Zip up your coat or you’ll catch a cold.
Most people have probably heard some variation of that parental plea while growing up, or even directed such advice to their own children. It’s a sensible request, though when it comes to avoiding illness when temperatures dip, it’s not quite so simple.
“It’s multifactorial. Just given cold weather alone doesn’t make you sick,” said Dr. Virginia Banks of Northeast Ohio Infectious Disease Associates in Youngstown. “There are just a lot of variables.”
Some viruses thrive in winter
For one, viruses may survive and reproduce more easily in the cold, dry air of winter. Plus, cold weather keeps people indoors, and viruses can spread more easily in close quarters. And although laboratory research suggests cold temperatures can make immune cells less effective, Banks said in the end, viruses — not the cold weather — are what make you sick.
While many respiratory viruses cause the common cold, rhinoviruses are the most common trigger for those runny noses, according to the Centers for Disease Control and Prevention. Rhinoviruses also can cause asthma attacks and have been linked to sinus and ear infections.

American Heart Association/Tribune News Service
Most versions of rhinoviruses replicate more robustly in nasal passages, where the temperature is usually about 91 to 95 degrees, lower than the core body temperature of 98.6. “Viruses tend to enter the body through your nasal passages, and the temperature being lower lends itself to them replicating,” Banks said.
Influenza viruses and the virus that causes COVID-19 also can enter the body through the nose.
How to avoid getting sick
Banks is eager to see how active this winter’s flu season will be after the CDC said activity for the 2020-21 season was “unusually low.” Likely explanations included the introduction of pandemic mitigation measures.
To avoid getting sick this winter, Banks said those measures — wearing masks, especially indoors; social distancing; staying home; and hand-washing — provide an important layer of protection. And she urged people to get their flu and COVID vaccines. Other tips to keep the immune system strong include exercising, eating a healthy diet and getting enough sleep.
She also implored people to schedule checkups with their doctor if they have avoided visits during the pandemic. That’s because viruses aren’t the only health issue people should be thinking about this winter.
Some research shows an association between colder air temperatures and adverse impacts on cardiovascular health. For instance, a 2018 study in Sweden published in JAMA Cardiology found more heart attacks happened on days with low air temperatures, low air pressure, higher winds and shorter duration of sunlight.
Why low temps are associated with sickness
A 2016 study in the Journal of Stroke and Cerebrovascular Diseases found lower average air temperatures and bigger 24-hour temperature swings were associated with hospitalizations for stroke. The authors cited a need for more research to determine why.
Theresa Beckie, a professor in the College of Nursing and College of Medicine Cardiology at the University of South Florida in Tampa, urged those diagnosed with heart disease to be particularly cautious in the cold.
“A really good example is that there have been several studies of sedentary individuals shoveling snow after a heavy snowfall,” Beckie said. “These weekend warriors, if they have ischemic heart disease, have a risk of precipitating a heart attack.”
Sudden exertion stimulates adrenaline and a stress response in your body that may increase heart rate, Beckie said. “So yes, there is a risk, but it’s not so much due to the cold but the sudden physical activity of holding your breath, shoveling snow and creating sudden stress on the heart.”
It’s still important to stay active in the winter, though Beckie said people should be mindful of their physical fitness before jumping straight into too strenuous of an activity. For instance, someone who is not as active should take breaks while clearing a foot of snow from their driveway, or to pay a service to do it.
“Acclimation is everything,” Beckie said. “Just take things slowly.”
American Heart Association News covers heart and brain health. Not all views expressed in this story reflect the official position of the American Heart Association. Copyright is owned or held by the American Heart Association Inc., and all rights are reserved. If you have questions or comments about this story, please email editor@heart.org.
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Feeling the winter blues? Here are some reasons why
Milos Batinic // Shutterstock
With winter comes cold weather, a reduction in sunlight, and the potential to feel a bit down. The winter blues are common and can cause tiredness and a shift in mood, though they don't normally hinder your ability to find enjoyment in life. Winter blues normally clear up on their own or can be aided by getting more exposure to daylight, vitamin D supplements, or by adding certain foods such as omega-3 fatty acids and protein to your diet.
