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Worst Habits That Destroy Your Immunity, Doctors Say

Do your immune system a favor and halt these unhealthy habits.

With viruses like COVID-19 (and to a lesser extent, monkeypox) circulating, taking care of immune health has never been more important. "The immune system in the body fights against disease-causing microorganisms, or to put it simply, it protects you against germs, such as bacteria, viruses, fungi and toxins that make us more susceptible to colds, the flu and even coronavirus," says Kenneth Abriola, MD. "The immune system relies on a person's bloodstream and lymphatic system to deliver nutrients throughout the body to get rid of toxins that can harm the body… The best way to keep your immune system strong and keep you healthy, is by living a healthy lifestyle." Here are five habits seriously undermining your immune health, according to experts. Read on—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.


Drinking Too Much Alcohol

drinking beer

Just one session of binge drinking can impact the immune system for up to 24 hours. "Alcohol has negative effects on our innate and adaptive immune cells," says Heather Moday, MD. "Chronic and binge drinking also damages the lining of the gastrointestinal tract, as well as protective T cells and neutrophils in the GI system. This disrupts gut-barrier function and allows leakage of microbes into the blood, resulting in inflammation."



cigarette in man hand with smoke

"Smoking harms the immune system and can make the body less successful at fighting disease," warns the CDC. "The immune system is the body's way of protecting itself from infection and disease; it works to fight everything from cold and flu viruses to serious conditions such as cancer. Additionally, smoking is known to compromise the equilibrium, or balance, of the immune system. This increases the risk for several immune and autoimmune disorders (conditions caused when the immune system mistakenly attacks the body's healthy cells and tissues). New evidence finds that smoking is a cause of rheumatoid arthritis, an autoimmune disease in which the immune system attacks the joints and causes swelling and pain."


Not Enough Sleep

bad sleep

Getting the right amount of quality, restorative sleep is crucial for immune health—one study shows poor sleep can even impact vaccine efficacy. "What we show is that the immune system functions best when it gets enough sleep. Seven or more hours of sleep is recommended for optimal health," says Dr. Nathaniel Watson, co-director of the UW Medicine Sleep Center at Harborview Medical Center. "The results are consistent with studies that show when sleep deprived people are given a vaccine, there is a lower antibody response and if you expose sleep deprived people to a rhinovirus they are more likely to get the virus. This study provides further evidence of sleep to overall health and well-being particularly to immune health."



senior African American man sitting on white sofa in light room in beach house

Loneliness and stress can have a severe impact on the immune system, research shows. "That explains very clearly why lonely people fall at increased risk for cancer, neurodegenerative disease and viral infections as well," says Steve Cole, a genomics researcher at the University of California, Los Angeles. "At this point, my best guess was that loneliness really is one of the most threatening experiences we can have. Though I didn't think of loneliness as being that awful. It's not pleasant, but not something my body should be getting all up in arms about."


A Terrible Diet

Man eating burger
Sander Dalhuisen/Unsplash

Your immune system thrives on a healthy diet, doctors say. "There's no doubt that a healthy diet improves your immunity to illness," says Cassandra Calabrese, DO. "What you put in your body is important for your overall health, including your immune system. I'm a big fan of the Mediterranean diet. It's a great diet for immune health." And to protect your life and the lives of others, don't visit any of these 35 Places You're Most Likely to Catch COVID.

Ferozan Mast
Ferozan Mast is a science, health and wellness writer with a passion for making science and research-backed information accessible to a general audience. Read more about Ferozan