Here's when exactly you should walk after your vaccine—and how long you need to do it for—to reap the full protective benefits.
A woman running with 3 covid vaccine bottles in the background
Credit: Getty Images / Brothers91 / Basilico Studio Stock

Whether it's your first shot or will be your fourth, prepping for success can make the experience a lot easier—and more effective. (ICYMI, the CDC recommends the first COVID-19 booster 5 months after your second shot, and that booster might begin to wane in effectiveness about 4 months later, so chances are we'll all be needing a dose soon.)

We've covered what to eat before and after your vaccines, and what to bring to your vaccine appointment to help things go safely and smoothly. And now, thanks to new research from Iowa State University, we'd like to add one more to-do to your list: Pack your sneakers and block your calendar for a quick sweat session. According to a study set to be published in the May 2022 edition of the journal Brain, Behavior, and Immunity, compared to those who sat or just went about their days post-dose, mild- to moderate-intensity exercise—like a brisk walk or spin on a stationary bike—for 90 minutes performed about 30 minutes after getting a shot can amplify our antibodies for 4 weeks.

As a refresher, antibodies are our body's innate "armor," or our first line of defense against invaders like parasites, fungi, viruses and bacteria. Vaccines work by helping the immune system identify what is foreign—and mount a counterattack by increasing antibodies to attack the outsiders. (By the way, exercise is just one of four things that can make the flu shot more effective.)

To put this hypothesis to the test, kinesiology professor and study lead author Marian Kohut, Ph.D. and her team gave participants who could safely exercise one of two influenza vaccines or the Pfizer-BioNtech COVID-19 vaccine. They asked them to exercise 30 minutes after the vaccine administration, then measured their antibodies at different times. While 45 minutes didn't do the trick, it appears that 90 minutes of exercise—remember, this can be as doable as a walk in the park—appears to be the sweet spot. During those 90 minutes, the individuals were instructed to maintain a steady pace and heart rate rather than worry about distance or speed. In the future, Kohut and co. hope to test if 60 minutes might also be enough.

"Our preliminary results are the first to demonstrate a specific amount of time can enhance the body's antibody response to the Pfizer-BioNtech COVID-19 vaccine and two vaccines for influenza," Dr. Kohut tells Iowa State University News Service.

So what, exactly, is happening behind the scenes? Physical activity increases blood flow and lymph flow, which helps immune cells circulate through the body. As these immune cells tour more rapidly from head to toe, they're more likely to spot something that's foreign.

The researchers also recreated this study among a cohort of mice, and learned that a certain protein called "interferon alpha" that's made during exercise helps the body make more virus-specific antibodies and T cells (or immune cells).

"A lot more research is needed to answer the why and how. There are so many changes that take place when we exercise—metabolic, biochemical, neuroendocrine, circulatory. So, there's probably a combination of factors that contribute to the antibody response we found in our study," Kohut adds to Iowa State University News Service.

In the meantime, the researchers are tracking the antibody response in their current participants for 6 months after their shots, and have started a new study about exercise and booster shots. As they gather more information, it certainly can't hurt to carve out some time for a low-intensity workout after your next vaccine. Study up on our five walking form pro tips before you hit the road, and use Reese Witherspoon's ultra-motivating music mix to keep you moving and grooving for all 90 minutes.

The situation surrounding COVID-19 continues to change quickly; it's possible that information or data has changed since publication. While EatingWell is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations by using the CDC, WHO and their local public health department as resources.