With a global pandemic changing everyday life across the globe, many of us are thinking about our immune health more than, well, ever. From loading up on vitamin C to following safety measures while shopping, we’re doing everything we can to protect our inner defenses.

However, just as doing certain things can have a positive effect on our immune systems, doing other things can negatively impact our bodies, according to functional medicine expert Dr. Jordan Leasure D.C.

In fact, despite our best efforts to boost our defenses, many habits and behaviors we normally don’t think twice about actually undermine our results. Here are seven things you might be doing that can sabotage your immune system—plus easy-to-implement tips for strengthening that inner shield.

1. You Exercise Too Hard, Too Often

As a general rule, regular and consistent exercise is good for the immune system, says Dr. Josh Axe, D.N.M., C.N.S., D.C, member of The Vitamin Shoppe Wellness Council and co-founder of Ancient Nutrition. “Exercise helps promote the circulation of anti-inflammatory cytokines, which help the body fight off infection,” he explains.

Overdoing it on exercise, however, may actually do more harm to the body (and immune system) than good. It’s probably one of the sneakiest ways you may be hurting your immune health.

Read More: Are You Doing Too Much HIIT?

In fact, “high exercise training workloads, competition events, and the associated physiological, metabolic, and psychological stress are linked with […] increased illness risk,” found one 2019 Journal of Sports and Health Science study. The researchers suggest that inflammation caused by extended, high-intensity bouts of exercise may be to blame.

Though some may be tempted to exercise more than usual right now, stick to no more than 60 minutes of exercise five days per week, and limit HIIT to two or three days per week, recommends trainer and dietitian Charlotte Martin, M.S., R.D.N., C.P.T., owner of Shaped by Charlotte.

2. You Underestimate Frozen Vegetables

We get it, grocery shopping can be stressful these days. Your desire to live off of non-perishables and avoid fresh produce runs? Totally understandable.

“Even people who typically eat nutrient dense, well-rounded meals are now resorting to long-lasting pantry foods like mac and cheese and pasta,” says Martin.

However, forgoing produce robs the body of vitamins and minerals essential for immune health. Vitamin C, for example, acts as an antioxidant and fights off inflammation-causing free radicals, explains Martin. Zinc, meanwhile is necessary for the creation of immune cells. 

Ultimately, “any vitamin deficiency limits the immune system’s ability to operate optimally,” she says.

Good news: You can avoid the grocery story and still eat those immune-supporting nutrients. How? During your next grocery haul load up on frozen fruits and vegetables.

Read More: The Nutritionist’s Guide To Canned And Frozen Foods

“There’s a major misconception that frozen fruits and vegetables are less healthy than fresh produce,” says Martin. However, vegetables and fruits are picked at peak freshness (and peak nutritiousness) before being frozen. As a result, “in some cases, frozen foods are actually more nutritious than their fresh counterparts,” she says.

Martin’s go-to frozen veggies: spinach (which is high in iron and zinc) and Brussels sprouts and broccoli (which are both high in vitamin C).

3. You Fall Short On Protein

Animal proteins don’t last long in the refrigerator—and freezer room fills up fast. The result: Carnivores may struggle to meet their protein needs while avoiding supermarkets.

That’s not just a problem for your muscles. According to Martin, the amino acids found in protein are the building blocks of all cells in the body—including immune cells.

That’s where shelf-stable, plant-based proteins like lentils, chickpeas, and black beans come in. “There are plenty of protein-rich options you can incorporate to help your immune system fight infection,” Martin says.

If it’s shelf-stable animal proteins you seek, go for canned salmon and tuna. Both provide omega-3 fatty acids, which can help regulate immune disruption in the body, she adds. Also consider using a protein powder or snacking on protein bars.

To reap the immune benefits of protein, consume at least 0.8 grams of protein per kilogram of body weight per day, says Martin. (That’s 0.36 grams per pound.) A 150-pound person, for example, should aim for a minimum of 54 grams of protein per day.

4. You Don’t Eat Fermented Foods

Probiotics aren’t just for people with digestive woes. They’re also beneficial for anyone looking to do their immune system a solid, says Axe.

“Nearly eighty percent of the immune system is housed in the gut,” he explains. “So, there’s a direct relationship between your gut health and immune health.” Basically, if your gut health isn’t in tip-top shape, your immune system won’t be either.

“Even if you’re not having any noticeable gut troubles, eating probiotic-rich fermented foods (like Greek yogurt, sauerkraut, kimchi, kombucha) is a good bet,” says Axe, who recommends two servings per day. Supplement with a solid probiotic, such as The Vitamin Shoppe brand Ultimate 10+ Probiotics, for additional immune and respiratory health support.

5. Your Sleep Schedule Has Gone Haywire

Though life has completely changed, one pre-pandemic rule still stands: Sleep for at least seven hours per night.

In fact, “getting adequate sleep is more important now than ever,” Leasure says. “Failing to do so can compromise the immune system.” It’s true: One 2012 review published in Pflugers Archive, for instance, linked reduced sleep quality with reduced production of cytokines (proteins that support our immune response).

Read More: Try These Tactics To Get A Decent Night’s Sleep During Times Of Stress

Leasure’s number-one tip for sleeping more: Set a sleep schedule and adhere to it. “Don’t let yourself sleep in or stay up much later on the weekends,” she says.

Having a hard time quieting your mind once you get into bed? Unplug from all technology and TV two hours before you hit the hay (or at least stop reading any news updates).

6. You’ve Been Drinking More Alcohol

Jokes about liquor stores being essential businesses aside, drinking more during quarantine won’t do your body any favors.

Get this: According to one 2017 Progress In Neuro-Psychopharmacology and Biological Psychiatry study, heavy drinking makes the body three-to-seven times as susceptibility to both bacterial and viral infections.

“The immune system is an intricate network of molecules, cells, tissues, and organs that work together to defend the body against infectious agents,” Axe explains. The ethanol in alcoholic beverages alters all of these pathways, making the body less adept at fighting infections.

Not to mention, alcohol also disrupts sleep quality and the gut microbiome, he adds. It’s a triple-whammy for the immune system.

The solution: Stick to the Dietary Guidelines for Americans‘ recommendations (one drink per day for women and up to two drinks per day for men). Better yet, replace your nightly beer or glass of wine with fizzy kombucha.

7. You Smoke

The stress of the current climate makes quitting smoking especially difficult. However, “the research is pretty clear-cut: Smoking is bad for the immune system,” says Axe. One 2016 Oncotarget study, for instance, found that cigarette smoking weakens immunity against infections by eliciting an inflammatory response from immune cells.

Plus, cigarette smoking is also associated with a number of sleep issues, like insomnia, longer sleep latency, and more sleep apneas and leg movements in sleep.

Considering that smoking is also linked to cancer, heart disease, and stroke (you know this!), it’s in your best interest to quit—global pandemic or not.

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