3. Get Plenty of Good Quality Sleep
Your body heals and regenerates while you sleep, making adequate sleep critical for a healthy immune response, Lin says. More specifically, sleep is a time when your body produces and distributes key immune cells like cytokines (a type of protein that can either fight or promote inflammation), T cells (a type of white blood cell that regulates immune response), and interleukin 12 (a pro-inflammatory cytokine), according to a review published in Pflugers Archiv European Journal of Physiology.
When you don’t get enough sleep, your immune system may not do these things as well, making it less able to defend your body against harmful invaders and making you more likely to get sick. One study published in the July–August 2017 issue of Behavioral Sleep Medicine found that compared with healthy young adults who did not have sleep problems, otherwise healthy young adults with insomnia were more susceptible to the flu even after getting vaccinated.
Sleep deprivation also elevates cortisol levels, 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.”The National Sleep Foundation recommends all adults get at least seven hours of sleep per night to optimize health. To ensure you get quality sleep, prioritize good sleep hygiene: Turn off the electronics at least two to three hours before bed, and avoid violent or stressful books or conversations, Lin says.
4. Exercise Regularly (Outdoors, When Possible)
Regular exercise lowers your risk of developing chronic diseases (like obesity, type 2 diabetes, and heart disease), as well as viral and bacterial infections, according to a review in Frontiers in Immunology in April 2018.
Exercise 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,” Lin says. And while there is some evidence that very long or intense exercise sessions may suppress the immune system, making you more susceptible to illness and infection in the hours immediately after your workout, the evidence on that question is contradictory, according to the same Frontiers in Immunology review.
And there is a wealth of epidemiological evidence (studies that followed human behavior and outcomes) showing that people who are more active overall tend to have lower incidences of both acute illnesses (like infections) and chronic ones (like cancer and type 2 diabetes). Studies that have looked at how exercise affects the body on a cellular level suggest that bouts of physical activity may make your immune system more vigilant by distributing immune cells throughout your body to look for damaged or infected cells, according to that 2018 report.
At a minimum, try to meet the physical activity guidelines outlined by the Centers for Disease Control and Prevention (CDC). Adults should be getting at least 150 minutes (two and a half hours) of moderate-intensity aerobic exercise (like walking, jogging, or cycling) or 75 minutes (one hour and 15 minutes) of high-intensity aerobic exercise (like running) every week. You should also be doing strength training at least twice a week. Note: More activity has been found to be linked to even more health benefits, so aim high.
For even more immune system benefits, Dr. Kaplan recommends taking your exercise outside. Spending time in nature has been shown to support mood, lower blood pressure, reduce inflammation, and support immune system health, according to Lin.Sunshine also boosts vitamin D in the body, which plays a key role in immune health, too.
When It Comes to Alcohol, Practice Moderation
Drinking high amounts of alcohol is associated with a range of negative health effects, including lowered immune function. When you drink high amounts of alcohol, your body is too busy trying to detoxify your system to bother with normal immune system function, Kaplan explains. According to a review published in the journal Alcohol Research in 2015, high levels of alcohol consumption can weaken your body’s ability to fight infection and slow down your recovery time. As a result, people who drink high amounts of alcohol face a greater likelihood of pneumonia, acute respiratory distress syndrome, alcoholic liver disease, and certain cancers, according to the same review. If you don’t already drink, don’t start. If you drink occasionally, limit your alcohol consumption to one drink (equivalent to a 4-ounce glass of wine) per day if you’re a woman, and two drinks per day if you’re a man, as recommended by the NIH.
6. Don’t Smoke Cigarettes
Like alcohol, cigarette smoking can also affect immune health. “Anything that’s a toxin can compromise your immune system,” Kaplan says.In particular, the chemicals released by cigarette smoke — carbon monoxide, nicotine, nitrogen oxides, and cadmium — can interfere with growth and function of immune cells, like cytokines, T cells, and B cells, according to a November 2016 review in
Oncotarget.
Smoking also worsens viral and bacterial infections (especially those of the lungs, like pneumonia, flu, and tuberculosis), post-surgical infections, and rheumatoid arthritis (an autoimmune disease in which the immune system attacks the joints), according to the CDC.“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, according to the CDC.
7. Keep Symptoms of Chronic Conditions Under Control
Chronic conditions like asthma, heart disease, and diabetes can affect the immune system and increase risk of infections.For example, when people with type 2 diabetes don’t manage their blood sugar properly, this can create a chronic, low-grade inflammatory response that weakens the body’s defense system, according to an October 2019 review in Current Diabetes Reviews.
Similarly, people with asthma are more susceptible to catching — and even dying from — the flu, and often experience worse flu and asthma symptoms as a result of the infection, according to a study published in the July 2017 issue of the Journal of Allergy and Clinical Immunology.
Living with a chronic condition can be like trying to drive a car that has only three tires, Kaplan says. “If you get sick with a virus, it’s going to take more effort for your body to recover,” he explains.If you manage your chronic conditions better, you'll free up more reserves to help your body 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.