Seasonal affective disorder (SAD) is much more than winter blues, it is a form of depression related to the change in seasons and the shortening of daylight hours. It occurs in areas of the world where there is less sunlight during specific seasons. This lack of sunlight can throw circadian rhythms—which influence our sleep-wake cycle—out of whack, and cause deficiencies in certain vitamins and hormones in the brain such as serotonin, which helps to regulate mood.
SAD is much more prevalent in northern latitudes of the world than southern areas. It usually occurs during the late fall and winter months. Symptoms include changes in mood, fatigue, depression, feelings of hopelessness, and social withdrawal. The link between seasonal depression and light was first identified by National Institutes of Health researchers in the early 1980s. . Treatment includes behavioral changes such as increasing access to daylight or clinical approaches such as light therapy (phototherapy), talk therapies like cognitive behavioral therapy, and medications such as certain antidepressants.
Citing studies from Mount Sinai’s REVOLV Study, which was sponsored by View Inc.; the Journal of Psychiatry and Neuroscience; the Endocrinology and Metabolism Clinics of North America; and other health organizations, View compiled a list of reasons you might be feeling the winter blues and how you can combat it.

Milos Batinic // Shutterstock
With winter comes cold weather, a reduction in sunlight, and the potential to feel a bit down. The winter blues are common and can cause tiredness and a shift in mood, though they don't normally hinder your ability to find enjoyment in life. Winter blues normally clear up on their own or can be aided by getting more exposure to daylight, vitamin D supplements, or by adding certain foods such as omega-3 fatty acids and protein to your diet.
Seasonal affective disorder (SAD) is much more than winter blues, it is a form of depression related to the change in seasons and the shortening of daylight hours. It occurs in areas of the world where there is less sunlight during specific seasons. This lack of sunlight can throw circadian rhythms—which influence our sleep-wake cycle—out of whack, and cause deficiencies in certain vitamins and hormones in the brain such as serotonin, which helps to regulate mood.
SAD is much more prevalent in northern latitudes of the world than southern areas. It usually occurs during the late fall and winter months. Symptoms include changes in mood, fatigue, depression, feelings of hopelessness, and social withdrawal. The link between seasonal depression and light was first identified by National Institutes of Health researchers in the early 1980s. . Treatment includes behavioral changes such as increasing access to daylight or clinical approaches such as light therapy (phototherapy), talk therapies like cognitive behavioral therapy, and medications such as certain antidepressants.
Citing studies from Mount Sinai’s REVOLV Study, which was sponsored by View Inc.; the Journal of Psychiatry and Neuroscience; the Endocrinology and Metabolism Clinics of North America; and other health organizations, View compiled a list of reasons you might be feeling the winter blues and how you can combat it.

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Feeling the winter blues? Here are some reasons why
Kichigin // Shutterstock
The body’s circadian rhythm, or internal clock, controls the sleep-wake cycle. With the changing of seasons and the decrease in sunlight that accompanies winter, circadian rhythms can be thrown out of whack. This can impact sleep, and that can affect your overall mood and mental health. According to Harvard Health, not only do circadian tendencies determine your sleep cycle—whether you are a night owl or a morning person—but they can also impact a person’s “choice of emotional coping skills, such as assertiveness or rationalization, and their predisposition to psychological disorders.” When irregular circadian rhythms interfere with one’s sleep and overall ability to function, it can also lead to mood disorders and seasonal affective disorder.
Kichigin // Shutterstock
The body’s circadian rhythm, or internal clock, controls the sleep-wake cycle. With the changing of seasons and the decrease in sunlight that accompanies winter, circadian rhythms can be thrown out of whack. This can impact sleep, and that can affect your overall mood and mental health. According to Harvard Health, not only do circadian tendencies determine your sleep cycle—whether you are a night owl or a morning person—but they can also impact a person’s “choice of emotional coping skills, such as assertiveness or rationalization, and their predisposition to psychological disorders.” When irregular circadian rhythms interfere with one’s sleep and overall ability to function, it can also lead to mood disorders and seasonal affective disorder.
