Originally Posted by
elcruxio
Really since there aren't live viruses or pathogens in the covid vaccines, they shouldn't warrant the same kind of caution in terms of exercise as the actual disease or even a flu or other milder respiratory illness. Just because one might feel sick after a vaccine doesn't mean one actually is.
But if you have a fever, I'd still lay off exercise.
Fever is a systemic inflammatory response, whether from an infection or a vaccine, and strenuous exercise while you have systemic inflammation has been shown to produce scar tissue in your heart. That can lead to a bunch of problems like arrythmia (or worse).
I wouldn't take the chance.