It's true. Getting a flu shot—which mimics the viral infection by causing your immune system to form antibodies and T cells that better prepare you to fight the flu—isn't guaranteed protection from the virus. (And this is true for any vaccine.) Rolling up your sleeve does, however, reduce the severity of flu symptoms (think: fever, chills, muscle aches, cough, congestion, runny nose, headaches, and fatigue) while also helping to ensure that you don't become one of the thousands of people to die from it (sadly, up to 62,000 people were lost to flu infections last year alone).
That said, the flu shot only offers between 40 to 60 percent efficacy, and results vary depending on who is getting it. (And if you're a child, immunocompromised—those with heart disease, diabetes, asthma, chronic obstructive pulmonary disease (COPD)—or over 65, that should definitely include you.)
Luckily, there are ways to boost this percentage—but unfortunately, getting a COVID-19 vaccine isn't one one of them. "Although both the flu and COVID are caused by viruses and have some overlapping symptoms, there is no evidence of the COVID vaccines protecting against influenza," says Venky Soundararajan, PhD, co-founder and chief scientific officer of the biotech information company Nference. Doctors and medical experts still advise everyone eligible to get the COVID-19 vaccine, too, though, since it helps reduce the likelihood of co-infection of flu and COVID—which is entirely possible.
Here are five healthy habits to incorporate into your lifestyle to help make your flu shot even more effective than it already is.
Don't Skimp on Sleep
While one night of compromised sleep won't kill you, it's best to be fully rested the night before you receive your flu vaccine. In fact, make it two nights before. A 2020 International Journal of Behavioral Medicine study revealed that not getting enough Zzzs was linked to fewer infection-fighting antibodies regardless of age or sex.
Sleep helps immunity and more robust immune responses, says Purvi Parikh, MD, an immunologist at NYU Langone Health. While snoozing, your immune system releases a variety of cytokines (proteins), some of which are crucial to fighting infection. Being sleep deprived slows this process, leaving your immune system vulnerable. In fact, getting only four hours of sleep reduced natural killer cells—immune cells that put the kibosh on cells infected with the virus by almost 30 percent.
Schedule Your Shot as Early as You Can
They say the early bird catches the worm—research agrees. In one study, folks who were administered their flu shots in the morning had significantly higher antibodies present a month later than those who received theirs during the afternoon. The month you take your shot also has implications. Dr. Parikh suggests getting it between the end of August and October to provide coverage throughout the flu season, which peaks between December and February.
Kick Up Your Cardio (Regularly and Immediately Post Shot)
It's no secret that breaking a sweat is good for your health. Study after study proves that it beefs up your immune response, lessens your risk of illness and decreases inflammation. Not to mention, a review of data extending back to the 1980s suggests that in addition to increased antibodies, exercise may also cause them to be redistributed, moving to areas more likely to become infected (like your lungs).
"Exercise is a controlled form of stress that stimulates several responses in the body," Alex Rothstein, coordinator of the Exercise Science program at New York Institute of Technology explains. "One of these responses is the deployment of white blood cells and even more directly the deployment of these cells to working and/or inflamed tissue where they may be needed most."
Getting sweaty also revs up the circulatory system that "helps deliver proper nutrients to cells while cleaning up cellular waste, which leads to improved immune system functioning, '' adds Joe Holder, a Nike Master Trainer and a health and wellness consultant. He also notes that exercise has been linked to improved function of specific cells such as natural killer cells within the immune system itself.
Exercise can also help assist in making sure you have quality body composition, explains Holder. Why is this important: "Obesity causes our immune system to become overworked due to being in a state of low-grade inflammation," he explains. "This causes our immune system function to lag a bit so when a real infection is present our body it's slower to respond."
So how much heart-pumping cardio do you need? A full 90 minutes, and make sure it's post needle prick. According to Iowa State research, students who pedaled it out on a stationary bike for 90 minutes shortly after receiving their vaccine were rewarded with double the flu-fighting antibodies when compared with their non-biking counterparts. Also, adults over 60 who engaged in regular cardio not only experienced an uptick in the antibodies necessary to prevent infection, but it lasted throughout the entire flu season, University of Illinois at Urbana-Champaign research reveals.
Dr. Parikh does warn, though, that exercising post shot "may exacerbate or lower the threshold for an allergic reaction." So pay attention to your body and only do what feels right (and talk to your doctor if you have any questions or concerns.)
Lift Some Weights
If you'd rather pump iron than carve out cardio time, you're in luck. When women did bicep curls and side arm raises for 20 minutes, six hours before receiving a dose, focusing on the arm in which they intended to get jabbed, they had more antibodies present after four weeks post shot. Men, however, simply increased their general immune response, but not their flu-fighting protection, explains Robin Lowman White, MD, a board-certified emergency medicine physician based in Atlanta, Ga., who was not a part of the study.
Put on a Happy Face
No, seriously. In a 2018 Brain, Behavior and Immunity journal study, 138 adults between the ages of 65 and 85 had their moods tracked for six weeks—two weeks pre flu shot and one month afterward. What they found was that four weeks post shot, higher flu antibodies were in greater supply in those with a positive outlook on life versus a negative one.
Research in general has also found that a pleasant attitude can strengthen your immune system as well as make it three times more likely that you don't get sick, regardless of virus-type, age, sex, and body mass. Apparently happiness really is the best medicine.