Beta Blockers: What They Are, What They Do & Side Effects

When you’re in a stressful or tense situation, your body has a natural fight-or-flight response that causes your heart to beat faster than normal. Beta blockers are a class of medications that prevent the stress hormones that contribute to your body’s fight-or-flight response from affecting your heart.

Most beta blockers are designed to treat heart conditions, such as high blood pressure, an irregular heartbeat or a high risk of heart attack. They’re also used to treat anxiety disorders, hyperthyroidism, tremors and diseases like glaucoma.

Below, we’ve explained what beta blockers are in more detail, as well as what they do to your body when you use them. We’ve also explained how beta blockers can be useful for treating anxiety and calming your nerves in tough, stressful situations.

What Are Beta Blockers?

Also known as beta-adrenergic blocking agents, beta blockers are medications that block the effects of adrenaline, or epinephrine, on your heart, as well as other stress hormones such as noradrenaline.

Adrenaline and noradrenaline are used by your body to activate your fight-or-flight mechanism, which is designed to protect you in a dangerous situation.

Normally, being in a stressful situation causes your body to secrete more adrenaline, resulting in a noticeably faster heartbeat. You might also notice your hands becoming shaky and sweaty, as well as your voice becoming shaky and faint.

Many people also experience dizziness—another physical effect of an increase in your body’s adrenaline levels. This increase in adrenaline and its noticeable effects can cause you to panic when under pressure.

Beta blockers reduce the effects of adrenaline on your heart, making it easier for your heart to relax in the presence of stress hormones. Instead of a fast heartbeat, your heart will beat at a normal pace, limiting the physical effects of adrenaline on your body.

There are numerous beta blocker medications available. Most beta blockers target the heart specifically, while others also reduce your body’s secretion of angiotensin, a hormone that can restrict your blood vessels.

What Do Beta Blockers Do?

Beta blockers are used to treat several different conditions. Most beta blockers were designed to treat heart conditions such as high blood pressure and irregular heartbeat (atrial fibrillation), both of which can contribute to excessive stress on the heart.

By reducing the amount of stress on the heart muscles, beta blockers can make heart attacks and other major health issues less likely.

Many doctors also prescribe beta blockers for anxiety. By blocking the effects of stress hormones like adrenaline on your heart, beta blockers can block the physical effects of anxiety on your body, such as sweating, a rapid heartbeat or dizziness.

When using beta blockers for anxiety, It’s important to understand they don’t treat the psychological causes of anxiety itself. Instead, they just make it easier for you to handle the physical reaction your body might have to feelings of anxiety.

Some beta blockers are also used to treat hyperthyroidism, which can contribute to excessive weight loss, tremors, sleep issues, nervousness and other symptoms.

Beyond treating heart conditions and reducing the physical effects of anxiety, beta blockers may also have other health benefits. For example, some beta blockers are linked to reduced levels of bone mineral loss in people at high risk for osteoporosis and bone resorption.

Beta blockers have been in use since the 1960s, but today, there are several beta blockers on the market, many of which are actively used as treatments for heart and anxiety conditions. Some of the most widely used beta blockers include:

  • Acebutolol
  • Atenolol
  • Bisoprolol
  • Carteolol
  • Esmolol
  • Metoprolol
  • Nadolol
  • Nebivolol
  • Propranolol

What Are Beta Blockers Side Effects?

Like almost all medications, beta blockers can have side effects. Most of the beta blockers side effects of beta blockers are fairly mild. It’s also possible for beta blockers to interact with other medications and cause more severe, serious side effects.

The vast majority of people who use beta blockers do not experience side effects. Overall, beta blockers are safe and very effective, with a low risk of side effects when used according to your doctor’s instructions.

The most common side effects of beta blockers are:

  • Fatigue. Because beta blockers cause your heart rate to decrease, it’s common to feel a slight reduction in energy. Some people who use beta blockers feel fatigued after starting treatment due to the effects of the medication on the heart.

    If you feel fatigued after using a beta blocker, it’s best to talk to your doctor. Most of the time, this side effect can be avoided by adjusting your dosage or using a different type of beta blocker medication.

  • Weight gain. Some beta blockers, particularly older medications such as metoprolol and atenolol, can contribute to weight gain. While there’s no consensus on why this happens, it’s believed to be linked to fluid retention or the medication’s effects on your metabolism.

