Based on recent studies
, it appears that our internal body temperature just might be the culprit. As our internal body temperature drops after exposure to cold air, so does our body’s immune system response – reducing our ability to fight off the rhinovirus (virus that causes the common cold).
Akiko Iwasaki, co-author of the study and professor of immunobiology at Yale University School of Medicine says, “It has been long known that the rhinovirus replicates better at the cooler temperature, around 33 Celsius (91 Fahrenheit), compared to the core body temperature of 37 Celsius (99 Fahrenheit).
“[But] the reason for this cold temperature preference for virus replication was unknown. Much of the focus on this question has been on the virus itself. However, virus replication machinery itself works well at both temperatures, leaving the question unanswered,” she says.
“We used mouse airway cells as a model to study this question [and found that] at the cooler temperature found in the nose, the host immune system was unable to induce defense signals to block virus replication,” says Iwasaki.
After incubating the mouse cells in two different temperature settings (one group of cells was incubated at 37 C (99 F) to mimic the core temperature found in the lungs, and the other at 33 C (91 F) to mimic the temperature of the nose), results showed that internal body temperatures did not have any impact on the virus itself. It was in fact, the body’s own “indirect immune response to the virus that differed, with a stronger response observed among the warmer lung cells and a weaker response observed among the colder nasal cells.”