CIENCIASMEDICASNEWS: How do beta blocker drugs affect exercise?

domingo, 31 de marzo de 2013

How do beta blocker drugs affect exercise?

Beta blockers are a type of cardiac medication prescribed after a heart attack or to treat abnormal heart rhythms (arrhythmias) and other conditions. They slow down your heartbeat, and that raises a common question about them: Do they affect your ability to exercise?

The answer can vary a great deal, depending on the severity of your condition, so checking with your healthcare provider is vital. It’s also important to understand how these drugs affect your heart.

Beta Blocker Basics
Beta blockers relieve stress on your heart by slowing the heartbeat. This decreases the force with which the heart muscle contracts and reduces blood vessel contraction in the heart, brain and throughout the body. They are prescribed under several common brand names, including Propranolol (Inderal), Metoprolol (Lopressor), Atenolol (Tenormin) Acebutolol (Sectral), Bisoprolol (Zebeta) and Nadolol (Corgard).

Beta blockers may be used to treat abnormal heart rhythms and to prevent abnormally fast heart rates called tachycardia, or irregular rhythms like atrial fibrillation. Since they reduce the demand of the heart muscle for oxygen, they may be useful in treating angina, or chest pain, which occurs when the oxygen demand of the heart exceeds the supply. Beta blockers improve survival after a heart attack and also are used to treat high blood pressure and other heart conditions.

Beta Blockers and Physical ActivityInterestingly, beta blockers and exercise have some similar effects on your body.

“Your blood pressure and heart rate are similarly changed by exercise and beta blockers,” said Gerald Fletcher, M.D., a cardiology professor at the Mayo Clinic in Florida. “When you become exercise-trained your heart slows and your blood pressure lowers.”

Of course, that doesn’t mean you can take beta blockers in lieu of exercise. Exercise has many other benefits and is important to maintain your health. Read how physical activity improves the quality of life.

Concerns About Exercising While on Beta Blockers“It’s important to remember that your heart rate is being slowed, and to adjust accordingly if before you took these drugs you monitored your exercise using heart rate,” said Dr. Fletcher, who is also a volunteer with the American Heart Association.

“Don’t overdo it trying to get your heart rate up to previous levels,” he said.

There are a couple of ways to monitor your exercise intensity.

If you have been using a target heart rate to get to the right intensity, Dr. Fletcher recommends a brief exercise stress test with your healthcare provider to determine your new target heart rate. This test is important because beta blockers affect everyone differently, so there is no other way accurate way to calculate your target rate without it.
The second way to monitor your intensity is simpler: making sure you’re not too exhausted.

“Exercise hard – to the point of being tired – but not excessively hard,” Dr. Fletcher said. “If you reach a point where it is hard to talk, that is probably too much.”

I’m still worried, what do I do?It is important to know you are taking these medications for a specific reason. But if you are still concerned, talk to your healthcare provider. He or she may prescribe a newer beta blocker or another medication that has less of an effect on heart rate.

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