    Most of the time, weight gain from beta blockers is fairly mild. Expect to gain one or two pounds, if anything. This weight gain can often be reversed by switching to a newer beta blocker.
  • Cold feet and hands. Beta blockers can potentially make your hands and feet feel cold as a result of their impact on your blood circulation. Like many other side effects of beta blockers, this can often be avoided by adjusting your dosage or changing medications.
  • Nausea, dizziness and lightheadedness. It’s fairly common to feel slightly dizzy and lightheaded after using beta blockers, especially the first few times. This side effect is usually temporary and tends to disappear after using beta blockers for several days.

There are also several less common side effects of beta blockers. These include:

  • Slow heartbeat. Beta blockers are designed to relieve cardiovascular stress by giving you a slower heartbeat. If you take too large a dose of your beta blocker medication, it’s possible to experience bradycardia, or an unusually slow heart beat.

    If your resting heart rate while awake is under 50 beats per minute after you take a beta blocker, contact your doctor. This side effect is most common if you use calcium channel blockers at the same time as beta blockers to treat hypertension.
  • Higher cholesterol and triglyceride levels. Some beta blockers can cause a reduction in your high-density lipoprotein (HDL, or “good cholesterol”) levels, as well as increases in triglycerides.

    This side effect is often temporary and can reverse over time. Overall, beta blockers are effective at treating heart conditions and shouldn’t be avoided because of the potential for changes in your cholesterol levels.
  • Asthma attacks. Although the science isn’t completely settled here, some beta blockers are linked to an increased risk of asthma attacks in people with severe asthma.

    This side effect is most frequently documented with older medications. It’s less common with newer beta blockers, the majority of which are safe for people with mild to moderate asthma.
  • Cramps. Although it’s uncommon, some people experience cramps—particularly in the abdominals—while using beta blockers.
  • Depression. Like asthma attacks, the science on beta blockers and depression isn’t completely settled. A small percentage of people who use beta blockers experience depression and memory loss, although this may not be caused by the medication.

Because beta blockers affect your heart rate, they can also affect your life in ways unrelated to anxiety and heart issues:

  • Interaction with stimulants. It’s recommended to avoid stimulants such as caffeine while using beta blockers, as caffeine can increase your heart rate, anxiety symptoms and blood pressure, countering the effects of beta blocker medications.
  • Effects on exercise. After taking a beta blocker, your maximum heart rate will be lower than normal. This means you might have less stamina while exercising, especially if you do cardiovascular exercises such as running, cycling, walking or rowing.
  • Consumption of high-sodium foods. Eating foods that are high in sodium, such as fast food, can raise your blood pressure and put extra pressure on your heart. If you’re prescribed a beta blocker for heart issues, it’s best to avoid eating high-sodium foods.
  • Consumption of high-potassium foods. Because beta blockers affect your body’s ability to process potassium, it’s also recommended to avoid potassium-rich foods if you’re prescribed a beta blocker for heart issues or anxiety.

Overall, beta blockers are a safe, reliable and effective medication. Most people who take beta blockers experience few or no side effects, especially with the newer medications used today.

Selective vs. Nonselective Beta Blockers

There are two main types of beta blocker medication: selective beta blockers and nonselective beta blockers.

Selective beta blockers are designed specifically to block the β1 receptors, which are primarily located in the heart. Because the action of these beta blockers is more specific, they’re usually safe for use if you have diabetes.

Common selective beta blockers include acebutolol, atenolol, bisoprolol, betaxolol, bevantolol, celiprolol, metoprolol, esmolol and nebivolol.

Because selective beta blockers only affect the β1 receptors, which are concentrated in heart tissue, they tend to be used to treat heart conditions and aren’t a popular treatment option for anxiety.

Nonselective beta blockers are designed to block the β1, β2 and β3 receptors. This means that as well as targeting beta receptors in the heart, they also affect the veins, liver, pancreas and a range of other parts of the body.

Common nonselective beta blockers include alprenolol, carteolol, oxprenolol, propranolol and sotalol. As well as being used to treat certain heart conditions, nonselective beta blockers can be used to treat some physical effects of anxiety.

Unlike selective beta blockers, nonselective beta blockers are not considered safe to use if you have diabetes.

Learn More About Beta Blockers

Beta blockers are some of the most widely used medications in the world, prescribed for heart conditions, anxiety and more. Safe, easy to use and effective, they provide fast and noticeable results that make them ideal for preventing chronic anxiety and panic attacks.

Our guide to propranolol goes into more detail on how one of the most widely used beta blocker medications works, from its history to major benefits, potential side effects, drug interactions and more.

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.