Is THC Bad for Your Heart and Blood Pressure?

Cannabis use is increasing in the U.S. and worldwide, particularly among older adults. It is becoming more widely available to people as both medical and personal cannabis use have become legal in more states. However, cannabis is still in the most dangerous category of controlled substances in the U.S., alongside drugs like heroin, LSD, and ecstasy. This makes it challenging to conduct research on its safety.

There are some known health benefits of using cannabis, as well as risks and side effects. When it comes to heart health in particular, there are risks associated with THC — the main component that gets you high.

Read on to learn about how THC affects heart health and if you might be at increased risk.

What is THC?

THC (tetrahydrocannabinol) is the psychoactive chemical in the cannabis plant. In other words, it is the chemical responsible for the “high.” The other main active part of cannabis is CBD (cannabidiol). CBD doesn’t cause a high and has shown to have some benefits for pain and anxiety.

Cannabis products contain different amounts of THC and CBD, and they can have different effects. There are some potential health benefits to cannabis (both THC and CBD), but importantly there are also known risks and side effects.

Cannabis products have varying ratios of THC and CBD and come in different forms, including:

Smoking
Vaping
Sprays
Topical creams
Edibles

How quickly the THC might be absorbed in your body depends on which formulation you use. While there is no established dose for THC, a typical dose is between 5 mg and 15 mg.

Cannabis use is growing in the U.S. and is most often used for the following symptoms:

Pain
Muscle spasms
Sleep
Appetite
Nausea and vomiting
Anxiety

Importantly, there are ris ks to THC use that you should be aware of. These include:

Altered senses
Mood changes
Difficulty concentrating
Hallucinations
Psychosis
Impaired brain development in teenagers
Breathing problems
Elevated heart rate
Nausea and vomiting

Does THC negatively affect your blood pressure and heart health?

Cannabis use, and specifically THC, can affect the heart in dangerous ways.

First, THC turns on the sympathetic nervous system. This is your “fight or flight” response. When this happens, it can:

Elevate your heart rate
Raise your blood pressure
Increase the amount of oxygen that your heart needs
Cause an irregular heart rhythm (arrhythmia) or extra heart beats
Activate platelets (important for blood clotting), which may increase risk of heart attack or stroke

Also, recent research shows an increased risk of heart attack and stroke in people who use cannabis. The risk was higher with more frequent cannabis use. This link was present regardless of the form (smoke, edibles, or vape) and whether or not people also smoked tobacco cigarettes.

Before this study, research suggested that young adults using cannabis were not at higher risk unless they also used tobacco.

Additional research has shown:

An increase in the rates of hospitalization for cardiovascular causes in young people using cannabis
Higher rates of arrhythmias (irregular heart rhythm) in hospitalized cannabis users compared with non-users

Historically, federal restrictions on doing research with cannabis has limited our understanding of its risks. But as more information emerges, the negative effects of cannabis on heart health are becoming clearer.

Who is at higher risk of heart problems from using cannabis?

You may be at increased risk from using cannabis if you:

Have heart disease
Have high blood pressure
Have an irregular heart rhythm
Are taking certain medications

THC can increase heart rate and blood pressure, which could lead to complications. This is important to consider if you have existing medical conditions or risk factors such as increased age. Also, if you are taking medications for another condition, THC could interact with them.

Cannabis can also affect medications you take

THC can interact with other medications, mainly by increasing or decreasing levels of other medications, including some heart medications. Some examples include:

Warfarin
Cholesterol medications called statins
Blood pressure medications (such as losartan and valsartan)
Antiarrhythmic medications (such as amiodarone)

Can smoking cannabis lead to health problems, even if you’re young?

It’s possible. In theory, there is likely less risk to the heart if you have no underlying heart disease or risk factors. But a large study showed an increased risk in men under age 55 and women under age 65 with cannabis use, regardless of whether they smoked tobacco. Additionally, there are more younger cannabis users being hospitalized for cardiovascular causes.

There are other potential risks to young people, including how cannabis use can impact brain development. Teenagers, pregnant people, or nursing mothers should avoid it for those reasons.

There are additional risks to smoking or vaping that carry similar risks as tobacco smoking. It can cause damage to the lungs and long-term respiratory problems such as chronic bronchitis.

Another concern is the risk of contaminants in marijuana products. The FDA has warned of the risk of lung injury from vitamin E acetate in THC products. Because these products are not regulated or inspected, there is a real risk of contamination with heavy metals, pesticides, or other chemicals.

The bottom line

Cannabis use is increasing in the U.S. and worldwide, especially in older people. There is increased access to cannabis products, and knowledge is growing of its potential medical benefits. Cannabis, and specifically THC, can have real and dangerous risks for your heart health. While more research is needed, it’s important to be aware of these risks for all users, and especially for those who may be at higher risk for heart problems.