Cold weather does not make people sick, but it can weaken the body’s defenses and create conditions that allow viruses to spread more easily.
Cookeville Regional Urgent Care Physician Assistant Lucas Pittman said many patients still believe sudden temperature changes cause colds or the flu. Pittman said Illnesses comes from exposure to viruses rather than the weather itself.
“That’s not really true,” Pittman said. “Cold weather can lower your immune system and make you more easily get sick, but specifically the transition from warm to cold isn’t necessarily making you sick.”
Pittman said colder months create an environment that helps viruses survive longer while also affecting how the body protects itself. He said dry, cold air impacts the nose and airways, which normally help filter out germs.
“Cold weather helps stabilize viruses and keeps them from dying off as quickly,” Pittman said. “The dryness of the air dries out the nasal airways and that mucus that helps push viruses and bacteria out, and it makes those defenses not work as effectively.”
He said human behavior during colder months also plays a major role in illness spread. Pittman said people spend more time indoors, often in crowded or poorly ventilated spaces.
“When it’s cold outside, people are much more likely to be inside,” Pittman said. “Crowded indoor spaces make it much easier to pass viruses to other people, and heating systems can recirculate contaminated air.”
Pittman said reduced sunlight during winter can also affect immune strength. He said less sunlight can lower vitamin D levels, which plays a role in immune response.
“Less sunlight during the day decreases the amount of vitamin D in the body,” Pittman said. “That’s another way your immune system can be lowered during colder months.”
Cold, dry air can also strain the lungs, even without causing illness, Pittman said. He said breathing cold air can feel harder, especially for people with asthma or other breathing conditions.
“The cold, dry air is pretty hard on the lungs,” Pittman said. “It tires you out a lot quicker and makes working outside in cold weather harder, even if you’re bundled up.”
Pittman said simple steps can help reduce illness risk during winter. He said frequent handwashing, good sleep, proper nutrition, and managing indoor humidity all support immune health.
“Washing your hands often is one of the best ways to do it,” Pittman said. “Getting good sleep strongly affects your immune system, and some extra humidity during winter can help viruses not live as long.”
He said one of the biggest misconceptions he hears is that stepping outside into the cold causes sickness. Pittman said understanding how viruses spread is key to staying healthy during winter months.
“The cold is actually caused by a respiratory virus,” Pittman said. “It’s not from going outside into the cold air.”