Most flu vaccines are administered by injection into the deltoid muscle, so it is generally considered sensible to avoid strenuous upper body exercise for several hours after vaccination. In most cases, it’s totally OK to work out after your flu jab, as long as you’re feeling well enough.
Whether you feel well enough to exercise after your flu jab vaccine depends on which side effects, if any, you experience. Side effects do vary person to person and so it is important to trust your gut and listen to your body. Some people may experience a stronger response to the vaccine and require a few days rest before feeling able to exercise again, whilst others may be fine after a couple of hours. Side effects are a sign your immune system is responding to the vaccine and they shouldn’t last beyond a few days – talk to your doctor if they last longer.
Our recommendation is that when you feel ready to go, do so but take it easy. Drink plenty of fluids and perhaps do a gentler version of your standard workout. You can resume your usual gym routine when you are feeling completely better.
The bottom line: It’s definitely OK to exercise after you get a flu jab so long as you feel up to it. Just let your body be your guide and scale things back as needed.