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Feeling the winter blues? Here are some reasons why
baranq // Shutterstock
The decrease in sunlight during the winter months can cause a reduction in serotonin levels. Serotonin is a chemical in the brain and a key hormone that influences mood and helps with mood stabilization. It also plays a role in sleep and digestion. When serotonin levels drop or are unbalanced, it can impact our mood and bring on the blues, trigger depression, and even cause SAD. Both exercise and exposure to bright light can help balance and increase serotonin levels in the winter months.
baranq // Shutterstock
The decrease in sunlight during the winter months can cause a reduction in serotonin levels. Serotonin is a chemical in the brain and a key hormone that influences mood and helps with mood stabilization. It also plays a role in sleep and digestion. When serotonin levels drop or are unbalanced, it can impact our mood and bring on the blues, trigger depression, and even cause SAD. Both exercise and exposure to bright light can help balance and increase serotonin levels in the winter months.
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Feeling the winter blues? Here are some reasons why
travelview // Shutterstock
Sunlight stimulates the production of vitamin D, which can mean a deficiency of the essential micronutrient during winter’s shorter days and diminished sunlight.
Vitamin D plays a major role in warding off depression and regulating mood and is thought to promote serotonin activity. A vitamin D deficiency can impair brain health and cognitive functioning and can affect mood and behavior. Adding a vitamin D supplement can help with depression and mood regulation, but it can take up to three or four months to see the benefit. Age can also impact how much vitamin D your body produces.
travelview // Shutterstock
Sunlight stimulates the production of vitamin D, which can mean a deficiency of the essential micronutrient during winter’s shorter days and diminished sunlight.
Vitamin D plays a major role in warding off depression and regulating mood and is thought to promote serotonin activity. A vitamin D deficiency can impair brain health and cognitive functioning and can affect mood and behavior. Adding a vitamin D supplement can help with depression and mood regulation, but it can take up to three or four months to see the benefit. Age can also impact how much vitamin D your body produces.
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Feeling the winter blues? Here are some reasons why
fizkes // Shutterstock
While your body often produces too little of certain vital vitamins and hormones, like serotonin, during the winter months, it can also produce too much of others. In the winter, producing too much melatonin during the day can lead to sluggishness and low energy levels. Melatonin is a hormone made by the pineal gland that is produced in response to darkness, and it can impact sleep. With the shorter days during the winter months, however, the body often produces too much melatonin during the day and not enough melatonin during the evening, causing sadness and depression. Opening your curtains or blinds to let in more daylight, especially early in the morning, can help regulate melatonin levels, resulting in 11% lower anxiety and 9% lower stress levels.
fizkes // Shutterstock
While your body often produces too little of certain vital vitamins and hormones, like serotonin, during the winter months, it can also produce too much of others. In the winter, producing too much melatonin during the day can lead to sluggishness and low energy levels. Melatonin is a hormone made by the pineal gland that is produced in response to darkness, and it can impact sleep. With the shorter days during the winter months, however, the body often produces too much melatonin during the day and not enough melatonin during the evening, causing sadness and depression. Opening your curtains or blinds to let in more daylight, especially early in the morning, can help regulate melatonin levels, resulting in 11% lower anxiety and 9% lower stress levels.
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Feeling the winter blues? Here are some reasons why
Southworks // Shutterstock
During the winter months, many people find they get less physical activity and exercise due to the cold, snowy, and icy weather conditions. Exercise can increase endorphins and serotonin levels in the brain, which help to improve one’s overall well-being and mood. Lack of physical activity can decrease the production of these feel-good chemicals in the brain. Exercise is an effective tool in treating both the winter blues and seasonal affective disorder. To improve mood, taking a brisk walk on a sunny winter day or joining a local gym can be a good way to chase away the winter blues.
This story originally appeared on View and was produced and distributed in partnership with Stacker Studio.
Southworks // Shutterstock
During the winter months, many people find they get less physical activity and exercise due to the cold, snowy, and icy weather conditions. Exercise can increase endorphins and serotonin levels in the brain, which help to improve one’s overall well-being and mood. Lack of physical activity can decrease the production of these feel-good chemicals in the brain. Exercise is an effective tool in treating both the winter blues and seasonal affective disorder. To improve mood, taking a brisk walk on a sunny winter day or joining a local gym can be a good way to chase away the winter blues.
This story originally appeared on View and was produced and distributed in partnership with Stacker Studio.