Exercise after COVID-19 vaccine may increase antibodies, study finds

AMES, Iowa - Going for a long jog or taking a brisk walk could increase the benefits of the COVID-19 shot, a new study finds.

The findings, published in Brain, Behavior and Immunity, demonstrate that 90 minutes of exercise after immunization of the vaccine increases antibody response several weeks later across several models.

According to the study’s researchers, a total of 68 people were included in the final analysis, which analyzed the effects of exercise on different influenza vaccines or the COVID-19 vaccine. In addition, 75 mice were included in experiments to determine the minutes of exercise required to increase antibody response to the influenza vaccine.

In the experiments involving the COVID-19 vaccine, participants were randomly assigned to 90 minutes of outdoor exercise — brisk walking or jogging depending on the fitness level of the person. All participants were asked to avoid exercise on the day the second vaccine dose was given.

A jogger running outdoors. (Photo by Alexander Hassenstein/Getty Images)

The exercise sessions were supervised by research personnel, and routes were designed to monitor heart rate and perceived exertion (RPE) approximately every 10 minutes. An exercise heart rate in the light-to-moderate zone of approximately 120–140 beats per minute or 60-70% of age-predicted maximal heart rate was targeted.

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The exercise sessions began within 15 to 30 minutes after receiving the Influenza or COVID-19 vaccine. The mice ran on a treadmill for either 45, 90, or 180 minutes, and mice also began the exercise session within 15 to 30 minutes after receiving the vaccine.

According to the researchers, nearly half of the participants in the COVID-19 vaccination trial had a BMI in the overweight or obese category, and the distance covered in 90 minutes ranged from approximately four miles to over 10 miles, representing a variety of fitness levels. 

Blood was collected from human participants and mice prior to immunization and at two or four weeks post-immunization. In COVID-19 studies, two doses of the vaccine were given, three weeks apart, and the researchers collected blood before the first vaccine, two weeks after the first vaccine and one week after the second vaccine. 

90 minutes of exercise produced antibodies

The study found that people who exercised for 90 minutes right after their shot produced more antibodies than people who did not. The exercise performed after the jab did not appear to increase side effects.

"It was very interesting that 90 minutes of exercise increased antibody response to three different vaccine formulations in humans (across a range of fitness levels, in normal weight or overweight/obese adults), and 90 minutes of exercise was also optimal in mice," Marian L. Kohut, a researcher and author of the study told FOX Television Stations Group.

Yet, 45 minutes of exercise was not enough

The authors said it will be essential to determine the length of time post-vaccination for which an exercise-associated increase in serum antibody may be present, and longer-term antibody response will need to be assessed.

"Unfortunately, the 45-minute exercise condition was not sufficient to increase antibody response," Kohut continued, adding "However, the 45-minute exercise condition was only tested with influenza vaccine, not with COVID-19 vaccine, so we cannot draw conclusions with respect to 45 minutes of exercise and COVID-19 vaccine." 

Kohut said further research will be essential to test time points between 45 and 90 minutes to determine whether an exercise of 60 or 75 minutes would also be effective.

"This is an important question, as many people may prefer to exercise for only 60 minutes instead of 90 if 60 minutes were to be effective," she added. 

Study limitations include not knowing how long the exercise-associated increase in antibodies lasts after immunization. 

Ongoing studies with the COVID-19 vaccine and COVID-19 booster vaccine are currently being conducted to determine whether the effect is still present at six of 12 months post-immunization.

Exercise prior to COVID-19 vaccine has shown mixed results

According to the researchers, this is currently the only known study to specifically test 90 minutes of exercise in adults just after immunization, as most studies in humans have evaluated exercise prior to vaccination, and the findings are mixed.

In one study, 40 minutes of aerobic exercise prior to immunization was tested, and the study found no benefit of exercise with respect to the antibody response to Influenza H3N2, but a modest enhancement of antibody response to influenza H1N1, only in women, not men. 

Other studies have examined other types of exercise (weight lifting types of exercise or different combinations of exercise) but the results are conflicting, as sometimes a benefit is observed and other times there is no benefit of exercise.

However, the new findings echo other evidence that physical activity may still help our bodies better respond to infections like the flu or COVID. 

One study published last year in the British Journal of Sports Medicine found that physical inactivity was associated with a higher risk for severe COVID-19 outcomes.

The researchers found that patients with COVID-19 who were consistently inactive had a greater risk of hospitalization or death than those who were doing some physical activity.

This story was reported from Los Angeles.