Low blood pressure a cause of poor exercise capacity?

[runnertom]

I am a 58 year old male who has been an avid runner and cyclist for 30+ years. I had CABG 3 1/2 years ago to bypass a clogged LAD. Since then all has been well with my normal exercise regimen but last year I was diagnosed with LVH with a left ventricle wall and septum of 1.5 cm (presumably due to exercise induced hypertension as my normal BP was quite normal).  Serial echos since surgery showed the wall thickness progressing from high normal of 1 cm to the current level. Doc put me on 5 mg of lisinipril as it has been shown to cause regression of LVH. More recently, I have had a number of bouts of atrial fib that converted after about 24 hours without intervention. Doc added 25 mg Torpol XL to suppress these. This has not been totally effective as I have had an episode while on the Toprol.
I am now experiencing resting BP averaging 100/60 and often lower. When I first started taking the Toprol, I didn't notice any effect on my exercise but I now feel like I am wearing a governor. I don't have any trouble achieving heart rates above 160, but my legs feel like lead. Could the low BP itself be the cause or should I look elsewhere? If this is likely to be a class effect of the low dose beta blocker, could you suggest another therapy for my problem?

[CCF-M.D.-MJM]

Hi Tom,

Could the low BP itself be the cause or should I look elsewhere?

Unfortunately it is probably the beta blocker.  Beta blockers are known to make people feel sluggish, especially during exercise.  Beta blockers do not decrease your risk of atrial fibrillation -- at least there is not data to show that beta blockers decrease your risk of AF.  It will however decrease your heart rate while you are in atrial fib.  You could try just taking the beta blocker if / when you have AF.  As usual, ask your doctor before you change your medications.

If this is likely to be a class effect of the low dose beta blocker, could you suggest another therapy for my problem?

I would take the beta blocker as needed for heart rate control with atrail fib.  If you want to try to stay out of atrial fib, that is a different situation.  Tikosyn is probably the best solution for the short term.  If tikosyn is successful, that is great.  If not, ablation is another option.  Sotalol has beta blocking effects and amiodarone is probably not a good long term solution to atrial fibrillation.

I hope this helps and keep up the exercise.

[dafan]

As a fellow runner and 51 yrs old I am encountering the same difficulties. Im on 25g of Toprol XL also. I was Rx them for suppression of PVC which for the most part has been successful. I have been a pretty heavy exerciser for years. My blood pressure was running in the range of 145/90 and with the addition of Toprol it goes from about 110 over 70 to 115/75. Ill be interested in the answer. However from the beginning i noticed a "heavy leg" effect. Good luck!

[Mantels]

I have also had the same issues. I am an avid triathlete and I recently went down to 25 mg Toprol from 50 mg (MI 12/2003, stents LAD 100% blockage, medicated stent 5 months ago after another total blockage in same place).

My weight has dropped a little, which I expected. The heavy legs is from I suspect over training or not enough stretching.

I have incorporated a power yoga regime on my 2 days a week off and have eliminated the "dead" feelings in my legs.

I still have the energy to train hard (HR 155-165) 5-6 days a week.

Just a thought.

[NurseKagome]

I just wanted to say that your bp is perfect!!! 115/75 is an awesome reading, be happy for that. though the "ideal" bp is 120/80 there is research being done now claiming that a bp below 115/75 is the best for longivity and decreased arterial damage later in life! haha. well hope this helps a little.

the nurse was here :)

[dafan]

Thanks!!! Glad to know that! Perhaps my body was conditioned to the higher bp, also my resting pulse rate has always been very low... 44-48 at rest. Now at complete rest sometimes it is 38 to 40. Also failed to mention that legs dont really feel heavy anymore but seems to take a little longer to "get going" Thanks for the comment*S*

[Prof. ATP]

Tom,

I took Toprol for a while to suppress some mild arrythmias following my CABG in 1998.  It made me miserable; like you say, I felt like I was on a governor.  As soon as I stopped it (which is a little tricky), the governor went away.

I have a triathlete friend who has chronic AFib, but I don't think he takes anything for it.  I had one bout, after my stent in October, but it converted spontaneously and has stayed sinus ever since.

A physician whom I respect tremendously thinks that any ideas I have about going faster are "silly and unrealistic".  This comment was based solely on my age (51).  He knows that I have good pulmonary and cardiac function and few mechanical problems.

My resting BP tends to be low (typically 105/70), but during exercise it rises in a normal way; it seems to me that the only way to test your hypothesis is to take BP readings while exercising.

Good luck; I am off to the pool!

