# Beta blockers and endurance.



## blackjack (Apr 20, 2005)

Hi.

I've just been prescribed a beta blocker (atenolol - 25mg per day) for etopic heart beats and infrequent AF.

While my heart has stopped dancing the tango, my heart rate is about 20-30 bpm lower around my local loop.

I actually feel pretty good on the bike, but haven't riden for more than an hour and a half since getting crook.

I ride for fun and enjoyment, but do a couple of 12/24 hour races solo (purely at a social pace, with plenty of break time) each year. It's all about the fun factor for me.

Can anyone give me a heads up as to how this medication will effect my endurance during a longer event.

I'm stoked just to still be able to ride.

Thanks in advance.
Cheers.


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## ThrashNY (May 18, 2005)

Do a WebMD search of the medication. That will tell you all you need to know. 

From my understanding, beta blockers to decrease endurance to some capacity though.


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## RosedaleReaper (Feb 20, 2008)

what was your maximum HR before going on the med? beta blockers can decrease the force of contractility, but how that will or may effect your performance is unknown, and possibly none. see how high you can get your HR now. some beta blockers are more specific for certain subtypes of beta receptors (B1, B2), meaning, HR vs contractility. dont waste your time on webMD, ask your cardiologist and tell him of your concerns; he does know that you ride, correct? he is the best source of information.


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## wmodavis (Jun 21, 2007)

Beta blocker drugs now considered public health hazard - Read here

and

Beta Blockers Used in Heart Surgery Increase Death Rate by One-Third - Read here


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## EpicProportions (Jul 8, 2008)

wmodavis, stick to your day job. 

Paraphrasing information that comes from a paraphrased source does not help anyone.

Beta-blockers have a role in the treatment of many cardiovascular disorders. In fact, they are essential in rate control treatment of AF (that is atrial fibrillation for the uninitiated). The risk of stroke is actually HIGHER from untreated AF than from taking the beta-blocker.

All drugs have side effects and contraindications to use. What works for some, may not for others. When you get your MD degree, perhaps you will be able to contribute useful medical comments.


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## wmodavis (Jun 21, 2007)

Dear Epic
I appologize if providing links to opposing views offends you. You're not alone. I assure you many do not appreciate the freedom we have to consider all sides pro and con on a specific topic and then make up our own mind based on our review of the information. Some minds take the easy way out and prefer to remain comfortable in their views without even reading what the other side (most issues have more than one side) says and considering if maybe there are some valid points. Some prefer ad hominem attacks to even speaking to the issues raised in opposing views.

I'm sure you will also be offended by the following quote from the BMJ (http://www.bmj.com/cgi/content/full/334/7600/946?grp=1) that is if you can even understand it.

"Two large meta-analyses also question the value of blockers in cardiovascular protection of hypertensive patients.2 3 These show that atenolol is inferior in reducing stroke and mortality, but non-atenolol blockers may be equivalent to other antihypertensive drugs.

Carlberg reviewed the effects of atenolol on cardiovascular outcomes in hypertensive patients aged 52-70 who were followed up for 4.6 years. In four studies comparing atenolol with placebo (6825 patients) there was no difference in total mortality (relative risk 1.01, 0.89 to 1.15), cardiovascular mortality (0.99, 0.83 to 1.18), myocardial infarction (0.99, 0.83 to 1.19), and stroke (0.85, 0.72 to 1.01). In five studies comparing atenolol with other antihypertensive agents (17 671 patients), despite equivalent reduction in blood pressure, atenolol treatment was associated with higher total mortality (1.13, 1.02 to 1.25), cardiovascular mortality (1.16, 1.00 to 1.34), and stroke (1.30, 1.12 to 1.50).

Lindholm's meta-analysis was more comprehensive, reviewing 13 trials (105 951 patients) comparing blockers with other antihypertensives and seven trials (27 433 patients) comparing blockers with placebo. Overall, blockers were inferior to other antihypertensives in preventing stroke (1.16, 1.04 to 1.30), but the results were different for atenolol and non-atenolol blockers (table 1). Compared with other antihypertensive drugs, atenonol was associated with higher risk of stroke (1.26, 1.15 to 1.38) and total mortality (1.08, 1.02 to 1.14). Non-atenolol blockers were not inferior to other antihypertensives in preventing stroke (1.20, 0.30 to 4.71), myocardial infarction (0.86, 0.67 to 1.11), and total mortality (0.89, 0.70 to 1.12). "


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## EpicProportions (Jul 8, 2008)

wmodavis, no offense taken. My only comment was to suggest you are comparing "apples to oranges".

The OP was describing a different medical condition. Not hypertension! The articles you so determinedly shove down our throats refer to hypertension. There is no question that there are other more efficacious drugs to treat HTN. That wasn't my issue. 

If you referenced articles related to the original question I would be more content. I would suggest you create a new thread, rather than to introduce fear mongering to a totally different issue.

Keep up the reading!:thumbsup:


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## frank (Jan 10, 2004)

Different people get different result. I have taken one for 15 years because of AF and hypertension and the dose if higher than 25mg. I do not beleive the drug causes me any lose of endurence but it is hard to tell. What I can say is that my heart rate will not go over 140, so I am stuck with a top end limit. I know several other people who ride and take beta blockers, one has a top end of about 125 and that's it. I have read that antenol is the worst of the bunch with limiting athletic performance; someone with medical experience could add more to the discussion. 
Their was an article written by a doctor on the Velonews website a few years ago that was very informative and pertained directly to cycling. I will see if I can find the link.


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## emtnate (Feb 9, 2008)

Blackjack, have you had any luck with your question from the doc? How is the riding going? My experience with long term experience with beta-blockers is purely textbook, our uses in EMS differ. Like Frank said, beta-blockers will reduce the upper limit of your heart rate and contractile force. This means when you're working hard and the various body systems are demanding more oxygen, there is a limit to how fast the heart can deliver O2, and also how fast the heart can get more 02 in return for working harder. You can see how this would effect your endurance in the long run. 

That being said, your cardiologist can advise the best course of action. Different drugs work in different ways. Atenolol might be the best choice for you, or there might be a better drug. In any case, I'd always get as many opinions as is practical. At the very least, I'd ask the same questions you asked here to your cardiologist, family doctor, and pharmacist, if you haven't already.


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## lonestar350r8 (Aug 13, 2007)

Hi blackjack, to give you the short and sweet of your question yes it will decrease your heart rate. During long races such as the 12-24hr of riding your muscles will have decreased blood flow and oxygenation. With that in mind your muscles will begin to go into and anerobic state to get energy. So the potential for lactic acid build up can be expected along with cramps and muscle pain. You are already at target dose for atenolol and as long as you maintain a more regular heart beat you should be fine. Just remember not to push your self to exhaustion because it will be more difficult to recover. Unfortunatly your problem can not be regulated without effects on your performance.


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