes, alligators, sharks, malaria and people with lots and lots of guns; moving to Florida is just plain bad advice. Take your chances with a good ol' Canadian winter and survive a long and prosperous life!

  18. The real reason for the flu season is the Pharmaceutical companies pass out flu shots every year which contains a small amount of the virus so the antibodies build a tolerance to that strain of flu. What they don't tell you is that when you get a shot you are now a carrier for a short period of time. Everyone you come in contact with who has not been immunized will become infected. It's pure genius financially. Especially when they require health officials to get the shot.

  19. Ready to learn more cool facts? Then check out this video and find out the answer to the question- Why Do Peppers Taste Hot and Mint Taste Cold?:
    https://www.youtube.com/watch?v=wltCVLdkYys

  20. he forgot to add that birds carry around 90% of the new flu viruses and in the winter they fly cross county exposing people to viruses they never had before so we all get sick!

  21. I usually get a cold I can feel, when the weather can't decide if it's going to be hot or cold. So you either wear too much or too little clothes and it is impossible to find middle ground. xD

  22. Lived in Florida for 7 yrs, got sick 1 time (ear infection)… moved back to PA for 3 yrs now… sick at least 10 times… -_-

  23. cover your mouth when you cough and be polite and shake hands when greeting someone whohasnt been exposed to the flu. lololol

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