Doctors have long puzzled over the connection between colds, flu, and winter.
Cold and flu symptoms are undeniably more common in cooler weather, but low temperatures don’t actually
cause colds. So what is the relationship between cold and flu symptoms and chilly temperatures?
How cold and flu viruses spread
Humidity may help you
reduce cold and flu infections. Often you fall victim to a virus when an infected person
sneezes or
coughs. Droplets from sneezes can travel 15 feet and propel some 40,000 potentially infectious droplets. That’s why homes, offices, and classrooms are easily contaminated.
1 High humidity, though, cuts down this distance, so viruses are suspended for less time in warm, heavy air than they are in cold, dry air – and are less likely to be inhaled.
The other common
way to catch cold and flu is through contact with contaminated surfaces, whether that’s an infected person or an object that has been touched or coughed on. Solid surfaces transmit the virus more readily than porous surfaces, such as towels and upholstery.
How viruses attach to you
Once a cold or flu virus gets into your mouth, eyes, or nose, it goes to work quickly. Rhinovirus, the most common type of cold virus, attaches itself in the respiratory tract within 15 minutes of contact, and starts to infect the lining of the nose and throat. Symptoms often appear eight to 10 hours later,
2 leading to sneezing, a
runny nose and an
irritated throat. These symptoms worsen slightly over a period of a week to 10 days, whereas flu’s incubation period can be longer (two to five days) but when it hits, it hits hard and fast. Fever and pronounced muscle weakness are telltale signs of flu but nearly unheard of for a cold.
Maintain virus awareness
There truly is no cure for the
common cold. Hand washing and avoiding infected people are your best defence, but not everyone who carries a cold virus shows symptoms. Even those who appear healthy can be contagious – including you!
1 Characterization of Infectious Aerosols in Health Care Facilities. National Institutes of Health. American Journal of Infection Control. Aug. 1998. http://www.ncbi.nlm.nih.gov/pubmed/9721404
2 Rhinovirus: An Unstoppable Cause of the Common Cold. The Science Creative Quarterly. Aug. 2004. http://www.scq.ubc.ca/rhinovirus-an-unstoppable-cause-of-the-common-cold/