What Causes the Common Cold?
You know the drill. Your throat's a little scratchy, and you start sneezing and coughing and feeling kind of eh. Pretty soon you're in the grip of a nasty cold. To add insult to injury, all that big-time misery is from a tiny invader called a virus.
And it's not just one you need to dodge. There are more than 200 viruses linked to the common cold. Here's how a cold happens, common cold causes, and what you can do to feel better.
What Viruses Cause the Common Cold?
A cold is another name for an upper respiratory infection. You catch one when germs infect your upper respiratory tract, which includes your:
- Nose. Your nostrils serve as the entrance to your respiratory system.
- Nasal cavities. These are the hollow spaces that let air flow into and out of your nose.
- Sinuses. Air-filled spaces in your cheeks and forehead, your sinuses warm and filter the air you breathe into your body. They also affect how your voice sounds, among other things.
- Larynx. You might also hear this called your voice box.
Your entire respiratory system is lined with membranes that produce a slippery liquid called mucus. It helps trap some foreign invaders, like dust and pollen, that try to sneak by. Tissues inside your nasal cavities also help clean the air you inhale. But as fine-tuned as this system is, it's not perfect. And germs can still sometimes find a way in.
Here are a few of the most common cold viruses.
Rhinovirus. Doctors have found three different types and at least 169 different strains of rhinovirus around the globe. It's most active in early fall, spring, and summer. Rhinoviruses cause 10%-40% of colds. You'll feel miserable when you catch one, but they rarely make you seriously sick.
Coronavirus. This group of viruses is common in people and animals. They were discovered in the 1960s. Some kinds only cause mild cold symptoms, but a newer kind, SARS-CoV-2, causes COVID-19. A coronavirus strain is most likely to cause your cold in the winter and early spring.
Respiratory syncytial virus (RSV). This virus is so common that most kids have it by the time they turn 2 years old. While RSV symptoms are often mild, they can get severe enough that you'll need to go to the hospital.
Human parainfluenza virus (HPIV). Researchers have found four types of this family of viruses. HPIV-1 and HPIV-2 are the kinds most likely to give you a cold.Sometimes HPIV can cause more severe conditions like croup, bronchitis, and pneumonia.
There are also a lot of cold viruses that doctors haven't identified. About 20%-30% of colds in adults are caused by an "unknown" bug.
How cold germs enter your body
Colds are highly contagious. Common ways you can catch one include:
- Being around someone with a cold who coughs, sneezes, or talks close to you
- Sharing objects like towels or sheets that have the virus on them
- Touching your eyes, nose, or mouth after touching something that has a cold virus on it
Common Cold Myths
There's a lot of false or misleading health information online, especially on social media sites or websites that are trying to sell you products. Here's what you might have heard about common colds and whether it's true.
Myth: Being out in cold weather will give you a cold.
Fact: Generally, you do come into contact with more germs outdoors than indoors. But there's no proof that you'll get sick from spending time in cold temps.
Myth: Being overheated can make you sick.
Fact: Hot weather can lead to many health issues, from dehydration (not getting enough fluids) to heat stroke. It can also worsen chronic health conditions like asthma, diabetes, and heart disease. Results of an early study appear to show that short-term exposure to hot temperatures could increase inflammation in your body and keep your immune system from working at its best. But more research is needed to better understand this link.
Myth: Dairy products can lead to a cold.
Fact: You may have heard that eating or drinking dairy products causes your body to make more mucus, and that excess buildup can lead to a cold. That isn't true. But some dairy products can coat your mouth and throat, making them feel slimy. That may remind you of how congested, or stuffed up, you feel when you're sick with a cold.
Myth: Vitamin C can help you stave off a cold.
Fact: Studies show that vitamin C has a lot of health benefits, including helping your immune system work well. Even so, this potent vitamin can't prevent you from catching a cold.
What vitamin C can do is speed up your recovery process if you do get sick. Eating plenty of fruits and vegetables should provide you with the C you need. If you want to take a supplement, look for one that doesn't exceed 500 milligrams. Check with your doctor before you start, especially if you have other health issues or already take other medications or supplements.
Myth: You're getting sick because your tonsils or adenoids are large.
Fact: If your tonsils and adenoids get infected, they can cause cold-like symptoms.
