Moderate exercise post-vaccine may provide an immunity boost

Researchers at Iowa State University have found that 90 minutes of mild- to moderate-intensity exercise directly after a flu or COVID-19 vaccine may provide an extra immunity boost.

Antibodies are essentially the body’s ‘search and destroy’ line of defence against viruses, bacteria, fungi and parasites. Vaccines help the immune system learn how to identify something foreign and respond by bolstering the body’s defences, including an increase in antibodies.

The researchers found that study participants who cycled on a stationary bike or took a brisk walk for 90 minutes after getting a jab produced more antibodies in the following four weeks compared to participants who sat or continued with their daily routine post-immunisation. They found similar results when they ran an experiment with mice and treadmills, as published in the journal Brain, Behavior, and Immunity.

“Our preliminary results are the first to demonstrate a specific amount of [exercise] time can enhance the body’s antibody response to the Pfizer–BioNTech COVID-19 vaccine and two vaccines for influenza,” said Kinesiology Professor Marian Kohut, lead author of the paper. During this exercise period, study participants focused on maintaining a pace that kept their heart rate around 120–140 beats per minute rather than travelling a particular distance.

The researchers said the study’s findings could directly benefit people with a range of fitness levels, as nearly half the participants in the experiment had a BMI in the overweight or obese category. They did, however, find that a shorter workout of 45 minutes did not increase the participants’ antibody levels; Prof Kohut said the research team may test whether 60 minutes is enough to generate a response in a follow-up study.

As to why prolonged, mild- to moderate-intensity exercise could improve the body’s immune response, Prof Kohut said there may be multiple reasons. Working out increases blood and lymph flow, which helps circulate immune cells; as these cells move around the body, they’re more likely to detect something that’s foreign. Data from the mouse experiment also suggested a type of protein (ie, interferon alpha) produced during exercise helps generate virus-specific antibodies and T cells.

“But a lot more research is needed to answer the why and how,” Prof Kohut said. “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.”

The researchers are continuing to track the antibody response in the participants six months post-immunisation and have launched another study that focuses on exercise’s effects on people who receive booster shots.

Image credit: Christopher Gannon/Iowa State University.

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