Exercising right after vaccination can boost immune response

New research from Iowa State University has found that a prolonged bout of moderately intense exercise after vaccination against COVID-19 or influenza can amplify the body’s immune response. The study showed that 90 minutes of exercise immediately after vaccination increased antibody responses four weeks later.

The relationship between exercise and overall health is so obvious that it’s hardly worth mentioning. But research into exactly how exercise improves our health has produced some fascinating studies in recent years, from how exercise helps the body kill cancer cells to the anti-inflammatory proteins released during physical activity that can prevent cognitive decline.

More specifically, the association between Physical activity and the immune system. has been of particular interest to researchers in recent times. A massive meta-analysis last year analyzed data from several studies involving more than half a million people and found that regular exercise significantly reduced a person’s risk of contracting an infectious disease.

This new study set out to determine very specifically whether individual exercise sessions can influence the efficacy of vaccination. To investigate this question, the researchers recruited several healthy subjects who were about to be immunized with one of three different vaccines (2009 H1N1 pandemic flu, seasonal flu, or COVID-19).

Each subject was randomly assigned to one of three groups: a no-exercise control, or 45 minutes or 90 minutes of moderate exercise that began within half an hour of receiving the vaccine. All participants had blood samples taken before the vaccine, then two and four weeks later, to track the effects of exercise on antibody levels.

Subjects who performed 90 minutes of exercise after vaccination showed statistically significant increases in antibody levels several weeks later compared to the non-exercise group. Interestingly, the researchers detected no difference in antibody levels between the control and 45-minute exercise groups.

An experiment in mice showed similar differences in post-vaccine antibody boosts between 45-minute and 90-minute exercise sessions. The researchers hypothesize that differences in immune responses between the 45-minute and 90-minute exercise sessions offer clues as to how physical activity might drive vaccine-induced antibody responses.

Previous studies have shown that longer durations of exercise generate different types of immunological effects. In particular, the researchers target specific immune proteins called interferon alpha (IFN-α), which had previously been found to increase in relation to exercise duration.

Exercise-induced increases in IFN-α are hypothesized to be one of the possible mechanisms that could explain how physical activity can stimulate antibody responses. However, Marian Kohut, lead author of the new study, says that several different mechanisms are likely playing a role in the new findings.

“…much more research is needed to answer why and how,” Kohut said. “There are so many changes that take place when we exercise: metabolic, biochemical, neuroendocrine, circulatory. So there is probably a combination of factors contributing to the antibody response that we found in our study.”

The researchers note that more work will be needed to determine the optimal type of exercise and duration needed to enhance response to the vaccine. So while 45 minutes of activity may not have been enough here, perhaps 60 minutes could be effective.

Participants in the study used a number of different exercise interventions, from brisk walking to stationary cycling. The main focus was on exercise intensity, with all participants required to maintain a heart rate of around 120 to 140 bpm. This rate of exertion is feasible at a range of different fitness levels, the researchers say, and there is no evidence that post-vaccination exercise increases adverse vaccine side effects.

“The exercise intervention is feasible for people who regularly exercise at light intensities, such as walking, and people with a variety of health characteristics were able to complete the exercise,” the team wrote in the study. “For example, nearly half of the participants in the COVID-19 vaccination trial had a BMI in the overweight or obese category, and the distance walked in 90 minutes ranged from about four miles (6.4 km) to over 10 miles (16 km), representing a range of fitness levels, as heart rate and relative perceived exertion level remained within a consistent range.”

The new study was published in the journal Brain, Behavior and Immunity.

Fountain: Iowa State University