Understanding Winter Illnesses: It’s Not Just the Cold

There’s a new twist on the idea of feeling “under the weather.”

This winter has brought a noticeable rise in flu cases, coupled with low temperatures that might make us think the weather is to blame. But recent studies indicate that the relationship between winter and colds is more complex, and that simply being cold isn’t what leads to infections.

Nevertheless, chilly air does have significant effects on health. Cold weather influences a variety of factors—biological, environmental, and social—that make individuals more vulnerable to respiratory issues.

One reason for the uptick in sniffles could be that certain viruses thrive better in cold, dry air, which allows them to linger longer and remain contagious. These include influenza strains and rhinoviruses, which spread through respiratory droplets from person to person.

Dry air can also cause small droplets from coughs and sneezes to evaporate quickly, producing smaller particles that, well, hang around longer in the air. As a result, others are more likely to breathe them in. This isn’t a fun situation, particularly since dry air reduces moisture in both skin and the mucous membranes in our noses and throats, leading to thinner mucus—a critical component for capturing and flushing out viruses.

When it comes to defending against viruses, winter brings alterations to our bodily mechanisms. Inhaling cold air leads to vasoconstriction, which reduces blood flow—this can weaken our immune responses, making it harder for our bodies to identify and fight off viruses before they lead to sickness.

With lower temps, we often seek shelter indoors, where we’re frequently in close proximity to one another. This kind of environment can facilitate the spread of droplets containing viruses.

A lack of vitamin D, crucial for maintaining a robust immune system, becomes more common during this time too. Research also points out that individuals with respiratory issues, like asthma, can experience heightened symptoms during colder months. Although lower temperatures correlate with an increase in respiratory ailments, activities like stepping outside without a coat or sleeping in cold rooms aren’t direct causes of illness.