[_w1tm]

> It always catches me by surprise that you can get "a cold" in summer.

Despite the name you don’t get sick from cold weather but from viruses that make you sick. During cold season we stay indoors more which increases our likelihood of being exposed to other people that are sick.

[Anon4Now]

It's a phrase coined by Shakespeare in his play Cymbeline. As far as I know, it never had a basis in science but was a common belief.

During the Cold War, with the possibility of fighting in the USSR, the US Army conducted experiments with soldiers doing extended bivouacs outside in cold weather to see whether there was increased likelihood of sickness. They couldn't find any evidence that it did.

[2b3a51]

Plus one of the joys of teaching is the September two day cold. You suddenly encounter all of those nice new variants of the common cold virus.

I mention this as the grandparent comment talks about friends in teaching.

[kruffalon]

Well, I also got mine from someone working at summer camp :)

[watwut]

Your immune system underperforms when the body temperature goes down. It is not contact with people, the weather affects your immune system too.

> During cold season we stay indoors more which increases our likelihood of being exposed to other people that are sick.

For most people this is not really true nowdays. We work in the same offices and use the same kind of transport when going to the office. We shop in the same stores.

The seasonal lifestyle change is fairly miniscule.

[mathgeek]

> It is not contact with people, the weather affects your immune system too.

Did you mean not _just_ contact with people? Many folks who isolated during covid saw a reduction in illnesses regardless of season.

[watwut]

Yeah, I meant just.

[ajuc]

There's new research that infrared radiation (mostly experienced when it's sunny and you're outside) helps mitochondrial function and boosts the immune system.

So there's at least 4 mechanisms:

- warmer = less likely to catch a cold

- more time outside = more UV which kills pathogens

- more time outside = less time spent exchanging pathogens with other people

- more time outside = more infrared radiation which boosts the immune system

[kruffalon]

Hmm, that's interesting, I thought the causality is that when you're cold your body is busy generating heat so is worse at fighting of infections.

[taneq]

I think it’s more just that you’re inside a lot with other people, easing transmission.

[type0]

that and less humidity in the indoor air, sedentary work doesn't help either, less blood-flow and it's harder for lymphocytes to fight off infections