How to Keep Your Immune System Healthy: 8 Tips
Vaccines and Your Immune System

8 Ways to Keep Your Immune System Healthy

8 Ways to Keep Your Immune System Healthy
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Updated on December 17, 2025
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Your immune system is a combination of skin cells, blood, bone marrow, tissues, and organs that defend your body against illness and disease. When working properly, this system protects against potentially harmful pathogens like bacteria and viruses, and limits damage from noninfectious agents, like sunburn or cancer.

For this delicate system to work properly, every piece needs to be functioning at its best. The best way to ensure that? Practicing healthy habits that can boost your immune system every day. Here are eight expert-approved habits to stay healthy.

1. Incorporate Physical Activity Each Day

Studies have shown that regular exercise lowers your risk of chronic diseases, like obesity and type 2 diabetes, as well as viral and bacterial infections.

 Physical activity also increases the release of endorphins (a group of hormones that reduce pain and create feelings of pleasure), making it a great way to manage stress.

“Since stress negatively impacts our immune system, this is another way exercise can improve immune response,” says Yufang Lin, MD, an integrative medicine doctor at the Cleveland Clinic in Ohio.

While some studies suggest that long, intense exercise sessions may suppress the immune system (making you more susceptible to illness and infection after your workout), others contradict this.

 But studies found that in general, active people tend to have lower incidences of both acute illnesses (infections) and chronic ones (cancer or diabetes).

Even on a cellular level, research has found that exercise is associated with a more vigilant immune system, sending immune cells to parts of your body (like muscles, for example) to aid in repair or fighting inflammation.

In general, most adults should aim to get at least 150 minutes of moderate-intensity aerobic exercise — like walking, jogging, or cycling — or 75 minutes of high-intensity aerobic exercise, like running, per week.

 And don’t feel pressure to meet the 10,000-step-a-day goal: Researchers have found that increasing step count, regardless of intensity, is beneficial for lengthening lifespan.

Strength training at least twice a week is also beneficial, fortifying your bones, improving muscle mass, and strength.

 Studies have found that muscle-building exercise can strengthen the immune system and potentially protect against viral infections.

For even more immune system benefits, take your exercise outside. Lin says that time in nature has been shown to support mood, lower blood pressure, reduce inflammation, and support immune system health.

 The sights and sounds of nature have also been shown to activate the parasympathetic nervous system — often referred to as the “rest and digest” side of the nervous system, which plays a key role in immune health.

Plus, exposure to sunshine also boosts vitamin D in the body, another huge factor in immune health.

2. Reach for Nutritious Foods and Stay Hydrated

The nutrients you get from food — in particular, plant-based foods like fruits, vegetables, herbs, and spices — are essential to keeping your immune system functioning properly, says Lin. “Many plant-based foods also have antiviral and antimicrobial properties, which help us fight off infection,” adds Lin.

Spices like clove, oregano, thyme, cinnamon, and cumin, for example, curb the growth of food-spoiling bacteria like Bacillus subtilis, harmful fungi like Aspergillus flavus, and antibiotic-resistant microorganisms like Staphylococcus aureus.

Other nutrients you get from the food — including vitamin A, zinc, probiotics, and vitamins C and D — help your immune system do its job.

For instance, research suggests vitamin C deficiency may increase the likelihood of infection.

 Because the body does not produce this essential water-soluble vitamin on its own, relying on vitamin C–rich foods like citrus, kiwis, and cruciferous vegetables is crucial. In fact, just ½ cup of raw red pepper offers about 95 milligrams (mg) of vitamin C — 106 percent of your recommended daily value.

Protein is also critical for immune health: The amino acids in this macronutrient help create antibodies used to fight infections.

 Try getting more protein from plant sources like legumes, nuts, and seeds whenever possible. Poultry (chicken, turkey, and duck) and seafood are also nutritious protein sources, plus red meat (unprocessed beef, pork, and lamb) on a limited basis. Avoid ultra-processed meats like bacon or hot dogs.

Ultimately, focus on eating plants and plant-based foods for immune health. Add fruits and vegetables to soups, stews, smoothies, and salads, or eat them as snacks, Lin says. Focus on vitamin A– and C-rich produce like:

  • Carrots
  • Broccoli
  • Spinach
  • Red bell peppers
  • Apricots
  • Citrus fruits (oranges, grapefruit, tangerines)
  • Strawberries
And add sources of vitamin E, protein, and zinc, like nuts, seeds, lean meat, and poultry.

