: Why do cold temperatures cause a weaker immune system/make it easier to get sick?



I don’t know if it actually causes a weaker immune system, I just assumed it did. Otherwise the title says it all.

I could add for example why is leaving home early in the morning with wet hair, when it’s cold outside, considered not good because you could get sick.

In: Biology

It takes energy for you body to warm itself, taking energy away from immune system functions.

It’s a superstition that persists today. The ambient weather has nothing to do with your health. The reason we came to associate cold and flu with the cold weather is that the weather creates extremely hospitable conditions for their spread. It’s the reason flu season overlaps with the fall/winter months.

In the winter, humans tend to gather indoors in close proximity, sharing air and personal space. The cold, dry air also allows airborne viruses and pathogens to survive and remain infectious much longer outside the body. Because we observed this phenomenon long before microbiology could explain it, we came to ascribe these diseases to the cold weather itself, not the pathogens we spread.

It’s not the cold per say, it’s what it makes us do: stay indoors crowded with others. This increases transmission. A lack of sunlight in the winter months and being inside causes various levels of vitamin D deficiency for many people, making them be more susceptible to getting sick.