Health

Dormir com Cabelo Molhado Causa Gripe? Especialista Explica o Mito

by Olivia Martinez - Health Editor
written by Olivia Martinez - Health Editor 0 comments

As winter illnesses begin to circulate,long-held beliefs about how to avoid colds and the flu often resurface. A common concern, especially in Brazil, is whether going to bed wiht wet hair can increase your risk of getting sick. Despite its prevalence, medical experts confirm this is a myth-colds and the flu are caused by viruses, not by temperature or moisture-though damp hair can present other, secondary health concerns.

By Staff Writer | January 3, 2026

This popular belief has persisted for years in the Brazilian imagination, but does not correspond to scientific facts. (Photo: Freepik)

As winter arrives, many popular beliefs about actions that could lead to a cold or the flu influence our behavior. However, not all of these beliefs have a valid scientific explanation or are supported by expert opinion. One of the most well-known is the idea that sleeping with wet hair can increase your risk of developing these illnesses.

Does wet hair actually lead to a cold or the flu?

Contrary to what many parents and grandparents claim, this is a myth. According to infectious disease specialist and clinical pathologist Celso Granato, the flu or a cold only develops in the presence of a virus. In other words, wet hair does not directly influence these viral infections. Understanding the true causes of illness is crucial for effective prevention.

However, an unintended consequence could be the encouragement of fungal and bacterial growth in the hair.

“Our skin is full of bacteria, but with wet hair you create an even more welcoming environment for them. That’s when there’s a chance it could become a respiratory problem,” explains Granato, who is a member of the Brazilian Society of Clinical Pathology and Laboratory Medicine (SBPC/ML).

The specialist suggests the origin of the myth may stem from instances where someone was already in the incubation period of a cold (most often caused by rhinovirus) or the flu (caused by the influenza virus), went to bed shortly after washing their hair, and then became ill two or three days later.

“In that case, the person would have the illness whether their hair was wet or dry,” the infectious disease specialist observes.

To protect yourself during the winter, Granato points out that the most effective approach is to maintain a balanced diet rich in protein, fruits, vegetables, and legumes. Staying up-to-date on vaccinations, especially the flu vaccine, is also essential.

“When you eat a diet with a little of everything, your immune system is ready to react to any infection. Another important thing is to get vaccinated regularly. People need to get vaccinated annually against influenza (the cause of the flu), because the effect of the vaccine weakens over time,” the doctor emphasized.

In addition, measures such as wearing masks in enclosed spaces can also minimize the chances of developing a viral infection.

“The medical community noticed that during the pandemic, other viruses practically disappeared. We went through those years seeing almost no cases of the flu or colds due to mask use. Therefore, we should wear a mask to protect ourselves, and if we are sick, to protect others,” he recommends. (With information from the newspaper O Globo)