Dear Dr. K –
Should I skip exercising on the day I get my allergy shot? Aerobic exercise? Weight/resistance exercise?
The simple answer is “No”, but you know I love to palaver, so here’s the long answer!
First off, Americans in general do not get any or adequate exercise so I don’t want to contribute to unhealthy behavior. By the way you posed your question I suspect you might have been a girl scout and learned field expediencies for snake bite. Part of that tutelage is “lie still and especially don’t run”. The reason for that admonition is increased cardio-blood flow would circulate the venom more quickly.
But that snake wisdom does not pertain to allergy shots. These are administered subcutaneously and not intramuscularly. Thus, using your muscles either aerobically or with weights does not impact the shot. Some people experience mild awareness that they received their shot in terms of some local itching/warmth. The adrenal release of extra cortisol and adrenaline that occurs with exercise can abrogate this.
With respect to intramuscular shots such as pneumonia, tetanus and flu, it is still ok to exercise the recipient arm but best done in moderation for a day or two.