You would think so but have never even felt light headed. I found it myself when checking blood pressure at home. My doctor sent me to Emergency, lots of tests and cardiologist recommended a Pacemaker (the normal response to Bradycardia). Having never felt any symptoms I refused. As of July 18 it will be 2 years since I received the injection that caused this. I must admit, if I did experience the onset of light headedness/fainting I would revisit the pacemaker. Best wishes, Dave