Additionally, make sure you are properly hydrated throughout the day. “Dehydration can negatively affect your health and hinder your physical performance, focus, mood, and heart and kidney function,” says Vivek Cherian, MD, an internal medicine physician based in Baltimore. “These complications can increase your susceptibility to illness.”

3. Get Plenty of Restorative Sleep

Your body heals and regenerates while you sleep, making adequate sleep critical for a healthy immune response, Lin says. More specifically, studies have found that sleep is a time when your body regulates key immune cells and molecules like cytokines (a type of protein that can either fight or promote inflammation)

 and T cells (a type of white blood cell that regulates immune response).

“Getting adequate rest may strengthen your body’s natural immunity,” Cherian says. When you don’t get enough sleep, your immune system may not function as well, making it less able to defend your body against harmful invaders and making you more likely to get sick.

Research suggests healthy adults with insomnia are at an increased risk of infection compared with healthy adults without the sleep condition.

 Sleep deprivation also elevates the levels of our stress hormone cortisol, which, of course, is also not good for immune function, Lin says. “Our immune system wears down as a result, and we tend to have [fewer] reserves to fight off or recover from illness.”
It’s recommended that adults get between 7 and 9 hours of sleep per night for optimal health.

 To get quality shut-eye, prioritize good sleep hygiene: Turn off your electronics at least two to three hours before bed, and avoid violent or stressful books or conversations, Lin says.

4. Strive for Mental Balance

Research shows that long-term stress may lead to chronically elevated cortisol levels, which can essentially force your immune system to shut down. While this “shutdown” response is beneficial in the short-term, keeping us healthy until stressful events are over, it’s not helpful for our long-term ability to fight bacteria and viruses.

This is why it’s important to incorporate stress-reduction techniques; the key is to find what works for you. “I like to give my patients options,” says Ben Kaplan, MD, an internal medicine physician at Orlando Health Medical Group Internal Medicine in Florida. He recommends meditation (apps like Headspace and Calm can help), journaling, and any activity that you enjoy, such as fishing, playing golf, or drawing.

Similarly, opportunities to laugh may reduce overall stress, making you less susceptible to illness in the long run, Cherian notes.

 And don’t underestimate the power of nurturing your relationships: Studies have found that social connections may lead to a greater sense of support, thereby reducing stress hormone levels.

5. Stay Current on Vaccinations

Getting regular vaccinations can help support your immune system, bolstering your body’s natural defenses against harmful viruses and bacteria. Without vaccination, it can take your immune system seven to 14 days to organize and launch a full-scale attack against disease-causing pathogens.

“And unfortunately, depending on how much you’re exposed to and whether you’re a healthy young person or a more senior person whose immune response is waning, the end of those 14 days can result in you getting infected or staying healthy,” says LJ Tan, PhD, the chief strategy officer for Immunize.org in Saint Paul, Minnesota.

If you get sick, your immune system will then help bring things back under control so you can recover. But vaccines may shorten that two-week waiting period by letting your immune system engage with a piece of the virus or bacteria.

“We introduce it to your immune system in a very controlled manner, such that it cannot cause infection,” Dr. Tan says. “Once your immune system has gone through this initial stimulation, it generates memory immune cells that have seen the enemy and are ready to go when they see the enemy again.” The official term for this phenomenon is the “anamnestic response.”

In general, memory immune cells eventually die off, and protective antibodies decline over time. With some infectious diseases, you have to reintroduce your body to pathogens with regular vaccination, such as with a booster, to keep your immune system responsive. How often you need a booster will vary depending on the pathogen — for example, the U.S. Food and Drug Administration (FDA) recommends a flu shot every year — so be sure to touch base with your physician.

While vaccines are safe and effective for most people, Tan advises some individuals to consult their healthcare teams before vaccination. That includes people who are immunocompromised because of treatments like chemotherapy and anyone with a history of allergic reactions to vaccines.

6. Make Conscious Hygiene Part of Your Routine

Personal hygiene may not directly improve immune system health, but basic habits like washing your hands, using hand sanitizer, wearing a mask, and staying home when you do get sick can prevent the spread of germs.

