Friday, December 17, 2021 (American Heart Association News)-zip up your jacket, or you will catch a cold!

Most people may have heard some changes that their parents begged for when they were growing up, and even applied such suggestions directly to their children. This is a wise request, although it is not so simple to avoid getting sick when the temperature drops.

"This is multifactorial. Just because of cold weather will not make you sick," said Dr. Virginia Banks of the Infectious Diseases Association of Northeast Ohio, Youngstown. "It's just that there are many variables."

On the one hand, the virus may be easier to survive and multiply in the cold and dry air in winter. In addition, cold weather keeps people indoors, and the virus is more likely to spread at close range. Although laboratory studies have shown that cold temperatures reduce the effectiveness of immune cells, Banks concluded that it is the virus—not the cold weather—that makes you sick.

According to the Centers for Disease Control and Prevention, although many different respiratory viruses can cause the common cold, rhinovirus is the most common cause of a runny nose. Rhinovirus can also cause asthma attacks and is associated with sinus and ear infections.

Most versions of rhinovirus replicate more strongly in the nasal cavity. The temperature of the nasal cavity is usually about 91 to 95 degrees, which is 98.6 below the core body temperature. Banks said: "Viruses often enter the human body through the nasal cavity, and lower temperatures help them replicate."

Influenza viruses and the virus that causes COVID-19 can also enter the body through the nose.

After the CDC stated that flu activity during the 2020-21 flu season was "exceptionally low", Banks was eager to know how active this winter flu season will be. Possible explanations include pandemic mitigation measures.

To avoid getting sick this winter, Banks said that these measures—wearing masks, especially indoors; social isolation; staying at home; and washing hands—provide an important layer of protection. She urged people to get the flu and COVID vaccines. Other tips for keeping the immune system strong include exercise, healthy eating, and adequate sleep.

She also urged people to arrange for examinations by doctors who avoid seeing them during the pandemic. This is because the virus is not the only health issue that people should consider this winter.

Some studies have shown that there is an association between colder temperatures and adverse effects on cardiovascular health. For example, a Swedish study published in JAMA Cardiology in 2018 found that the incidence of heart attacks is higher on days with lower temperatures, lower air pressure, higher wind, and shorter sunshine hours.

A 2016 study published in the Journal of Stroke and Cerebrovascular Disease found that lower average temperatures and larger 24-hour temperature fluctuations are associated with stroke hospitalization. The author points out that more research is needed to determine the cause.

Theresa Beckie, a professor in the School of Nursing and Cardiology at the University of South Florida in Tampa, urges those diagnosed with heart disease to be especially careful in the cold.

"A good example is that there are several studies of sedentary people shoveling snow after heavy snowfall," Becky said. "These weekend warriors, if they have ischemic heart disease, they are at risk of inducing a heart attack."

Becky said that sudden exertion stimulates adrenaline and the body's stress response, which may increase the heart rate. "So yes, there are risks, but this is not because of the cold, but because of sudden physical activity, such as holding your breath, shoveling snow, and causing sudden stress on the heart."

It’s still important to stay active in the winter, although Becky says that people should pay attention to their health before going directly into overly strenuous activities. For example, a less active person should take a break while clearing a foot of snow from the driveway—or pay for the service.

"Adaptation is everything," Becky said. "take it easy."

American Heart Association News reports on heart and brain health. Not all opinions expressed in this story reflect the official position of the American Heart Association. The American Heart Association owns or holds the copyright, and all rights are reserved. If you have any questions or comments on this story, please send an email to editor@heart.org.