Beta blockers and sport - how do they get along?


Beta-blockers are a group of drugs that are used primarily to treat arterial hypertension (high blood pressure) or cardiac arrhythmias.
This makes use of the fact that receptors, which are inter alia are on the heart muscle are blocked by a beta blocker and so i.a. Adrenaline cannot reach you to work. Adrenaline is a substance that increases blood pressure and increases the heart rate. In addition to the blood pressure lowering and heart rate lowering effects, beta blockers also have a number of side effects that must be considered. These include tiredness and exhaustion, possible impotence or shortness of breath (adrenaline leads to bronchial dilatation via beta receptors on the lungs. A blockage of these acts in the opposite direction = bronchial tubes contract = shortness of breath).

Can I exercise while taking beta blockers?

The practice of sport and especially endurance sports help to lower blood pressure in general. Endurance athletes who train their condition regularly have a larger heart muscle than non-athletes. The larger the heart muscle, the slower it has to beat per minute in order to transport the required blood volume per minute through the body (relief of the heart muscle in athletes).

Physiologically, this mechanism becomes noticeable in that the heart rate drops. While the heart rate for non-athletes should be around 80 beats per minute, it can also happen that trained competitive athletes have a heart rate of around 50-60. The blood pressure of well trained athletes should be around 120: 80 mmHg. In the absence of kidney disease, athletes who exercise regularly do not usually have high blood pressure. As a rule, it is non-athletes and / or overweight people who are prone to this clinical picture. In the case of cardiac arrhythmias it looks a little different, since athletes can also suffer from irregularities in the transmission of stimuli in the heart muscle. The reason for this is often the heart muscle that has become too large due to intense exercise.

If the heart muscle is too large, the corresponding conduction pathway increases with the muscle, which can lead to corresponding arrhythmias. If a beta-blocker is discontinued for a high blood pressure patient, the question often arises whether it is possible to exercise under this medication. In principle, it can be said that it is possible to do sports with beta-blocker therapy. However, a few things should be considered here.

Possible symptoms with ingestion and physical activity

The ingested beta blocker lowers blood pressure and heart rate. While heart rate increases slightly during exercise, blood pressure may decrease after a brief increase. The heart rate lowered by a beta blocker does not rise as much as in patients without a beta blocker.
However, the blood pressure, which is also reduced under a beta blocker, can be further reduced through exercise after a brief increase.

Any patient taking a beta blocker should pay close attention to any new symptoms while exercising. If dizziness, shortness of breath or pressure on the chest occurs, activity should be stopped immediately. In this case it may be that the necessary increase in heart rate, which would be necessary to provide enough blood for the body cells during sporting activity, is not sufficient. The body then enters into an oxygen debt, which would make itself felt with shortness of breath, exhaustion or pressure on the chest.
Dizziness could also be a sign that the heart rate increase required, which is not achieved with a beta blocker, is not sufficient to maintain the metabolic processes necessary in the body. The additional lowering of blood pressure carried out by a beta blocker can also mean that the blood supply in the body is simply insufficient during physical activity and leads to symptoms.
If you start again with a beta-blocker, a 24-hour long-term ECG can be used to see whether there are significant reductions in frequency under a beta-blocker. In this case, you should definitely reduce the beta-blocker in order to avoid impending undersupply of the organism and the heart.

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Stress test

If patients have high blood pressure or an arrhythmia, if a beta blocker is used, they should also do an exercise ECG when they plan to take up physical activity.
Usually on a bicycle the patient has to pedal until a certain load is reached. At the same time, the heart currents are recorded by an EKG and the blood pressure is measured at regular intervals. Here you can see whether the beta-blocker increases the heart rate necessary for sport or whether the blood pressure is not lowered too much so that not enough oxygen-rich blood can circulate in the body. As a rule, if you plan to start exercising, you should first wait with the stress test until the beta blocker has been taken for about 1-2 weeks, as it only takes effect from this point on. It should be noted that it is in principle possible to do sports while taking beta-blockers. In the event of complaints, however, either physical activity or the dosage of the beta blocker should be reduced.

What influence do beta blockers have on heart rate?

Beta blockers, which are taken regularly by many patients as so-called antihypertensive agents or colloquially as "blood pressure tablets", unfold their effect by blocking the stress hormones adrenaline and noradrenaline. They prevent these hormones from docking with their target receptor and developing their stimulating effect. As a result, the effect of beta blockers is pretty much the opposite of the effect of said stress hormones.

While adrenaline and norepinephrine raise blood pressure, beta blockers lower it. The heart rate - measurable as a pulse rate - normally increases with stress and excitement. If you block this increase with beta blockers, the heart rate drops. This is why so-called bradycardia, i.e. the excessive drop in the pulse, is one of the most important undesirable effects of beta blockers.
The definition speaks of bradycardia from a heart rate of <50 beats / min. However, depending on the initial value of the individual patient, unpleasant side effects can also become noticeable earlier. Due to the additional drop in heart rate caused by taking a beta blocker, they should never be prescribed to patients in whom bradycardia - for whatever reason - is already known.

Read more about this under: Effect of beta blockers

What influence do beta blockers have on performance?

Basically, the drop in blood pressure and pulse, which is usually desired when taking beta blockers, leads to a weakening of the subjective performance. However, if blood pressure (and pulse) were very high before the start of therapy, this weakening can be just right and bring the desired effect. Quite a few patients, however, complain of listlessness, fatigue and dizziness, especially at the beginning of drug therapy with beta blockers.

The other extreme occurs in very nervous, excited or even anxious patients: Beta blockers have a calming effect on this group of people by lowering blood pressure and heart rate and reducing the stress level, which can potentially increase performance. Since excessive nervousness is buffered, there are fewer careless mistakes caused by excitement and the ability to concentrate increases. For this reason, beta blockers are used in addition to the therapy of high blood pressure in patients with severe stage fright, extraordinary test anxiety or panic attacks.

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Beta blockers as doping agents in sports

Of course, the desired or unwanted effects of beta blockers can be used as a method of doping, even in sport.
Especially in sports that require great accuracy and full concentration, beta blockers clearly increase performance. Taking beta blockers can reduce tension and nervousness before competitions, which corresponds to an unfair competitive advantage. For these reasons, the national and international associations for archery, golf and skiing have placed beta blockers on the list of substances prohibited in sport.

In other sports, on the other hand, especially in endurance-oriented competitions, taking a beta blocker is not counted as doping and is therefore not controlled. In sports that require less skill but greater endurance and / or strength, taking a beta blocker even has a weakening effect on the athlete's performance, so that a doping attempt is unnecessary.

Read more about this under: Doping in sport