Recent scientific studies have revealed that cold weather is not a direct cause of colds or influenza, contrary to popular belief, but it creates biological and environmental conditions that contribute to increasing the spread of respiratory diseases during the winter.
The research, published on The Conversation scientific platform, showed that viruses are the real cause of respiratory diseases, not exposure to cold itself.
These viruses include influenza viruses and rhinoviruses that cause the common cold, which are transmitted between people through respiratory droplets or direct contact, regardless of the outside temperature.
Despite this, rates of respiratory diseases increase significantly during the winter in various regions of the world, which scientists link to the effect of cold and low humidity on the survival and spread of viruses.
Studies indicate that viruses live longer in cold and dry environments, and remain capable of causing infection compared to warm and humid conditions.
Dry air plays an important role in increasing transmission of infection, as it leads to the rapid evaporation of small droplets resulting from coughing, sneezing, or talking, which turns them into finer particles that remain suspended in the air for a longer period, thus increasing the chances of others inhaling them.
Inhaling cold air also affects the body’s natural defenses, as it lowers the temperature inside the nose and respiratory tract, causing blood vessels to constrict and reduce blood flow.
This weakens the local immune response that normally prevents viruses from causing infection in its early stages.
In addition to biological factors, behavioral changes in the winter contribute to exacerbating the problem, as people tend to spend more time indoors with limited ventilation, which increases the chances of transmitting viruses, especially in crowded places.
In addition, there is a decrease in exposure to sunlight during the winter, which leads to a decrease in levels of vitamin D in the body, which is an essential element in supporting the functions of the immune system.
Indoor heating systems also dry out the air, reducing the effectiveness of mucus that traps viruses and expels them from the respiratory system.
The researchers stressed that scientific evidence does not support the idea that going out without a coat or feeling cold directly causes illness. Rather, cold weather acts as a risk multiplier by creating an environment suitable for the spread of viruses and weakening the body’s defenses.
Experts called for focusing on effective prevention, such as improving indoor ventilation, maintaining appropriate humidity levels, and supporting immune health, instead of entrenching misconceptions about the relationship between cold and disease.
