The immune system is your ever-present bodyguard, an elaborate natural software program that protects you, 24-7, against illnesses large and small. But even during the COVID-19 pandemic, it’s easy to forget that the immune system doesn’t operate in complete independence. There are things we do everyday that can help it do its job—or undermine it. These are the common habits that strengthen immunity, according to experts. Read on to find out more—and to ensure your health and the health of others, don’t miss these Sure Signs You Have “Long” COVID and May Not Even Know It.


Several studies have found that Americans have been imbibing more alcohol to cope with the stresses of the pandemic. Unfortunately, that’s exactly what you don’t want to do if you want to strengthen your immune system. For years, scientists have warned that excessive drinking can weaken your immunity—a message that is more urgent today. “Alcohol consumption is associated with a range of communicable and noncommunicable diseases and mental health disorders, which can make a person more vulnerable to COVID-19,” said the World Health Organization in April 2020. “In particular, alcohol compromises the body’s immune system and increases the risk of adverse health outcomes.” To avoid that, drink moderately—meaning no more than two drinks a day for men and one for women—or abstain.

Young woman walking on beach

Exercise is a powerful immune-system booster. According to the National Institutes of Health, exercise can flush bacteria out of the lungs and airways, which may reduce your chances of coming down with colds and flu; cause antibodies and white blood cells to circulate more rapidly through the bloodstream, potentially neutralizing disease-causing invaders faster; and slow the release of stress hormones, which are known to impair immunity. 

The good news: You don’t have to start training for a marathon. You can realize these immune-boosting benefits from a moderate amount of exercise, even walking 20 minutes a day.

vitamin d

More than 40% of Americans have insufficient blood levels of vitamin D, and that’s bad news for your immune system. Take it from the nation’s top infectious disease expert, Dr. Anthony Fauci, who takes a daily vitamin D supplement. “If you’re deficient in vitamin D, that does have an impact on your susceptibility to infection,” he said in an interview last fall. “I would not mind recommending—and I do it myself—taking vitamin D supplements. There is good evidence that if you have a low vitamin D level, that you have more of a propensity to get infected when there are infections around.”

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Relaxed happy young man resting having nap on comfortable couch breathing fresh air

“Try to avoid or alleviate severe stress, which we know can sometimes impact the immune system,” advised Fauci last fall. Chronically being stressed out causes the brain to produce more of the stress hormone cortisol, which has a number of negative physical effects, including weakened immunity. According to the American Cancer Society, people who experience chronic stress are more prone to the common cold and viral infections like the flu.

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Pretty young woman on bed in modern apartment smiling after wake up

While you’re cutting back on stress, make sure you’re chilling out enough to get sufficient shut-eye every night. Sleep is when a variety of major body systems rest and reboot—including the heart, brain and immune system. A growing body of research has linked poor-quality sleep to a wide range of serious illnesses, including cancer, heart disease, and dementia. To keep your immunity in top shape, experts such as the National Sleep Foundation recommend that adults get seven to nine hours of quality sleep every night. And to get through this pandemic at your healthiest, don’t miss these 35 Places You’re Most Likely to Catch COVID.