Adjusting to beta blockers

I am a 45 yr. old female recently put on beta blockers due to pvc's/pac's.  I totally understand that this lowers my heart rate in order to regulate it.  For 20+ yrs. I have worked out intensely and kept track of my 'target' heart rate and calorie burn with a heart rate monitor.  Since being on the beta blocker I can no longer reach my target hr for my age (122 - 139) and this is very frustrating.  I'm also burning around 40% fewer calories.  My question is, am I still receiving the same benefits from my exercise and is there a way to figure out what my 'new' target heart rate is now that I'm on the beta blocker?  Also, is weight gain inevitable unless I restrict my intake?  I've already gained a few pounds.  I'm assuming the med. also slows metabolism in general?  And finally, I was already switched from atenolol to metoprolol because of problems with severe constipation and gas with atenolol.  I'm beginnng to experience these same difficulties with the metoprolol as well.  Is this also something that is inevitable with beta blockers?  It's not something I'm sure I can tolerate on a long term basis, yet I don't like the idea of the regular use of laxatives either. I realize this is quite a lot of info I am seeking but this is all new to me.  Any advice you can offer would be greatly appreciated.  

[bypeep]

I'm not sure, but I can vouch that there is some correlation to constipation and gas because I had my Nadolol upped from 40mg to 60mg per day in November and by Christmas I was doing acrobatics on the toilet just to get a bb-sized pellet out. By mid-January I was so fatigued that I thought I was going to die. I cut back to 40mg and amazingly enough, I actually feel the rumblings of peristaltic motion once again. My energy is slowly returning too. I believe it has something to do with either metabolism or it's affects on the smooth muscles. I go back to my EP on 2/18 and plan to ask him what it could possibly be.

[Jerry_NJ]

I'm a male, don't know if gender has anything to do with side effects, I think much is the same.  

I have taken up to 200 mg of Metoprolol a day and the only side effects I had that were troublesome was a very low BP and some dizziness.  This subsided over a couple of weeks at that level, but I have subsequently been changed to 50 mg of slow release coupled with 240 mg of Calcium Channel Blocker.

I no longer run on the treadmill, but I can say when BB was able to hold me in NSR I was able to run my HR up, I had to slow down to keep it under 150, and as I was in my early 60s then that was a bit too high.  What I am saying is while the BB slowed my HR down, my HR still went up with physical load, and when I was running at my desired speed of 6 miles an hour I couldn't hold it for more than a few minutes without going over 150 for HR.  I had to slow down, tread mostly on the level, 5.5 mph or there about.  As the years pass I find the BB doesn't lower my BP any more, or I now suffer from high BP and the BB is bringing it down to an acceptable level.  That is, my BP is just acceptable at around 120/80, ofter a bit lower on both numbers. Conclusion? One's body adjusts to medications.  In my case I think it is still keeping my HR low enough to be acceptable, below 90 ar rest.  I am no longer in NSR, full time AFib for me.

[tom_h]

I too have taken up to 200 mg of Metoprolol, but it wasn't for long.  My BP and heart rate was so low, that it felt like a block of concrete was on my chest if I did any physical exertion.  I dropped back to 100mg, and that was better.  Now I'm on 50mg, and still get what we're looking for with only minimal side effects. I find that my heart doesn't respond to demands as quickly as it did without it.  I have to warm up first to get it up to speed.  I was also forced to stop actively competing in my chosen sport as I was no longer able to perform at a level necessary to acheive my personal goals.  That didn't stop me, but I now do it for fun and exercise.  Besides, at 60, competing at an elite level is many years in the rear view mirror.  At this age, they give you the moniker of "Grand Master", which is a nice way of saying, "Really Old Guy".

Weight gain?  You bet!  At one point I was 40lbs over my pre-BB weight.  This also attributed less than stellar performance.  I've now parred that back to 25 lbs. over my former competitive weight.  Now I'm 60 years old, and my metabolism I'm sure is lower than yours at your age. But expect "body changes" once you get on BB.

Remember the lower heart rate is merely a side effect of the drug, not its primary function.  Also, I found that for me, Metoprolol did squat for my PVC's; nothing.  It did make conversion of my SVT's a heck of a lot easier.  I had a persistent type of SVT.  It would not drop out by itself, but run on until it was converted by an outside function, in my case Valsalva.  Metoprolol helped greatly in making it easier to convert.

Also, there are 2 types of Metoprolol,  Metoprolol Tartrate, and Metoprolol Succinate.  The latter is a time release version called Toprol XL.  This is nice because you only need to take 1 tablet a day.  The downside is it's a high tier drug for insurance companies its price is really up there.  I get a Metoprolol Tartrate for about 25% of the price.

I found the drug easy to tolerate, and experience limited side effects.  I was particularly concerned about its effect on libido, but I can't say it has affected that at all! 8-)