“We have this incredible immune system that helps us stay healthy, but if we can avoid challenging that immune system, we’re going to stay healthier in general,” Tan says. “This way, you can also hopefully reduce your exposure to pathogens that we don’t have vaccines for.”

Wash or sanitize your hands after using the bathroom, before and after shaking hands with others, after coughing or sneezing, and after making contact with high-touch surfaces like countertops and door handles.

 “I carry a bottle of hand sanitizer with me everywhere, simply because I’m an infection control expert and I know what the benefits are,” Tan says.
Research shows that hand sanitizers containing 60 percent alcohol can be just as effective for killing germs as washing your hands with soap and water.

 But, of course, handwashing is the gold standard for preventing the spread of germs.

Cover your nose and mouth when you cough or sneeze so you don’t spread your droplets to people around you. Stay home if you do get sick to prevent spreading your germs to others.

7. Avoid Toxins Like Alcohol and Cigarettes

Try to limit or avoid alcohol and quit smoking if it’s a current habit, to support your immune system.

High alcohol consumption is associated with a range of negative health effects, including lowered immune function. When you drink to excess, your body is too busy trying to detoxify your system to bother with normal immune system function, Kaplan explains.

Studies show that chronic heavy alcohol use can lower the levels of immune cells in your body.

 People who drink heavily also face a greater likelihood of pneumonia, acute respiratory syndrome, alcoholic liver disease, and certain cancers.

 If you drink occasionally, limit your alcohol consumption to one to two drinks per day.

Like alcohol, cigarette smoking can affect immune health. “Anything that’s a toxin can compromise your immune system,” Kaplan says. Specifically, the chemicals released by cigarette smoke can interfere with the growth and function of immune cells, like cytokines, T cells, and B cells.

Smoking also worsens viral and bacterial infections (especially those of the lungs, like pneumonia, flu, and tuberculosis) and postsurgical infections.

“Don’t smoke,” Lin says. And avoid secondhand smoke whenever possible. If you currently smoke, there are many resources available to help you kick your habit, including counseling, nicotine replacement products, prescription non-nicotine medications, and behavioral therapy.

8. Keep Symptoms of Chronic Conditions Well Managed

Chronic conditions like asthma, heart disease, and diabetes can affect the immune system and increase your risk of infections.

For example, when people with type 2 diabetes don’t manage their blood sugar properly, a chronic, low-grade inflammatory response can ensue that weakens the body’s defense system.

 Similarly, people with asthma are more susceptible to catching the flu and often experience worse flu and asthma symptoms as a result of the infection.

Properly managing your chronic condition can help free up reserves for your body to fight off infection, Lin says. So, be sure to stay on top of any medications, doctor visits, and healthy habits that keep your symptoms at bay. Your immune system will thank you.

The Takeaway

  • Your immune system is a complex system of skin cells, blood, bone marrow, tissues, and organs that help your body fight off disease-causing pathogens. When it’s not working properly, however, you might be more prone to illness and infection.
  • Keeping your immune system healthy involves a combination of lifestyle and medical changes to improve your overall health. This means eating a balanced diet, getting enough sleep, managing stress, getting daily exercise, and avoiding toxins like cigarette smoke and heavy alcohol consumption.
  • Habits like washing your hands, using hand sanitizer, wearing a mask, and staying updated on vaccinations can help protect your immune system against infection and illness.
  • If you have an underlying chronic health condition, visit your doctor regularly and manage symptoms to improve your body’s immune function.

Resources We Trust

EDITORIAL SOURCES
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Grant Chu, MD, is an associate clinical professor at the David Geffen School of Medicine at UCLA. Dr. Chu is also associate director of inpatient East-West consult services at the UCLA Health hospitals.

He's board-certified in internal medicine by the American Board of Internal Medicine and is a diplomate of the National Certification Board for Acupuncture and Herbal Medicine (formerly the National Certification Commission for Acupuncture and Oriental Medicine).

He received a bachelor's degree in neuroscience from Brown University, where he also earned his medical degree. He has a master's in acupuncture and oriental medicine from South Baylo University and a master's in business administration from the University of Illinois at Urbana-Champaign.

He completed his residency in internal medicine at the University of California in Los Angeles and a fellowship at the Center for East-West Medicine at UCLA. He has held academic appointments at the University of California in Irvine and the University of Queensland in Australia.

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