> 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.
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.
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.
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
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.