6 Possible Reasons Why You Keep Getting Sick

When the season changed from summer to fall, you caught your usual cold…then you came down with a stomach bug…and then you got hit with the winter flu. It’s like you can’t catch a break—and all you can catch is every illness that’s going around.

Ever wonder why some people sail through life as though protected by an invisible sickness shield, while others get taken down by every passing germ? It’s not just luck of the draw. According to wellness experts, multiple underlying factors can contribute to feeling under the weather over and over. And, fortunately, you can take action to stop the vicious cycle. Here’s why you keep getting sick, and how to finally make it more than a few weeks without coming down with something. 

• ABOUT OUR EXPERTS: Pamela Tambini, M.D., is a board-certified medical internist and chief medical director at The Good Life Treatment Center. Katherine Maslen, N.D., is a naturopathic doctor and host of The Shift Podcast. Christiane Matey, M.S.H.S., R.D.N., L.D.N., A.B.A.A.H.P., is an integrative dietitian and founder of The Mint Nutrition.

1. Your Sleep Is Suffering 

As we all know, sleep is a time of restoration and healing. When we don’t get enough, all sorts of bodily systems suffer, including the immune system. One example of how: “Deep sleep is when your body produces immune-supporting proteins called cytokines, so skimping on rest leaves you more vulnerable to illnesses,” says Pamela Tambini, M.D., board-certified medical internist and chief medical director at The Good Life Treatment Center. Research from 2021 found that even just a few nights of poor sleep can weaken your defenses.

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If you’re constantly getting sick, improving sleep should be the very first thing you work on, suggests naturopath Katherine Maslen, N.D., host of The Shift Podcast. Aim for seven to nine hours per night by sticking to a regular bedtime, avoiding electronics before bed, and keeping your bedroom comfortably cool. “Cutting out caffeine and working on stress may also be helpful,” she adds.

2. You Have a Nutrient Deficiency

Though we may only need small amounts of micronutrients (hence the “micro” in their name), these vitamins and minerals have a powerful impact on our immune system. If you’re constantly down with one bug or another, it might be a sign that certain nutrient levels are too low.

Some of the most common potential culprits here might include vitamin D, vitamin C, zinc, iron, folate, and vitamin A, says Christiane Matey, M.S.H.S., R.D.N., L.D.N., A.B.A.A.H.P., an integrative dietitian and founder of The Mint Nutrition. Each of these nutrients is involved in the delicate dance of immune health. 

Too little zinc, for example, impairs the immune system’s ability to make neutrophils (a type of white blood cell) and fight viruses. Low vitamin D, meanwhile, is tied to all sorts of poor immune health outcomes—likely because it helps the body rid itself of pathogens. “Those with lower vitamin D during the COVID-19 pandemic had higher mortality rates,” she points out. “We also know that low vitamin D leaves us more susceptible to colds and the flu.” 

The solution: Ask your healthcare provider to check your micronutrient levels, then discuss whether supplementation is right for you based on the results. Depending on your unique needs, you might opt for a daily high-potency multivitamin or a higher dose of a single nutrient. For example, some studies have found that 4,000 IU of vitamin D3 without sun exposure or 2,000 IU plus 12 to 15 minutes of midday sun is optimal for maintaining healthy levels. However, your needs will depend on your individual levels.

3. You’re Overdoing It on Processed Foods 

Your diet might hold the key to illness prevention on a more “macro” level, too. Increasingly, research shows that ultra-processed foods—the kinds that undergo considerable alterations from their natural form by the time they get to your mouth—are no friend to immunity. The reason? “Fried foods, sugar-laden foods, or foods loaded with salt, preservatives, and artificial ingredients can create inflammation,” Matey says. In fact, a 2024 study reported that these foods were linked with an increased risk of diseases driven by immune dysregulation, such as inflammatory bowel disease. Other research has linked an ultra-processed diet and the resulting oxidative stress with increased susceptibility to viruses. 

Flip the script on sickness by freshening up your eating plan. Limit the highly processed stuff and plan meals around whole foods. “A diet abundant in nutrient-dense foods, including lean meats, fish, eggs, vegetables, fruits, grains, beans, and fermented foods can help keep us healthy,” Matey says. If you need some help changing your ways, check out this guide to nixing highly-processed foods in just two weeks.

4. Your Stress Is in Overdrive

It’s probably no surprise that periods of heightened stress can make you more susceptible to illness. But you may also want to keep tabs on chronic underlying stress, even if it feels low-grade. “Chronic stress raises cortisol levels, which, over time, can suppress immune function,” says Tambini.

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“If stress is a constant in your life, consider practices like mindfulness meditation, yoga, or regular walks in nature to help lower cortisol levels,” says Tambini. “Reducing stress has a direct and positive impact on your immune health.” Of course, only you can know which activities are truly best at helping your nervous system decompress, so take some time to identify them—and then commit to incorporating them into your day.

5. Your Gut Microbiome Needs Some Love

If it seems like everything these days comes back to your gut…well, you might be onto something. “The gut is one of the most important ecosystems in the body,” Matey explains. “It is estimated that 70 percent of our immune system resides there.” Common signs of gut dysbiosis (a.k.a. an out-of-whack digestive system) include constipation, bloating, and fatigue—but an imbalanced gut microbiome can also leave you more vulnerable to every passing illness.

Folks experiencing digestive symptoms along with a propensity to get sick all the time should see their healthcare provider to get to the root cause of dysbiosis, suggests Matey. In the meantime, try sprucing up your gut health by adjusting what’s on your plate. “Probiotic-rich foods like yogurt, kefir, and fermented vegetables, as well as fiber-rich foods like fruits, vegetables, and whole grains can help maintain a healthy gut microbiome,” says Tambini. If you struggle to down ample amounts of these foods, you might consider a probiotic supplement to increase levels of beneficial bacteria or a fiber supplement to keep digestion moving and your gut microbiome well-fed.

6. Your Environment Is Filled with Germs

What do teachers, nurses, retail associates, and transportation workers have in common? Exposure to lots of people—many of whom may be carrying illness. “Frequent exposure to crowded environments, whether at school or work or on public transportation, increases the likelihood of contracting germs,” says Tambini. It is particularly common for your immune system to take a hit if you’ve just started working at (or otherwise frequenting) crowded places like these.

You might not be able to change the conditions of your environment, but you can take charge of your own behaviors. “Wash your hands frequently with soap and water, especially after being in public spaces,” Tambini recommends. “Avoid touching your face, as this is one of the easiest ways germs enter your body. Regularly cleaning high-touch surfaces at home or work can also reduce exposure to pathogens.”