Marijuana made my heart pound

Dear Alice,

I recently smoked marijuana, and while I was stoned, my heart pounded rapidly. Is this a normal effect of the drug, an allergic reaction, or something else??

Dear Reader, 

It’s hard to definitively determine what caused your heart to pound, but there are multiple possibilities. It might be that you experienced it as a common side effect of marijuana use. It’s also possible that your experience was due to feeling anxious, which could have been caused or exacerbated by marijuana use. Additionally, the marijuana you used could have been laced with another substance, causing your heart rate to suddenly increase. Although allergic reactions to marijuana have been reported, a rapidly pounding heart hasn't been one of the symptoms associated with this reaction. But regardless of what the cause is, a pounding heart isn’t a reaction to be taken lightly. As such, if you have another similar experience, speaking with your health care provider can help determine the cause and help prevent future recurrences. Interested in “hashing” this out more? Keep on reading! 

Before skipping a beat, it may be helpful to know what happens to your body when you smoke marijuana. When smoked, tetrahydrocannabinol (THC) passes through the lungs and into the bloodstream, which induces feelings of euphoria and relaxation, increases a person’s heart rate and blood pressure, alters their sense and perception of time, or triggers feelings of anxiety, fear, or panic. However, it’s worth mentioning that not all “highs” are experienced the same way, as these side effects may vary from person to person. They may also differ depending on how much marijuana a person has ingested and the type of marijuana being used. It’s also possible that you experienced a side effect that others don’t or may not experience to the same degree. 

While marijuana helps some individuals relax and ease their anxiety, it may induce or exacerbate it in others. For those who are less experienced with its use, the uncertainty surrounding their marijuana experience might cause them to develop symptoms of anxiety and panic attacks, such as a racing heart. For others with generalized anxiety disorder, marijuana may encourage negative thinking which can also worsen their symptoms and lead to a racing heart. As such, if you suspect or know you have anxiety and are likely to experience similar uncomfortable reactions, you may choose to avoid using marijuana in the future. 

While it’s possible that the marijuana itself made your heart pound, it might also be that the marijuana you smoked was laced with another drug. Sometimes, marijuana is cut with hallucinogens (such as phencyclidine, more commonly known as PCP) or other substances that may cause serious adverse effects. Some of these effects can include: 

  • Heart arrhythmia (irregular heart beating) 
  • Difficulty breathing 
  • Significant changes in blood pressure 
  • Heart attack 

Keep in mind that unless you get marijuana from a supervised dispensary, it can be hard to know what you're getting since there are many inconsistencies with drugs that aren't regulated. 

Regardless, a rapidly pounding heart is worth directing your attention towards. If you notice it happening under any other circumstances, especially if it begins to happen more frequently, speaking with your health care provider is strongly advised. Likewise, you may want to think about whether you're interested in continuing to smoke marijuana or not. You may try weighing the pros and cons of doing so now that you know a bit more about what may have contributed to your experiences. What do you like about smoking marijuana? What don’t you like? Could there be other ways to find that same “high” without using substances that could have potentially undesired side effects? Reflecting on some of these questions may help you figure out your next steps and how you’d like to use or not use marijuana moving forward. 

Last updated Apr 30, 2021
Originally published Jan 24, 1997