Exercise may boost your vaccine response
Studies find working out amplifies immune response to flu shot
If you are an athlete, you may gain greater immunity from a flu shot than people who are less active, according to two complementary new studies of exercise and vaccinations. The two studies, which involved the same group of elite athletes, suggest that intense training amplifies our vaccine response, a finding with particular relevance now, as the flu season looms and scientists work to develop a COVID-19 vaccine.
In general, exercise aids immunity, most science shows. People who work out often and moderately tend to catch fewer colds and other viruses than sedentary people. If you exercise your arm in the hours before a flu shot, you likely will develop a stronger antibody response, a few small studies indicate.
But there have also been suggestions that under certain circumstances, exercise may dampen the immune response. Some epidemiological research and personal stories from athletes hint that intense, exhausting exercise might be detrimental to immunity in the short term.
The upshot, though, is that many questions have remained unanswered about whether and how strenuous workouts
affect immunity and our bodies’ ability to respond favorably to a vaccination.
So, for the new studies, scientists from Saarland University in Germany and other institutions recruited 45 fit, young, elite athletes, male and female. Their sports ranged from endurance events, like the marathon, to power sports, including wrestling and hammer throw, to team sports, such as basketball and badminton.
For the first experiment, which was published in January in Brain, Behavior, and Immunity, the researchers hoped to establish whether being an athlete and having an athlete’s outsized fitness would goose or impede the young people’s immune reaction to a flu shot. The
scientists recruited an additional 25 young people who were healthy but not athletes to serve as a control group. They drew blood from everyone.
Afterward, all of the young people received a flu shot and kept notes about any side effects they felt. The groups returned to the lab for follow-up blood draws a week, two weeks and six months after the vaccination. Then the researchers checked their blood for anti-influenza immune cells and antibodies.
They found significantly more of those cells in the athletes’ blood, especially in the week after the shot, when everyone’s cellular reactions peaked. The athletes showed a “more pronounced immune response,” says Martina Sester, an immunologist at Saarland University and study co-author.
But those results did not look at the acute effects of exercise and whether a single, intense workout might alter the body’s reactions to a vaccine. So, for the second study, which was published in July in Medicine & Science in Sports & Exercise, the scientists returned to the same data, but focused on the immune reactions of the athletes.
They compared the numbers of immune cells and antibodies in those athletes who got their flu shot within two hours of their most recent training session against those of athletes whose shot had come a day after their last workout. If intense training blunted immune reactions, then the first group of athletes would be expected to show fewer new immune cells. But the researchers found no differences. A strenuous workout beforehand had not lowered — or boosted — the response.
Together, the studies tell us that being in shape is likely to increase our protection from a vaccination, Sester says.
Sester believes even more casual, recreational athletes are likely to mount better flu-vaccine responses than sedentary people. Likewise, she and her colleagues expect high fitness should improve immune responses to other vaccines.