[runnertom]

Prof
Thanks for your comments. I would like to take my BP during exercise but am having a difficult time of it. My automatic cuff gets confused and I haven't found anyone willing to run with me while doing it. I am considering elisting the aid of one of my RN sisters by having them ride on the rear of my tandem bike to take the reading. A treadmill is the obvious choice that I don't have easy access to.
   I have found today by wearing my pulse monitor while riding that my pulse is perhaps 15 bpm slower for a given workload than without the beta blocker. Previously, riding 20 mph on flat ground resulted in a pulse of 140. Now, its about 115. I don't understand how my muscles get enough blood to work at the lower heart rate if the beta blocker also reduces stroke volume. No wonder they don't feel good!

[pbanders]

It's the beta blocker. I'm taking 75 mg of metoprolol daily, I was a bike racer for years. I live in Phoenix, it was 113 degrees, my BP gets down to as low as 75/50 after a long ride in the heat.

Ever since going on metoprolol, my legs have been like lead, my training response sucks, and when I go to altitude, it's like I've never been on a bike before. But, if I look at my training performance, it's not really so bad, my real performance is only down about 10% or so. You just have to work through the fatigue. I do 5X per week, about 10 hours, around 175 miles.

[runnertom]

I guess my focus from here on will be in living with the effects of the Toprol. As the doctor said, beta blockers really have not been shown to have any effect on atrial fib. In fact, I have had a bout since being on the Toprol. I think anxiety an caffeine are larger factors for me and I will do my best to control them.

I don't know what the root cause of my Afib is, but I think its quite possible the long endurance exercise history might be a factor. I know three other bike racer/runners who have Afib problems. One is my younger brother whose exercise history parallels mine. His was successfully ablated at Cleveland Clinic a few years ago. His was brought on by exercise and resulted in very high ventricular rates. Mine differs in that in two cases I converted back to sinus during a bike ride.

I guess the hassle with the beta blocker is worth the effort. Something related to high blood pressure must have been responsible for my LVH (and maybe my original LAD blockage) so getting it as low as I can tolerate would seem to be a good thing.

[pbanders]

I, too, have a number of friends from cycling who have developed cardiac problems, including arrhythmia. I know three guys who have had mitral valves blow out, I had an ascending aortic aneurysm, and I know about five guys with rhythm problems. However, I still believe it's mostly anecdotal, and when I look at those I know who don't exercise, the alternatives look a lot worse to me.

I'd stick on the beta blocker and keep working with your doctor on finding one that you tolerate better. I'm going to try to get my doc to drop my dosage to 50 mg daily next time I see him, as my BP is low and well controlled.

[runnertom]

Its a fact that lone Afib is more common in endurance athletes than the general public. I have seen studies to that effect and my GP mentioned it to me the other day. I think the theory is that the stetching of some of the tissue in the area where the pulmonary veins enter the right atrium is though responsible. Whether true or not, I wouldn't see this as a reason to avoid strenuous exercise.

I also have a few anecdotal cases of LAD blockages in long time cyclists. I have theorized that the turbulence created by the high blood flow and blood pressure over hours of high level exercise could be responisble. I have not had much buy-in for this theory. I was told by my surgeon however that the reason they could not stent my lesion was because it was too close to the branching (bifurcation) and the high turbulence there would cause it to clog up quickly.

In my case and I would guess in yours, people were absolutely shocked that I had cardiac problems. I had none of the classic risk factors including family history. At least my physical fitness resulted in a very fast recovery from surgery and return to my former activities.

[runnertom]

I guess one of the more troubling aspects of all this is if the cycling/running were in some way responsible for cardiac problems, it would be the last thing I should be doing now. I have had absolutelely no support for this line of thinking from anyone in the medical community. Everyone says "keep doing what you were doing" although some have cautioned that racing may not be a good idea.

[dquenzer]

I had lone afib for about three years.  I am also on beta blockers (more preventative than anything) and they clearly affect exercise performance.  I find that the first quarter mile is the worst.  It seems like it takes awhile to get warmed up.  But I clearly can't run as fast and as long.

But I'm 51 and really don't care.  My racing days are over, and I really think that overdoing it isn't all that good as you get older.  Too many knee and joint problems can develop.  No proof that exercising beyond moderate levels has any longevity affects.  Everything in moderation.

Also I would suggest an ablation.  I had a pulmonary vein ablation and it took care of the AFIB.  Tikosyn didn't work.   Drugs generally only last for awhile and then stop working.  

Make sure you have good insurance!  I went to Mayo and it was 55,000.  Thankfully my insurance covered most of it.  Been AFIB free for 3 years.

[nancy1948]

A related discussion, blood pressure lowers during jogging was started.