What is the link between the cold and winter viral infections? While 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, tonsillitis, ear infections, bronchitis… Respiratory illnesses are much more common in winter. Does the cold have something to do with it? A team of American researchers has confirmed that we can “catch a cold”.
According to the conclusions of their study, the cold is capable of neutralizing our body’s first line of defense against a virus. A first line composed of spheres with anti-infectious power, the release of which is blocked by the cold.
Death of nearly 50% of defense cells
To understand this mechanism, the authors analyzed how 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 creating billions of copies of themselves called extracellular vesicles. 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 found is that when you’re exposed to cold air, the temperature in your nose can drop as much as 9 degrees Fahrenheit. And that’s enough to negate the nose’s three immune benefits” write the researchers.
“In fact, this little bit of cold in the tip of the nose was enough to eliminate almost 42% of extracellular vesicles”.
Cold air is therefore associated with a great loss of immune defenses. Hence the importance of keeping this part of our body warm!
The opinion of Dr Gérald Kierzek, emergency doctor and medical director of True Medical
“This study shows that the immune system and our defenses, more generally, begin well before the blood. This confirms what we already knew and describes more completely the mechanism at play. It also supports what another study had already shown, namely that regularly cleaning the nose with physiological serum was beneficial for the mucous membranes and the immune system. And this 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.“.