[mickrussom]

My wife always bugs me about the cold. I tell her operating rooms are cold. Heat = entropy, disease vector increase. Any thawing of permafrost will start to revive dormant diseases, viruses and flora. We might as well complete the trifecta and start looking for ancient DNA and revive long gone species for the win. She always tells me cold and drafts = sick, but if you look where the percent of currently diseased - its never in the north - always in tropical places where diseases, worms, parasites have a field day. There will be a day where she'll be begging for the cold :)

[exhilaration]

I've read that cold operating rooms are cold for the comfort of the surgeons, but the cold leads to more infections and slower recoveries: http://www.nytimes.com/1997/04/16/us/surgery-s-chill-can-be-...

Here's a more recent article that cites some papers: https://www.verywell.com/are-operating-rooms-cold-to-prevent...

[derefr]

Makes sense to me. A lot of bodily fluids sit right on the line between "gel" and "liquid" at room temperature. And gels promote biofilm formation. A few degrees too cool and all your externally-exposed fluids are now gels all the time.

Thus half the reason for saunas (besides the Heat Shock Protein effects): they turn all the gels caught in your pores, your sinuses, your tonsils, your lungs, etc. to liquid, where your body can then much more easily flush them out.

Though, freezing cold air isn't that bad, either: a lot of those liquids will become fully solid. Frozen snot grows no bacteria.

I guess it's just the "danger zone" principle of food safety, applied to human tissue?

[hinkley]

I believe they figured out that there is some truth to the idea that cold=sick at least for influenza. It doesn't live long while airborne but in a cold environment it can survive a bit longer, meaning in a warm room if someone sneezes you are less likely to be exposed than in a cold one.

[Asooka]

Doesn't the cold also suppress your immune system, since you're using up calories to warm your body?

[richcollins]

Cold is correlated with low sunlight, which leads to less vitamin D production:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4463890/

[knicholes]

I read that being in a cold environment weakens the immune response in your nostrils when breathing in that cold air enough to cool off the inside of your nose, where then the pathogen fails to be destroyed as it would have normally had it not been cold.

[dkersten]

I recently saw an article on HN (don't have a link, sorry) that said that cold did not, in fact, do anything to make us sick or help us catch stuff[1], EXCEPT that it made it more likely to spread something due to running nose or other contact with body fluids.

[1] it may have been specifically about cold and flu, I don't remember exactly. It was within the past month or two in case you feel like searching...

[hinkley]

Air circulation is compromised in the winter because we close all the windows and doors, and generally we congregate closer together.

For a long time that was considered to be the only reason colds happen more in cold weather. This thing with influenza viability would change that (of course, what one study finds another refutes, so who really knows).

[nkozyra]

Here in Florida no circulation season is April - November. And yet flu season is still winter, the only part of the year where people even consider opening windows.

[flamedoge]

Doesn't it go both ways? doesn't cold make bacterias weak?

[abandonliberty]

Influenza is caused by a virus, and viruses tend to be extremely resilient. They're not alive so temperature changes don't affect internal chemical reactions as it would for bacteria and humans.

Bacteria have temperatures at which they grow most effectively, which is why we try to keep food cold. Note that the food in your fridge still goes bad, and it would be pretty damn uncomfortable living at fridge temperature for humans. Bacteria are way more resilient than we are, though it varies by species.

Generally the answer is no.

[Fomite]

> Influenza is caused by a virus, and viruses tend to be extremely resilient.

Viruses can be extremely resilient or extremely fragile, depending on a number of factors including whether or not they're enveloped, whether or not they're currently protected in an aerosolized droplet, etc.

[taneq]

> They're not alive [...]

This is basically the biology version of 'vim is better than emacs'. :P

[drKarl]

But vim IS better than emacs

[thesmallestcat]

Humidity is a factor also. In drier conditions, nostril hair and mucus are less effective filters.

[Iv]

The main causal link I have seen between common cold and temperature is that some common cold virus develop in the nasal cavity but need a temperature closer to 30 degrees than our typical body temperature to prosper.

[AckSyn]

The takeaway I get from this is we're in for more than a little warm weather when it comes to "global warming"