Contrary to the general belief that avoiding exercise within a few days after a Covid shot is safe, a new study suggests that one 90-minute exercise session can boost immune response in people who have just taken a flu or COVID-19 vaccine. The study by Dr Marian Kohut, professor of kinesiology at Iowa State University’s Navovaccine Institute, and her team, found that a single episode of light or moderately vigorous activity after a flu or COVID-19 vaccine shot increased antibodies up to 4 weeks. The study also found that exercise does not appear to increase adverse effects from a shot.