Published on
Updated
Reading 2 mins.
in collaboration with
Dr Gérald Kierzek (Medical Director of Doctissimo)
It’s a question we’ve all asked ourselves at least once: why are we sick more often when it’s cold? It would seem that a team of American researchers has understood the mechanism triggering the decline of our immune defenses, thus allowing an infection to take hold. Explanations.
What is the link between the cold and winter viral infections? So intuitively many of us think there is a connection, scientifically it has never been proven.
An action on the immune system of the nose
Colds, sore throats, ear infections, bronchitis… Respiratory diseases are much more frequent in winter. Does the cold have something to do with it? A team of American researchers has just confirmed that we can “catch a cold”.
According to the conclusions of their study, the cold would be able to neutralize the first line of defense of our body against a virus. A first line composed of spheres with anti-infective power, the release of which is blocked by the cold.
Death of almost 50% of the defense cells
To understand this mechanism, the authors analyzed the way the cells in the front of the nose behave in the presence of a virus. At this point, the cells lining the nose immediately begin to make billions of copies of themselves called extracellular vesicles. The researchers estimate this increase in production at a level of 160%.
But what happens in cold weather? To find out, scientists exposed four study participants to a temperature of 4.4 degrees Celsius for 15 minutes (40 degrees Fahrenheit), then took measurements inside their nasal cavities.
Cold lowers immunity
“What we’ve discovered is that when you’re exposed to cold air, the temperature in your nose can drop by as much as 9 degrees Fahrenheit. And that’s enough to annihilate the three immune benefits of the nose“write the researchers. “In fact, that little bit of cold in the tip of the nose was enough to eliminate almost 42% of the extracellular vesicles”.
Cold air is therefore associated with a great loss of immune defences. Hence the importance of keeping this part of our body warm!
The opinion of Dr Gérald Kierzek, emergency doctor and medical director of Doctissimo
“This study shows that the immune system and our defenses, more generally, begin long before the blood. This confirms what was already known and more fully describes the mechanism involved. It also supports what another study had already shown, namely that regularly cleaning the nose with saline was beneficial for the mucous membranes. and immune defenses. And it also reinforces the common sense advice that our grandmothers could give, such as covering your mouth and nose with a scarf, in very cold weather.“.