6 Reasons Why You Get Sick So Often and How to Better Support Your Immune System

The average adult gets two to three colds a year, according to the Centers for Disease Control and Prevention (CDC). But some of us are prone to getting more. "It does vary, especially among women," says Nikhil Bhayani, MD, an infectious disease expert and epidemiology physician advisor with Texas Health Resources in Bedford, Texas. Women ages 20 to 30, in particular, have more episodes of the common cold than men, he adds (research points to hormone differences and more contact with sick kids as possible reasons for this discrepancy).

Other factors play a role too, and many of them are related to lifestyle stuff you can control. So let's take a look. Here are some of the top reasons why you're getting knocked out so much and how you can bolster your body's defenses.

1. You don't get enough sleep

Been burning the midnight oil lately? That might be your culprit.

According to Dr. Bhayani, less snooze time impairs your body's ability to fight off invading germs—a lot. People who log only six hours of sleep per night are four times more likely to catch a cold when exposed to a virus compared to those who snooze for seven hours or more (the recommended amount for adults), according to a landmark clinical trial in Sleep.

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The CDC recommends adults get at least seven hours of sleep each night, while kids and teens should get even more.

2. You're stressed

As if going through a rough patch wasn't, well, rough enough, it can also make you more likely to get sick. About two times more likely, according to a 2021 Perspectives in Psychological Science study, which looked at factors that make people more susceptible to COVID.

Like sleep deprivation, high levels of chronic stress can suppress your immune system. As a result, any germs you're exposed to have an easier time sneaking past your body's defense system and causing an infection, per the Cleveland Clinic.

3. You've got an underlying health condition

Having a chronic health problem, particularly one that weakens or suppresses your immune system, can up your risk for getting sick more often. Per the Cleveland Clinic, culprits can include:

• Rheumatoid arthritis
• Psoriasis or psoriatic arthritis
• Crohn's disease
• Ulcerative colitis
• Underactive or overactive thyroid
• Multiple sclerosis
• Type 1 diabetes

Basically, if your immune system is tied up with other to-dos related to your chronic condition, it's got less bandwidth to fight off incoming germs. Taking certain meds to manage those conditions, like immunosuppressants or biologics, can add to the effect, per a 2021 Annals of Allergy, Asthma, & Immunology overview.

4. It's your environment

If you've been spending more time in places where there's more germs, there's a good chance you'll end up coming down with more bugs. Maybe you recently started a new job where you're exposed to more people, like a retail, service, or teaching job, per the World Economic Forum. Or maybe you're coming into contact with more surfaces that tend to harbor more germs: Think public doorknobs, shopping carts, shared electronic devices, stair rails, or elevator buttons, notes the CDC.

5. You have kids

Kids are adorable, but they're also basically human petri dishes. So if you've got them at home, you're being exposed to a lot more germs, and are likely to get sick more often, Dr. Bhayani says.

Parents with just one child in the house are 28 percent more likely to come down with a viral infection over the course of the year compared to adults who don't live with children, found an older Clinical Infectious Diseases study. Having two or more kids causes the risk to spike even more.

6. You're short on certain nutrients

Most of us let our healthy eating habits slide at least some of the time (life happens!). But the effects can take their toll over time. Vitamins C, D, and E along with minerals like zinc and selenium play a key role in supporting your immune function. Fall short for an extended period and that could make you more susceptible to getting sick, concluded a 2024 review in Nutrients.

How to prevent getting sick so often

If you suspect that any of the above are responsible for your never-ending sniffle parade, good news: There's plenty you can do to fortify your defenses and reduce your germ exposure.

• Become a habitual hand-washer. Just sudsing up regularly can slash your risk for respiratory infections by 20 percent and your risk for stomach bugs by 30 percent (!), the CDC says. Get into the swing of doing it at regular times throughout the day, like before you eat and anytime you come home from being out.
• Eat a wholesome diet. Next to washing your hands, it's one of Dr. Bhayani's top tips for supporting a strong immune system. While there are lots of ways to eat healthy, a Mediterranean-style diet rich in whole grains, fruits and vegetables, beans, nuts and seeds, and healthy fats might have an edge. A 2024 PLOS One study found that it was tied to lower rates of COVID infections, for instance.
• Move every day. Exercise increases your circulation of infection-fighting white blood cells and helps flush respiratory germs out of your lungs and airways. Plus, it's a primo stress-reliever, notes the National Library of Medicine.
• Get enough sleep. Aim for at least seven hours per night. If you're struggling with falling asleep, try this sleep doctor's advice.
• Find time to chill. Stress reduction's another biggie for helping your immune system function at its best, Dr. Bhayani says. So carve out some regular time for activities that help you unwind, like yoga, journaling, listening to some quiet music, or picking up a creative hobby like drawing or painting. Whatever you need to shut your mind off for a while!
• Get vaccinated. The flu shot can lower your risk for getting sick by as much as 60 percent, for instance, notes the Mayo Clinic. And even if you do come down with symptoms, you'll likely bounce back faster.

When to see a doctor

There's no official threshold for how often is too often to get sick. It's really more about knowing what's typical for you and looping your doctor in if you've noticed a change, recommends the Cleveland Clinic. If you normally get a couple colds a year but are suddenly getting a lot more, for instance, that's a sign that something could be up.

FAQ

How many times is it normal to get sick a year?

Two to three colds is the average for a generally healthy adult, the CDC notes. But it's also not unusual to get sick more often, especially if you're regularly in situations where you're exposed to a lot of germs (like having young kids, for instance).

Why do I get a cold every four months?

Your body's internal clock is very...efficient? Just kidding. But if three colds per year is average, that does work out to a bug ever four months or so. Seasonal shifts—particularly winter's cold, dry air—can also make you more vulnerable to illnesses, the Cleveland Clinic notes.

Does getting sick strengthen your immune system?

Sort of. "Our immune systems have memory, meaning that if an individual has previously been exposed to an infectious bug, such as a virus, specialized immune cells remember what it looks like and will continue to circulate in the blood and body fluids," Dr. Bhayani says. In other words, once you fight off a particular cold virus, you'll probably have an easier time fighting it off if you encounter it again.