As reported in Brain, Behavior, and Immunity, participants who cycled on a stationary bike or took a brisk walk for an hour-and-a-half after getting a jab produced more antibodies in the following four weeks compared to participants who sat or continued with their daily routine post-immunization…

“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,” says lead author Marian Kohut, kinesiology professor at Iowa State University.

The study’s findings could directly benefit people with a range of fitness levels, the researchers say. Nearly half of the participants in the experiment had a BMI in the overweight or obese category. During 90 minutes of exercise, they focused on maintaining a pace that kept their heart rate around 120–140 beats per minute rather than distance.

The researchers also tested whether participants could get the same bump in antibodies with just 45-minutes of exercising. They found the shorter workout did not increase the participants’ antibody levels…

As to why prolonged, mild- to moderate-intensity exercise could improve the body’s immune response, Kohut says 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.

The “how and why” will no doubt be sorted out eventually. The result speaks for itself.