Although our parents and grandparents worried that we were warm enough in winter, the truth is that this will not prevent you from falling ill. It is not cold weather that causes people to get the flu, nor does it get a cold. Both respiratory illnesses are caused by viruses: they are spread through germ-filled droplets emitted by sick people when they cough, sneeze, and talk. You can also get sick from touching a contaminated surface, such as someone's hand or a doorknob.)
But that doesn't mean there is no connection between winter, cold weather, and falling ill. There is no question that cold weather is associated with an increase in cold and flu cases.
Colder temperatures can not only create conditions conducive to viruses , but cold weather can also make us more susceptible to contracting them. Here are some of the factors that may explain why "cold and flu season" lines up so well with fall and winter.
4 factors that increase the chances of falling ill in winter
Viruses flourish in colder climates
It is common for people to talk about the "flu season", which normally occurs from October to May , with a peak in flu cases during February.
And it's not just the influenza virus that has a seasonal appearance. Although rhinovirus (the virus that causes the common cold) is present year-round, it peaks in the fall and again in March, according to a January 2019 study in Scientific Reports.
Respiratory syncytial virus , another common respiratory tract virus, is also seen more in colder temperatures, peaking in December, according to the same study.
In addition to being more prevalent in fall and winter, viruses are more likely to thrive in colder climates. They reproduce better, live longer and can stay circulating longer in the air.
The cold makes us spend more time indoors
Office workers are very familiar with the cold of their workplace that travels from one cubicle to another. In close quarters it can seem like there is no escape from germs that are spread from one co-worker who sneezes to another.
And in the winter, of course, most of our activities and gatherings take place indoors, as the colder temperatures make gathering in parks and backyards less than pleasant.
Being around other people we know transmits viruses that are spread by droplets or aerosols. But we don't know that closing windows and people spending more time inside is the trigger for this to spread further; it probably is, it just hasn't been tested.
Cold, dry air affects your nose
Cold temperatures outside, accompanied by intense heat inside, produce dry air and low humidity. There is a lot of evidence that cold, dry air makes you more susceptible to viruses.
For example, there is a relationship between rhinovirus infections and a drop in temperature and humidity in the days before infection, according to a study published in the journal Viruses in September 2016. A drop of moisture, along with the air cold, it can dry out the nasal passages, which is our body's first line of defense.
Breathing cold air can cause the blood vessels in the nose to narrow. This can cause fewer white blood cells to be distributed to the nasal mucosa ; And those are the cells that fight germs.
Also, viruses can flourish in drier air. At lower humidity levels, the flu virus is more infectious, according to a February 2013 study in PLOS One. Keeping humidity levels at 40 percent (or higher) reduces the infectivity of a flu virus in aerosol, according to the study.
Try to have the humidity in your home between 30 and 50 percent. Levels that are too low can increase your susceptibility to viruses, but a home that's too humid can lead to bacteria and mold growth, which is also a problem for your health.
We get less vitamin D
Winter has the shortest days, so people's vitamin D levels drop as well. There may be a connection between vitamin D and the immune system. Having a marked deficiency of this vitamin seems to affect your immune function.
Taking supplements can be helpful in preventing respiratory diseases, particularly for people with vitamin D deficiency, according to a February 2017 meta-analysis of 25 studies in The BMJ.
How to avoid colds in winter?
Avoiding colder weather, and the circumstances we create for viruses, is probably not an option. But of course, there are many things you can do to prevent exposure to viruses, lowering your chance of catching a cold or the flu.
The strategies are simple and probably familiar. T and starts vaccinating against influenza. Also, eat healthy, stay hydrated, exercise regularly, and get enough sleep.
Of course, you should stick with hand washing and social distancing . The same methods used to limit the spread of COVID-19 can also work to mitigate the spread of other colds and flu.
