Snapshot: Cold, extremely cold. Sniffling nose, inflamed nostrils and shivers walking through your spine. “Ah! For sure this winter temperature will make me sick!”
Who did not experience the above-mentioned situation in his/her life? Who did not curse winter and its low temperature for making you sick?
Well, let me tell you: Cold is a “joke”. No evidence is supporting the fact that cold weather actually makes you more prone to get a cold. No scientific evidence supports this long-held belief, and now I will demonstrate you why.
Back in 1958, Dowling and colleagues checked whether “cold” transmission was influenced by environmental conditions. They had three groups:
- the first group was in a room with -12 Celsius degrees (10 Fahrenheit) dressed up with overcoats, gloves and hats.
- the second group in a room 15 Celsius degrees (60 Fahrenheit) in underwear
- the third group in a room with 26 Celsius degrees (80 Fahrenheit) in underwear
All the groups were actually infected with the mucus of a sick person in their noses and monitored to see if they became sick. These “brave” volunteers showed us that temperature did not affect their likelihood to get sick. 1
Another article published in 1968 in New England Journal of Medicine showed that several volunteers exposed to cold environments were not more susceptible to get Rhinovirus common cold. This work meticulously addressed this issue using several techniques to follow infected patients and clearly demonstrated that cold temperature does not play a major role in making us sick.2
Paradoxically, Brenner and colleagues showed in an article appeared in Journal of Applied Physiology that acute cold exposure has even immuno-stimulating effects!3
So, why flu viruses are seasonal and we get sicker in winter than in summer? It seems indeed that viruses like much more winter. One possible explanation is that during winter we tend to gather together in closed places. In this kind of situation is much easier to be infected compared with a summer time in which everybody is in open spaces striving for “fresh air” far away from the others!
Another scenario is given by a research of Prof Peter Palese’s group. They have shown that Influenza Virus transmission in guinea pigs – as animal model – was increased in cold and dry conditions. Of note, increased infection rate was not due to cold-weakened immune system. The latter finding suggests that probably cold and dry air helps the virus to linger for longer time in the air increasing the infection probability.4
Not to be underestimated is the psychosomatic component: a study showed that people exposed to cold are more inclined to report symptoms even though the probability of getting a real infection was the same to the control group.5
It is clear that beliefs die hard when are so deeply rooted in the common mentality. But this is why we should always.. Take it Science!