Beta Blockers

Hi Docs. I’m 65, had an MI and a stent a few years ago. No residual damage, but my cardiologist has prescribed a 2.5mg each day of metoprolol. If I understand the mechanism correctly, among other things this puts a kind of “cap” on my heart rate. Never seems to go above 132, even while intensively exercising (like a HIIT workout) my heart rate can only go so high. I can’t quite sort out the implications of this. Will this limit my capacity to exercise or improve my cardiovascular fitness? Any other exercise related effects? I would appreciate hearing your thoughts.

I have not noticed any effects while lifting.

Thank you.

Michael

Yes, metoprolol limits heart rate increases and it would limit top-end aerobic exercise capacity.

There are some patients in whom it may be reasonable to taper off the beta blocker (particularly beyond 3 years post-MI), whereas there are others in whom it would be strongly recommended to stay on the medicine for life (for example, individuals with heart failure or angina). This may be worth discussing with your cardiologist to see which category you fall in.

Thank you for that reply. What I can’t quite figure out is whether this is a problematic process. Does it mean my days as a CrossFit competitor (jk) are over, because it can’t do the intensity. More seriously, I noticed taking brisk walk up a relatively steep hill was harder than I thought it should be, or even the HIIT I find I can’t do them as “intensely.” What I’m not clear about is whether this will improve with additional training, or if this is the result of the medication putting a limit on my cardiovascular capacity. In other words, a feature, rather than a bug.

You can still generate some adaptations, but yes, the medication is also putting an upper limit on your capacity. There are also some other effects that can be beneficial in certain cardiac contexts (specifically heart failure), but I don’t get the sense that this applies to you.