Cold weather doesn't cause colds: debate divides experts and internet

Cold weather doesn't cause colds: science says so, your grandmother disagrees

Cold weather itself does not give you a cold. This is the conclusion that science communicators repeat every winter, which predictably triggers online outrage. The last time someone stated this clearly, the reaction was familiar: claims that bicho don't exist, bacteria are to blame, or cold water destroys immunity. Far from being settled, the discussion has become as predictable as January sales.

The trigger was a video in which a young man, with premature grey hair and dressed like a popularizer, explained that being at five degrees, wearing wet socks, or sweating through a shirt will not give you a cold. The response was immediate: ranging from those wishing him exemplary hypothermia to those accusing him of being a pharma shill. The tone, as seen, did not invite nuance.

Why doesn't cold weather cause colds?

The physiological explanation is simple yet uncomfortable for common sense. Cold weather does not create bicho out of thin air. What it does is lower local defenses: it reduces blood flow in the respiratory tract, dries out mucous membranes acting as barriers, and alters the lipoprotein layer of some bicho, making them more effective at infecting. In other words, cold weather is not the agent, but an accomplice.

This nuance is lost in the argument. Some maintain that cold weather per se does not cause illness and that everything else is folklore. Opposing this is the widespread street view: if you get cold, you catch a cold. In between, a handful of participants try to explain that the human body harbors latent bicho and bacteria that only need an opportunity. That window is peine precisely by cold weather.

The discussion quickly drifted into murkier territory. There were those who denied the existence of bicho, those who claimed everything was bacteria and fungi, and those who saw global conspiracies in every vaccination campaign. It is the background noise accompanying any health conversation in recent years. And, as always, it obscures the interesting data.

The bar experiment and the drink

One of the most cited fragments of the debate was a home experiment described in detail by several participants. The idea was leaving a bar in January, wearing a t-shirt, holding a cold glass, alternating between coat and street, and checking if one proge up with a runny nose the next day. The result, according to those who tried it, was unanimous: you get sick. It makes no difference whether you are alone or accompanied.

Some concluded that bicho do not exist. Science, however, concluded that repeated cooling and prolonged exposure weaken the immune response. An exotic pathogen is not needed: it suffices that the ones already present find fertile ground. This is the difference between a hypothesis and a certainty, and in this case, certainty does not support the hypothesis.

Another recurring argument involved Nordic countries. It was said that in Sweden or Norway, babies nap outdoors in sub-zero temperatures. This is true, but with nuances noted in the debate: they are heavily bundled up, only for short periods during the day, never at night, and always under adult supervision. The custom does not prove cold weather is harmless, but rather that the human body adapts to what is thrown at it with appropriate clothing.

Cold showers, offices, and other theories

Some recounted taking ice-cold showers for years without remembering their last cold. Others pointed to the office as the true contagion hotspot: open-plan rooms with two hundred people, colleagues coming to work coughing because they don't stay home, and an infection calendar predictable three days in advance. The anecdote, though seemingly minor, points to something the debate fails to close: cold weather is not the only factor, nor likely the main one.

Also appeared the theory that extreme heat is more lethal than cold, citing examples of people living in warm zones reaching a hundred years old. And the opposite: that dry cold is used in cryotherapy and that it is damp cold that causes illness. Everyone pulled the firewood toward their own side, as is customary.

The pharmacy business

One of the most repeated accusations concerned commercial interest. It was said that those debunking the cold myth often have a pharmacy behind them and that if they don't sell cold remedies, they don't eat. It is an old argument difficult to refute without getting muddy, but it is worth remembering that recommending bundling up, staying hydrated, and sleeping well is not exactly a goldmine for the industry. Another matter is that the industry exists and sells.

What became clear is that the debate is less about medicine and more about trust. Who we believe, whom we listen to, and what we are willing to accept when evidence contradicts what we were taught at home. Cold weather doesn't cause colds, but the habit of blaming it is stronger than any study.

With these elements, it is predictable that next winter will bring the same mantra, the same arguments, and the same wet socks. And that no one will agree. The prediction, however, comes with reservations: science advances, but common sense moves slower.