With the arrival of fall, we often notice an increase in respiratory illnesses, such as colds, flu, or viral infections.
Several factors converge during this time of year, making individuals more vulnerable to respiratory infections. Here are the main reasons why these illnesses spread more during the fall.
Drop in temperatures
With the arrival of autumn chill, the air becomes drier, especially indoors where heating is often used.
This dry air dries out the mucous membranes of the respiratory tract, notably those of the nose and throat, which play a protective barrier role against infections. When these mucous membranes are dried out, they become less effective at trapping viruses and bacteria, making it easier for them to enter the body.
Increased social proximity indoors
As temperatures drop, people spend more time indoors, whether at work, school, or home.
This proximity in closed spaces promotes the transmission of respiratory viruses, such as those that cause colds and flu. These viruses spread easily in environments where ventilation is limited and individuals are closer to one another.
Weakening of the immune system
The change of season and the reduction in daylight hours also affect our immune system.
In the fall, the days shorten, which can lead to a decrease in the production of vitamin D, an important nutrient for a healthy immune system. Reduced sun exposure, combined with increased stress due to the resumption of activities after the summer, can make the body more vulnerable to infections.
Faster virus spread in cold air
Studies show that certain respiratory viruses, such as the rhinovirus (responsible for the common cold), survive and spread more easily in cold, dry conditions.
The cold can also reduce the ability of the respiratory system to eliminate inhaled viral or bacterial particles.
Back to school and group activities
Fall is also marked by the start of the school year and the return to group activities, which increases interactions between children and adults.
Illustration image Unsplash
Schools, offices, and public transportation become ideal places for the transmission of respiratory illnesses, especially among the youngest, who are more susceptible to infections.