heart rate on beta blockers

I  am on a beta blocker and how do I know the excersise level I reach since heart rate is so slow?  Also, how much do beta blockers reduce the output of the heart or how much does it affect the Ejection Fraction?

Thanks, Tony


This discussion is related to Re: Relation between EF and cardiac output.

[ed34]

Very good questions, ones which I have often wondered myself. You would think that if the heart is continually restricted during exercise that it would adapt, to increase EF. However, after being on beta blockers for nearly three years, this didn't seem to be the case with me but I was hardly doing intense exercise routines in that time. How much beta blockers slow your heart depends on the brand and dosage. On 1.25mg of bisoprolol my resting rate was 68 and I found it impossible to reach 120. Increased to 2.5mg my resting rate was average 28 and the most it would reach was 70.

[kenkeith]

Hi tonitee.  Thanks for your question. I have been on a beta blocker for 6 years, and I had the same question.  My doctor is a non-interventional cardiologist and considers exercise as an important component for heart healh.

After the effective dosage and brand has been evaluated by your doctor, you can find your target heart rate by the amount that your resting heart rate has been lowered by the beta blocker. For example, if your resting heart rate has decreased from 70 to 50, then try working at a target heart rate 20 beats per minute lower than what you used to do. This way of calculating your adjusted target heart rate isn't precise, and sometimes the peak exercise heart rate is affected much more than is the resting heart rate.

An exercise stress test is the best way to establish a new target heart rate on beta blockers, and the target was measured in METs.  It uses the Bruce Protocol and meaasurement is in METs (metabolism equivalent test) burned correlated with vital signs.  The number of METs can be crossed referr3nced  to other aerobic activities such as bicycle, cross country workout, swimming, etc.