Your tonsils are small pads at the back of your throat. They help make white blood cells that fight off germs. Most people's tonsils are about the same size, but repeated infections can make your tonsils bigger. That can lead to other health issues, including trouble breathing and sleep apnea.
Like tonsils, adenoids are also part of your immune system. These tissues hang above your tonsils and also help catch germs. Most of the time, adenoids get smaller in childhood, but infections, like a cold, can cause them to swell up. That can cause symptoms like a runny nose and sore throat. Enlarged adenoids that don't come back down in size are rare in adults. If they're causing issues, your doctor may treat them with antibiotics or remove them.
Myth: Allergies don't make a cold more likely.
Fact: Research suggests that allergies that affect your nose or throat may raise your chances of getting infected by a cold virus. On the other hand, some viruses may also make you more likely to have allergies or asthma.
Myth: Stress isn't good for your immune system.
In small doses, stress can activate your immune system. In the short term, that can be a good thing. Your body's defenses are ready to fight. But if your feelings of stress don't go away, your immune system never "turns off." Over time, that can hurt your health. Your body actually starts to make fewer white blood cells to fight off infection. That makes catching a common cold more likely.
Other Causes of the Common Cold
Despite all that researchers have learned about the common cold, there's a lot more to uncover. For instance, the causes of 20%-30% of adult colds remain unknown.
What is certain is that many factors can increase your chances of catching a cold. The list includes:
Being in a crowded indoor area. Cold germs can spread quickly and easily in places like schools, childcare centers, and airports.
Low humidity. Very dry air can dry out your nasal passages. Without as much mucus, germs have an easier time infecting you.
Smoking. Even being around secondhand smoke makes it more likely that you'll get sick.
Not getting enough sleep. One study found that people who slept less than seven hours each night were three times more likely to catch a cold than people who slept eight hours or more.
Takeaways
More than 200 different types of viruses can cause the common cold, or what's known as an upper respiratory infection. Most adults catch two to three colds every year, but kids often get sick more. Usually, colds go away on their own within a week. But call your doctor if you or your child has a fever, has trouble breathing, becomes dehydrated, or your symptoms are severe.
Common Cold Causes FAQs
What are the five stages of a cold?
They include:
Common cold incubation period. Right after you've been infected, the virus begins making copies of itself inside your body. You won't have symptoms yet. This stage can last anywhere from 12 hours to three days.
Symptomatic period. Here's where you start feeling bad. Cold symptoms are usually at their worst between the first and third day.
Remission period. Your symptoms start to improve. This typically happens three to 10 days after you were infected with the virus.
Recovery period. You may still have a few symptoms, but they'll be mild and probably won't interfere with your daily routine.
How long should a cold last?
Most of the time, colds are short-lived. You should start to feel better 7 to 10 days after you were infected. Your cough may linger a while longer.
If your symptoms get worse, not better, or come back after they went away, call your doctor.
What's the cure for the cold?
There's no way to cure a cold. But there are a few things you can do to relieve your symptoms and feel more comfortable, such as:
- Get more rest. This lets your body have time to heal.
- Drink plenty of fluids. Not only will this keep you from getting dehydrated, but can help loosen your stuffy nose. Besides water, try unsweetened teas or warm chicken soup or broth.
- Use a humidifier to add more moisture into your air. Even the steam from a hot shower could help you breathe more easily.
- Gargle with warm salt water to soothe a scratchy throat. Use 1/4 or 1/2 teaspoon of salt in 8 ounces of water. (Don't try this in kids younger than 6 years old. They may end up swallowing it instead.)
- Soothe your throat with ice chips.
- Use over-the-counter products. For instance, an over-the-counter pain reliever can help with aches and pains. An antihistamine could help dry up your congestion. Ask your doctor or pharmacist which product is best for you, especially if you take prescription medication or have an ongoing health issue. Children and teenagers should never take aspirin. It's been linked to a condition called Reye's syndrome, which can sometimes be life-threatening.
How long can a cold virus live outside your body?
It depends on a lot of factors, including how humid it is and how much the air is circulating. But generally speaking, common cold germs can survive:
- On a metal surface like a doorknob for two to four hours
- On a plastic surface like a TV remote or keyboard for four to eight hours
- On clothing, towels, and bedding for one to three days
- On glasses and ceramic plates for one to seven days
- On wooden surfaces for up to 14 days
