Can you exercise after getting a vaccine?

You know that vaccines can prevent disease—and so can exercise to a certain degree. But can you combine the two? Is it okay to head to Zumba, sweat a few miles out on the treadmill, or lift weights after your flu shot? What about when you’re receiving the COVID-19 or pneumococcal vaccines or, really, any vaccine at all? 

Can I work out after a vaccine?

Medical experts say exercise after vaccines is fine, as long as you’re feeling up to it. In fact, according to a new study published in Brain, Behavior, and Immunity, engaging in light aerobic exercise after a Pfizer-BioNTech COVID-19 vaccine or seasonal influenza vaccine—such as walking or bicycling—can actually improve the body’s immune response by increasing antibody activation. Participants who began exercising at 60-70% heart rate within 30 minutes of vaccination for 90 minutes experienced a more enhanced immune response than both a sedentary control group and a group who exercised at the same intensity for 45 minutes. 

“There is no contraindication [a reason not to do something] to exercising on the day of or the days after you receive a vaccine,” says William Schaffner, MD, a professor of infectious diseases at Vanderbilt University School of Medicine. “But be sensible and listen to your body. Some people respond to vaccines with fatigue, muscle aches, and sometimes a fever. The day you receive a vaccine may not be the day to try and set a personal record.” If you’re up to it, stick with gentle exercise to help maximize the benefits of post-vaccine exercise.

Can exercise after vaccines improve immune response?

If exercise doesn’t hurt your immune response to a vaccine, can it actually help it? Though recently published information about exercising post-vaccination is promising, data from earlier research is mixed. The results can vary depending on the age and gender of study subjects, which vaccines they get, and the type, duration, and timing of the exercise they performed. 

For example, one study looking at healthy young adults found that those who performed 15 minutes of exercise with resistance bands prior to receiving the pneumococcal vaccine had an enhanced antibody response. But the response was only significant in those who received a half-dose of the vaccine, versus a full one. 

Other research published in the journal Frontiers of Immunology found that a single bout of exercise can enhance the immune response to vaccinations in both young and older study subjects. And a research team from the University of Sydney and University of Birmingham suggest that performing moderate-intensity exercise (such as biking) or resistance exercise (such as weight lifting) immediately before or after getting an influenza vaccine may help activate the immune system’s response to the vaccine. However, the benefits were more pronounced in older people than in younger people. 

“Exercise likely increases blood and lymphatic flow, which helps spread the immune cells that are produced post vaccination,” explains Ramsey Shehab, MD, a family practitioner and sports medicine specialist at Henry Ford Health Systems.

Exercise after COVID vaccines

Vaccines help initiate immunity to a certain germ, such as a virus. Because they contain weakened or inactive parts of a virus or bacterium, vaccines trigger the immune system to create antibodies and T-cells—two weapons the immune system uses to recognize and fight foreign invaders. The stronger your immune response to that vaccine, the better protection it offers. So if moderate exercise can boost vaccine efficacy, what’s the best way to do it? 

In one study, women who exercised their deltoid (shoulder) and bicep (upper arm) muscles prior to receiving a flu vaccine had a better antibody response post-vaccination, while men had a better cell-mediated response (an immune response that involves disease-fighting T-cells, but not antibodies). 

Yet another study examined a group of elite athletes and control subjects who were not athletes. Though each group received a flu vaccine and showed a good immune response to the virus post vaccination, those who exercised intensely and regularly (e.g., the elite athletes) had the most pronounced immune response. Those same athletes were studied further. Regardless of when they received their vaccine—either two hours post training or after one day of rest—their immune response (and the number and severity of the side effects they reported) was not significantly different.

The most recent research suggests that it’s safe to exercise after a COVID-19 jab–in fact, it’s recommended. That’s because long-duration cardiovascular exercise like a light jog, brisk walk, or a bike ride can increase your immune response to the COVID-19 or flu vaccine. But when it comes to strenuous physical activity, like weight-lifting or jumping rope, the jury’s still out. And larger-scale studies are needed to determine if similar effects—from say, a 90-minute walk or stationary bike ride—are applicable after a second shot, or COVID-19 booster.

“Be sensible, not obsessive,” Dr. Schaffner recommends. “I encourage exercise to the degree that you can, just because it’s generally a good thing to do.”

COVID vaccine side effects

According to the Centers for Disease Control and Prevention (CDC), the most common side effects of the COVID-19 vaccine are:

• Swelling and pain at the injection site
• Fever
• Headache
• Fatigue
• Muscle aches
• Nausea
• Chills

Most side effects of the vaccine last one to three days and are likely to be more pronounced after receiving your second dose of the vaccine (although more than 50% of people in the vaccine clinical trials didn’t have any side effects). 

Serious side effects are rare. A medical professional will observe you for 15-30 minutes immediately after receiving your COVID-19 vaccine to make sure you don’t have a severe allergic reaction to the shot. While the numbers are few, cases of severe symptoms such as myocarditis (an inflammation of the heart muscle) and pericarditis (an inflammation of the outer lining of the heart) have been reported with COVID-19 vaccination, mostly among young men. “It’s a very small number [who get COVID-19 vaccine-related myocarditis], but using some caution post covid vaccination in young people may be warranted,” Dr. Shehab says. 

Vaccines affect different people differently, and the COVID-19 vaccine is no exception. While there’s no reason you can’t exercise after COVID vaccines, you may not feel like it. Though there aren’t known risks associated with exercising after a COVID-19 vaccine, feeling lousy will make it tougher to exercise. If you’re experiencing symptoms like fatigue, muscle aches, fever, nausea, or chills, it’s probably a good idea to take it easy and allow yourself to recover.

When to see a doctor for vaccine side effects

Most side effects from vaccines—headache, muscle/joint pain, tiredness, fever, and pain where the injection was given—are mild and short lived. Severe allergic reactions are extremely rare (occurring in about one to two people per 1 million who receive vaccines). But get immediate medical attention if you’re having any of the following:

• Difficulty breathing
• Swelling of your face or throat
• Dizziness/weakness
• Rash or hives on your body
• Fast heartbeat

It’s no secret that the health benefits of physical activity are numerous. Moderate-intensity exercise may provide an extra immune boost that results in a reduced risk of contracting colds and upper respiratory infections. And staying active may be protective against severe COVID-19 outcomes. In a recent study of 48,440 Californians who developed COVID-19, those who exercised regularly were 50% less likely to require hospitalization than those who were inactive. But in the end, don’t forgo a vaccination because you think it might affect your workout schedule or your physical performance. What’s more, overdoing it with too much vigorous exercise can actually suppress your immune system. And that’s a bad thing, because it puts you at increased risk of getting sick.

It’s important to remember that healthy, active people get sick, too. “Just because you may be young, healthy, and physically fit does not mean a virus like COVID cannot make you seriously sick,” Dr. Shaffner says. “We see it every year with the flu and now we’re seeing it with COVID—young, strong people being brought into the hospital and the intensive care unit [with these viruses]. Just being healthy is not enough to ward off a virus.” The bottom line? Get your vaccinations.