Wet Hair & Colds: Fact vs. Fiction | Expert Advice

Debunking the Myth: Does Sleeping With Wet Hair Cause Colds or Flu?

A persistent belief that sleeping with damp hair can lead to illness has been challenged by medical experts, who emphasize that viruses – not temperature – are the root cause of colds and the flu. As winter approaches and concerns about respiratory illnesses rise, understanding the true factors behind infection is crucial for effective prevention.

Many long-held assumptions about how we contract colds and influenza influence our behavior, but not all are grounded in scientific evidence. One of the most enduring myths centers around the idea that going to bed with wet hair increases your risk of developing a respiratory infection.

The Science Behind the Myth

Contrary to popular belief passed down through generations, an infectious disease doctor and clinical pathologist, Celso Granato, asserts that colds and the flu are exclusively caused by viruses. “The flu or a cold only develops in the presence of a virus,” Granato explained. “Wet hair does not directly influence these viral infections.”

However, Granato cautions that damp hair can create a more favorable environment for the growth of fungi and bacteria on the scalp. “Our skin is full of bacteria, but with wet hair you create an even more welcoming environment for them. Then it has a chance of becoming a respiratory problem,” he stated, adding that he is a member of the Brazilian Society of Clinical Pathology and Laboratory Medicine (SBPC/ML).

The origin of the myth, according to Granato, likely stems from coincidental timing. Individuals already in the incubation period of a cold – often caused by the rhinovirus – or the flu – caused by the influenza virus – may have washed their hair before bed and then developed symptoms a few days later. “In this case, the person would have the disease with wet or dry hair,” the specialist observed.

Strengthening Your Winter Defenses

While wet hair isn’t a direct cause of illness, bolstering your immune system is paramount during the colder months. Granato emphasizes the importance of a balanced diet rich in proteins, fruits, legumes, and vegetables.

“When you have a diet with a little bit of everything, your immune system is ready to react to any infection,” he said. Equally vital is staying current with your vaccination schedule, particularly for the flu. “People have to be vaccinated annually against influenza (which causes the flu), because the effect of the vaccine weakens over time,” Granato highlighted.

Furthermore, adopting preventative measures like wearing masks indoors can significantly reduce the risk of viral transmission. The medical community observed a dramatic decrease in cases of the flu and common colds during the pandemic, largely attributed to widespread mask usage. “Therefore, we must wear a mask to protect ourselves, and if you are sick, to protect others,” Granato recommends.