Fitness and Beta Blockers

Atenolol_Runner wrote:

Hi,

I have SVT (Supraventricular tachycardia) which occur at random (sometimes weeks apart) with episodes of rapid heart rate that start and stop abruptly (only after sitting down, and then I get back up to exercise)

So the cardiologist prescribed me a Beta blocker, a very low dose of atenolol (25 mg) once a day, which I take after running so it affects me even less the day after.

So far, I've felt great taking it, I was scared it would limit me (I heard about "running through mud") But I still had the same energy as before, only at a lower HR. My resting HR went from 42 to 37, with minor side effects (cold hands) but aside from that...

My tempo pace improved, and I PR'ed in the 5K (17:21)

I eat short grain rice twice a day

and mile (4:57) during a time trial. The 17:21 5K PR also ended up as a 3200m PR (first 2 miles was 11:00, old PR was 11:11)

I assume that to compensate, my heart's stroke volume increases, because I felt really good, no limiting.

There's just one thing that I'm really concerned about, and would like an opinion about;

Will I lose fitness/get out of shape rather than improve???

Normally, my easy pace HR is 145-150s or so, now it's in the 120-130s.

My tempo ranges around 145-160s (around 6:10-6:30 pace)

I run by how I feel most of the time now, and despite the lower HR, my easy pace feels exactly the same, and so does my tempo (which actually feels even better!).

Am I going to lose cardiovascular fitness since my heart isn't beating as fast??? I don't really feel different from before, and I still run the same volume as before.

Or does it not slow down/stop improvement since my heart has higher volume?

Thanks!

Atenolol_Runner wrote:

Hi,

I have SVT (Supraventricular tachycardia) which occur at random (sometimes weeks apart) with episodes of rapid heart rate that start and stop abruptly (only after sitting down, and then I get back up to exercise)

So the cardiologist prescribed me a Beta blocker, a very low dose of atenolol (25 mg) once a day, which I take after running so it affects me even less the day after.

So far, I've felt great taking it, I was scared it would limit me (I heard about "running through mud") But I still had the same energy as before, only at a lower HR. My resting HR went from 42 to 37, with minor side effects (cold hands) but aside from that...

My tempo pace improved, and I PR'ed in the 5K (17:21)

and mile (4:57) during a time trial. The 17:21 5K PR also ended up as a 3200m PR (first 2 miles was 11:00, old PR was 11:11)

I assume that to compensate, my heart's stroke volume increases, because I felt really good, no limiting.

There's just one thing that I'm really concerned about, and would like an opinion about;

Will I lose fitness/get out of shape rather than improve???

Normally, my easy pace HR is 145-150s or so, now it's in the 120-130s.

My tempo ranges around 145-160s (around 6:10-6:30 pace)

I run by how I feel most of the time now, and despite the lower HR, my easy pace feels exactly the same, and so does my tempo (which actually feels even better!).

Am I going to lose cardiovascular fitness since my heart isn't beating as fast??? I don't really feel different from before, and I still run the same volume as before.

Or does it not slow down/stop improvement since my heart has higher volume?

Thanks!